Acta Psychiatr Scand 2015: 131: 206–212 All rights reserved DOI: 10.1111/acps.12334
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd ACTA PSYCHIATRICA SCANDINAVICA
Prevalence and correlates of cigarette smoking among patients with schizophrenia in southeast Nigeria Aguocha CM, Aguocha JK, Igwe M, Uwakwe RU, Onyeama GM. Prevalence and correlates of cigarette smoking among patients with schizophrenia in southeast Nigeria.
C. M. Aguocha1, J. K. Aguocha2,
M. Igwe3, R. U. Uwakwe4, G. M. Onyeama5 1
Objective: To determine the prevalence of cigarette smoking among patients with schizophrenia and to explore their sociodemographic and clinical characteristics. Method: A cross-sectional descriptive study of 367 patients with schizophrenia. Instruments administered included sociodemographic questionnaire, Present State Examination: schizophrenia section to confirm schizophrenia diagnosis and Present State Examination: tobacco section to those that smoked. Results: A total of 189 females (51.5%) and 178 (48.5%) males were studied. The mean age of the participants was 34.1 9.94 years. Two hundred and forty-one (65.7%) had never being married. Two hundred and three (55.3%) had secondary school education. A lifetime prevalence of 25.9% and a current smoking rate of 20.4% were reported. Ninety five (53.4%) of the males had smoked at least once in their lifetime. None of the females smoked. Among those that smoked, being unmarried (ϰ² = 6.51, P < 0.01) and unemployed (ϰ² = 5.11, P < 0.02) were associated with prescription of high doses of antipsychotics. Of those that smoked, the managing psychiatrist identified or documented only twenty-five (26.3%) of them (kappa = 0.80, P < 0.00). Conclusion: The rate of smoking in Nigerian patients with schizophrenia is considerably less than is reported for their Western counterparts.
Department of Medicine, Imo State University Teaching Hospital, Orlu, Imo State, 2Department of Surgery, Imo State University Teaching Hospital, Orlu, Imo State, 3 Department of Psychological Medicine, Ebonyi State University, Abakaliki, Ebonyi State, 4Faculty of Medicine, Nnamdi Azikiwe University, Awka, Anambra State and 5 Department of Psychological Medicine, University of Nigeria Teaching Hospital, Enugu, Nigeria
Key words: schizophrenia; comorbidity; tobacco Chinyere Aguocha, Department of Medicine, Imo State University Teaching Hospital, Orlu, Imo State, Nigeria. E-mail: [email protected]
Accepted for publication August 18, 2014
Significant outcomes
• There is a lower rate of cigarette smoking among Nigerian patients with schizophrenia compared to their Western counterparts.
• There is low rate of identification of cigarette smoking among patients with schizophrenia in Nigeria. • There is increased rate of smoking among males with schizophrenia compared to their female counterparts in Nigeria.
Limitations
• The causality of relationships between smoking and demographic and clinical variables could not be explored because of the cross-sectional nature of the study.
• It was also a cross-sectional non-population representative study, and the results cannot be generalized to the entire population.
• The estimation of cigarette smoking habits was by self-report. A hundred percent reliability cannot be guaranteed.
206
Cigarette smoking in schizophrenia Introduction
It has been suggested that prolonged daily use of cigarettes is one of the most prevalent, deadly, and yet most preventable of all mental health problems but is often overlooked by the psychiatric profession (1, 2). Smoking-related fatal diseases have been shown to be commoner among people with schizophrenia than among the general population (3). And most of the excess avoidable mortality in patients with schizophrenia has been attributed to cigarette smoking. Smoking lowers the therapeutic effects of many psychoactive agents (4), and its withdrawal leads to a worsening of mood, anxiety, and cognition (5). Smoking has also been seen as a marker for more severe schizophrenia illness process (6) with smokers having an earlier illness onset, greater rate of rehospitalization, and need for higher doses of medication (7, 8). It is also known from studies in Western countries that over 85% of patients with schizophrenia smoke (8, 9) at three times the rate in the general populace (10, 11) and about 52% of these are heavy smokers (12). However, reports from developing countries (China, India) record lower rates of smoking in patients with schizophrenia suggesting that smoking is not invariably high in psychiatric patients (13). A prevalence rate of 33.9% lifetime smoking and 28.5% current smoking rates were reported in Chinese out-patients with schizophrenia (9). The rate of smoking has been studied among selected populations in Nigeria. A wide variation in rates has been recorded. This could be accounted for by methodological differences, differences in age and academic status of the population studied, and the year the study was carried out and region of the country. A very large study carried out in 21 states of the 36 in Nigeria in 2007 reported a 3% prevalence rate for cigarette smoking in the general populace (14). The rates vary across different regions of the country ranging from 8.6% among rural dwellers in southwest Nigeria (15) to 31.9% in northeast Nigeria (16). A descriptive study conducted among 1,183 secondary school students selected by multistage sampling from each of the six geopolitical zones in Nigeria recorded a lifetime smoking prevalence of 26.4% and current smoking prevalence of 17.1% (17). Another study conducted among 1200 female secondary school students in Anambra State, southeast of Nigeria concluded that the prevalence of cigarette smoking in young Nigerian females was relatively low (7.7%) (18). But another study carried out among undergraduate students of the University of Ilorin, Kwara State in the North
Central region of Nigeria reported a much lower prevalence rate of current smoking among females (2.0%) compared with 7.7% among the males of the same institution (19). In a number of cross-sectional studies, current smoking in in-patient and out-patient settings has frequently been associated with younger age, earlier age at onset of schizophrenia and higher doses of neuroleptic medication (8). Other studies have reported that male sex, unemployment, older age, being unmarried, and longer illness duration to be significantly associated with smoking (20, 21). Smokers are known to require higher levels of antipsychotics than non-smokers (22). In patients with schizophrenia who smoke, blood levels of some antipsychotics have been known to be reduced by as much as 50% (23). But a 2-year follow-up study of out-patients with schizophrenia carried out in Turkey reported no significant difference in the dosage of antipsychotics between smokers and non-smokers with schizophrenia at baseline assessment (9, 21). Aims of the study
Cigarette smoking is known to co-occur commonly in schizophrenia. Unfortunately, there is a dearth of literature about this important comorbid disorder in our environment. Therefore, it becomes necessary to study it, so that clinicians will be alert to its presence in their patients. This study aims to determine the prevalence and sociodemographic factors that correlate with cigarette smoking in patients with schizophrenia in a mental health facility in southeastern Nigeria. Material and methods
This is a descriptive cross-sectional study carried out at the out-patient department of Federal Neuropsychiatric Hospital, Enugu between May and December 2011. This is a large urban psychiatric hospital located in the southeastern region of Nigeria. On each clinic day, the medical records of all attending patients with a diagnosis of schizophrenia made by a consultant psychiatrist or a senior trainee psychiatrist (Resident Doctor) according to ICD-10 criteria and who were being managed at the out-patient department of Federal Neuropsychiatric Hospital Enugu were selected. Using a simple random sampling (balloting), four patients were selected to be studied for the day. This number was based on the experience of the burden of the study interview and other logistics that would make it near impossible to interview more than 207
Aguocha et al. four persons a day. There were no refusals by any selected potential participant. In all, total of 367 patients were recruited for the study. By self-report and from the medical records, the participants had no other important physical condition or mental disorder (other substance use disorders) besides schizophrenia. Patients with schizophrenia who get admitted to the in-patient service of the study facility are usually in a very severe psychotic state and would not easily provide any reliable information about their smoking status. We chose to use a fairly homogenous out-patient schizophrenia population. We had our inclusion to be only Present State Examination 10 (PSE-10) confirmed schizophrenia with the capacity (not too ill) to undergo the study interview. The PSE-10 definition of ‘ever smoked’ was adopted as the operational identification of ‘life time smoker,’ whereas ‘current smoking’ refers to ‘having smoked or having been smoking in the past four weeks,’ irrespective of frequency or number of cigarettes. Similarly, the onset age of smoking was taken as the first time in life the interviewee ever smoked a cigarette. For each selected participant, schizophrenia schedule of PSE-10 was administered to confirm the diagnosis followed by sociodemographic questionnaire. Information about the participants such as age, sex, marital status, level of education, religious affiliation, occupation, age of onset of schizophrenia, use of anticholinergic medication, and duration of illness was obtained and coded into a proforma.
For those that answered ‘yes’ to the single item smoking screen ‘Have you ever smoked cigarettes, cigar or pipe in your life?’ PSE-10 smoking schedule was administered. Following the study interviews, the following pieces of information were extracted from the medical records of the participants: current type and dosage of antipsychotic medication, and where applicable information about the participant (sociodemographic data). Antipsychotic medications used by the participants were converted to their chlorpromazine equivalents (24, 25). Data were analyzed using the Personal Computer version of Statistical Package for the Social Sciences (SPSSPC) Version 15. All tests of significance were two-tailed at the 5% level and confidence interval estimation at 95%. Results
There were a total of 367 participants. The mean age of smoking onset reported by the participants was 19.1 3.7 years (range 13–33 years). The mean age of onset of schizophrenia for the participants that smoked was 24.37 5.72 years. The mean number of cigarettes smoked daily during the past 1 year was 3.8 3.5 sticks (range 1–20 sticks per day). Table 1 shows the sociodemographic and clinical characteristics of the whole sample and the comparison between ever smokers and non-smokers with regard to sociodemographic and clinical data. Ninety five (25.9%), representing over half of the male participant population (95 males or
Table 1. Subject characteristics Whole sample
N
Variables Gender Female Male Age (years) 10–29 30–49 50–69 Mean SD Marital status Married Not married Educational level No formal education Formal education Employment status Employed Unemployed
208
Ever smoked
Percent (%)
189 178
51.5 48.5
134 196 37 34.1 9.9
N Yes (%)
Percent (%) No (%)
Stat
95 (53.4)
189 (100) 83 (46.6)
36.5 53.4 10.1
40 (40.0) 49 (51.6) 8 (8.5) 33.51 9.42
96 (35.3) 147 (54.1) 29 (10.7) 34.31 10.13
t = 0.67 P < 0.50
87 280
23.7 76.3
26 (27.4) 69 (72.6)
61 (22.4) 211 (77.6)
ϰ² = 0.81 P < 0.37
16 351
4.4 95.6
1 (1.1) 94 (98.9)
15 (5.5) 257 (94.5)
ϰ² = 0.01 P < 0.91
164 203
44.7 55.3
42 (44.2) 53 (55.8)
122 (44.9) 150 (55.1)
ϰ² = 0.01 P < 0.91
Cigarette smoking in schizophrenia 53.4%), of all the participants had smoked at least once in their lifetime, while no females ever smoked. There was no statistically significant difference between smokers and non-smokers in terms of age, marital status, educational, and employment status. Table 2 shows the comparison between the sociodemographic distribution of the participants that currently smoked and those that did not. Seventy five (20.4%) of all the participants (all males) currently smoked and mostly fell into the age group 30–49 years. Of those that currently smoked, 22 (29.3%) were dependent on tobacco. Of these, 19 (86.4%) were single, while 3 (13.6%) were married (ϰ = 1.46, P < 0.48). Most of them, 14 (63.6%) were aged between 30 and 49 years. Twelve (54.5%) were unemployed, while 17 (77.3%) had been ill for more than 3 years. The mean dosage of antipsychotics (in chlorpromazine equivalent) used among all the participants per day was 417.8 297.0 mg (range 50–1325 mg). The median dosage was 325 mg. The participants were dichotomized into ‘low dose’ (i.e. below median dose) and ‘high dose’ (i.e. median dose and above). Among the participants that currently smoked, the mean dosage of antipsychotics per day (in chlorpromazine equivalent) was 427.7 250.0 mg compared with 415.3 308.2 mg for those that did not currently smoke (t = 0.32, P < 0.7). The mean daily dosage of anticholinergic medication (Artane) was 4.9 2.8 mg for those that smoked and Table 2. Comparison of sociodemographic distribution of current smokers and noncurrent smokers Currently smoke
Variables Sex Male Female Age (years) 10–29 30–49 50–69 Mean SD Marital status Married Not married Educational level No formal education Formal education Employment status Employed Not employed
Yes N (%)
No N (%)
75 (42.1) –
103 (57.9) 189 (100)
44 (45.3) 35 (46.6) 6 (8.0) 32.63 9.27
80 (34.3) 161 (55.1) 31(10.6) 34.48 10.09
17 (22.7) 58 (77.3)
Test statistic
t=
P-value
1.44
P < 0.15
70 (24.0) 222 (76.0)
ϰ² = 0.06
P < 0.81
1 (1.3)
15 (5.1)
ϰ² = 2.07
P < 0.15
74 (98.7)
277 (94.9)
31 (41.3) 44 (58.7)
133 (45.5) 159 (54.5)
4.6 2.4 mg for those that did not (t = 0.83, P < 0.41). Table 3 shows the distribution of antipsychotic dosage among the participants that smoked. Most of the participants that smoked were on antipsychotic medications above the median dose. In Table 4, it is seen that there is a significant association between marital status and dosage of antipsychotic prescribed among those that had ever smoked. Those who were married were more likely to be on lower dosage of antipsychotic (ϰ² = 6.51, P < 0.01). Those that were unemployed were more likely to be on higher dosage of antipsychotics compared with those that were employed (ϰ² = 5.11, P < 0.02). Table 5 shows the association between current smoking and the type of antipsychotic prescribed. There was no significant association between the type of antipsychotic prescribed and current smoking habit (ϰ² = 0.55, P < 0.48). Ninety-five participants had smoked at least once in their lifetime of whom the managing psychiatrists identified or documented only 25 (26.3%) (kappa = 0.80, P < 0.01). Discussion
The study reaffirmed the findings in other studies that cigarette smoking is mainly a male affair, and this is especially true in the Nigerian environment (14). This is in agreement with previous studies that reported a preponderance of smoking in males with schizophrenia (9, 26). It would be expected that the rate of smoking by patients who have schizophrenia would mirror the smoking profile of the base population. As presented in the literature review, it would appear that the rate of smoking in Africa and Nigeria in particular is quite low compared with other countries. Yet it has been argued that while smoking consumption seems to be decreasing in developed countries, the rate is rising in developing countries (27). What is evident in the present study is that smoking rate in Nigerian patients with schizophrenia is lower than the reports from developing
Table 3. Distribution of antipsychotic dosage among those that smoked Variable
Dosage ϰ² = 0.43
P < 0.51
High dose Low dose
Ever smoked
Currently smoke
Yes n (%)
No n (%)
Yes n (%)
No n (%)
53 (55.8) 42 (44.2)
136 (50) 136 (50)
43 (57.3) 32 (42.7)
146 (50) 146 (50)
209
Aguocha et al. Table 4. Association between dosage of antipsychotics and sociodemographic variables of participants that have ever smoked Dosage of antipsychotic
Variable Gender Male Marital status Married Not married Educational level Formal education No formal education Employment status Employed Not employed
High dose N (%)
Low dose N (%)
53 (55.8)
42 (44.2)
9 (34.6) 44 (63.8)
17 (65.4) 25 (36.2)
53 (56.4) _
41 (43.6) 1 (100)
18 (42.9) 35 (66)
24 (57.1) 18 (34)
Test statistic
P-value
ϰ² = 6.51
P < 0.01
ϰ² = 5.11
P < 0.02
countries, but is much higher than in the general Nigerian population. Nigerian female patients with schizophrenia as indeed their well counterparts are less likely to be smokers. Generally in Africa, a continent copiously defined by cherished cultural values and norms, society frowns at females who smoke and negatively stereotypes such females. It is understandable that in a population of African people with schizophrenia, the smoking rate would be low or non-existent in females. In practical terms, smoking cessation programmes in Africa must be aggressively targeted against males, especially those with psychotic disorders including schizophrenia. The mean age of smoking inception was earlier than the mean age of onset of schizophrenia. This is similar to findings in previous reports that smoking started before the onset of schizophrenia (28– 30). This implies that smoking started before the prescription of antipsychotic medications. Although the causal implications of smoking antedating the onset of schizophrenia is not known, it is possible that smoking could be related to the pathophysiological features of schizophrenia. It has not been clearly proved that patients with psychotic symptoms use smoking as an attempt to alleviate either their abnormal experiences or the side-effects of medication (31). It is unclear if Table 5. Association between type of antipsychotic prescribed and smoking status Current smoking
Type of antipsychotic
Yes N (%)
No N (%)
Typical Antipsychotic Atypical Antipsychotic
66 (88) 9 (12)
247 (84.6) 45 (15.4)
210
Test statistic
P-value
ϰ² = 0.55
P < 0.48
smoking predisposes to schizophrenia or renders smokers vulnerable to developing schizophrenia (32, 33). The mean dosage of antipsychotic prescribed for participants who currently smoked was 427.7 250.0 mg. This was close to 565.5 205.8 mg prescribed to out-patients with schizophrenia who smoked in a study carried out in Turkey (21) and 548 mg in Chinese patients (9). The difference may be due to hospital antipsychotic management protocol (some hospitals prescribe heavier antipsychotic medication than others). There was a 12 mg difference in the dosage of antipsychotics prescribed to those that smoked and those that did not, with smokers receiving a higher dose. This was similar to 10 mg difference reported in a similar study in China (9). However, there was no statistically significant difference in the dosage of antipsychotic prescribed for those who smoked and those who did not. This is similar to what was found in a follow-up study carried out in Turkey which reported no significant difference in the dosage of antipsychotics between smokers and non-smokers with schizophrenia at baseline assessment (21). Among the participants studied, there was no significant relationship between the type of antipsychotic prescribed (i.e., as to whether typical or atypical) and current smoking status. This is in contrast to a previous work that reported that current smokers were significantly likely to be on first generation antipsychotic medication (34). This may be due to differences in prescription pattern caused by the inability of many families in southeast Nigeria to afford atypical antipsychotics because payment is out of pocket. In the study cited above, there was almost an equal percentage of prescription of typical and atypical antipsychotics. This study reported a low rate of identification of smoking in routine clinical practice. This was similar to a low rate of identification by psychiatrists in a sample of psychiatric patients seen in routine clinical practice (2). This low identification rate may be due to poor assessment or more attention being paid to illicit drugs. This disposition would be expected to result in non-management of smoking problems in patients with schizophrenia. Without adequate recognition and treatment, the economic and adverse health consequences of smoking in this group of patients will add a heavy burden to the society. Clinicians in Africa should have a low threshold of identification of smoking problems in patients with mental disorders such as schizophrenia and not be misled to think that the
Cigarette smoking in schizophrenia low rate of smoking in the general population applies to a sick population. This study also found that among those participants that smoked, those who were unmarried and unemployed were significantly more likely to get a prescription of higher dosage of antipsychotic. Employment and marital status are considered important measures of disability in schizophrenia (35–37). Marriage offers caregiving and social support to patients with mental illness and may also offer emotional stability. It is also a major source of psychological adjustment (38). These may reduce the severity of illness in these patients leading to reduced need for antipsychotics. On the other hand, being unemployed is a major social stressor to patients with schizophrenia. Thus, being unmarried and unemployed may affect outcome negatively with more symptoms and poorer functioning leading to high medication (39). The study has shown that smoking in schizophrenia is poorly detected in our environment. Given the harmful consequence of smoking and its preventable nature, effective measures to improve its detection and promotion of smoking cessat ion in schizophrenia should be implemented in Nigerian patients. References 1. Di Franza J, Rigotti N, McNeill A et al. Initial symptoms of Nicotine dependence in adolescents. Tob Control 2000;9:313–319. 2. Montoya I, Herbeck D, Svikis D, Pincus H. Identification and treatment of patients with nicotine problems in routine clinical psychiatry practice. Am J Addiction 2005;14:441–445. 3. McNeill A. Smoking and mental health – a review of the literature: symposium report: smoking and mental health. London: Royal Pharmaceutical Society, 2001. 4. Miller R. Effect of smoking on drug action. Clin Pharmacol Ther 1979;22:749–756. 5. Gilbert D. Paradoxical tranquilizing and emotion reducing effects of nicotine. Psychol Bull 1979;86:643–662. 6. De Leon J. Smoking and vulnerability for schizophrenia. Schizophr Bull 1996;22:405–409. 7. Ziedonis D, Kosten T, Glazer W, Frances R. Nicotine dependence and schizophrenia. Hosp Community Psychiatry 1994;45:204–206. 8. Goff D, Henderson D, Amico E. Cigarette smoking in schizophrenia: relationship to psychopathology and medication side-effects. Am J Psychiatry 1992;149:1189–1194. 9. Chong S, Choo H. Smoking among Chinese patients with schizophrenia. Aust NZ J Psychiatry 1996;30:350–353. 10. Hughes J, Hatsukami D, Mitchell J, Dahlgren L. Prevalence of smoking among psychiatric outpatients. Am J Psychiatry 1986;143:993–997. 11. George T, Vessicchio J. Nicotine addiction and schizophrenia. Psychiatric Times 2001;18:39–42. 12. Lasser K, Boyd J, Woolhandler S, Himmelstein D, McCormick D, Bor D. Smoking and mental illness. A populationbased prevalence study. JAMA 2000;284:2606–2610.
13. Srinivasan T, Thara R. Smoking in schizophrenia – all is not biological. Schizophr Res 2002;1:67–74. 14. Gureje O, Degenhardt L, Olley B et al. A descriptive epidemiology of substance use and substance use disorders in Nigeria during the early 21st century. Drug Alcohol Depend 2007;91:1–9. 15. Ayankogbe O, Inem O, Bamgbala O, Robert O. Attitudes and determinant of cigarette smoking among rural dwellers South West Nigeria. Niger Med Pract 2003;44:70–74. 16. Desalu O, Olokoba A, Danburam A, Salawu F, Issa B. Epidemiology of tobacco smoking among adults population in North-East Nigeria. Int J Epidemiol 2007;6:1. 17. Odeyemi K, Osibogun A, Akinsete A, Sadiq L. The prevalence and predictors of cigarette smoking among secondary school students in Nigeria. Niger Postgrad Med J 2009;16:40–45. 18. Ibe CC, Ele PU. Prevalence of cigarette smoking in young Nigerian females. Afr J of Med Med Sc 2003;32:335–338. 19. Fawibe A, Shittu A. Prevalence and characteristics of cigarette smokers among undergraduates of the University of Ilorin, Nigeria. Nige J Clin Pract 2011;2:201–205. 20. Wang C, Xiang Y, Weng Y et al. Cigarette smoking in patients with Schizophrenia in China: prospective Multicentre Study. Aust NZ J Psychiatry 2010;44:456–462. € ßahin A. Smoking and 21. Uzun O, Cansever A, Basoglu C, Ozs substance abuse in outpatients with schizophrenia: a 2year follow-up study in Turkey. Drug Alcohol Depen 2003;70:187–192. 22. Salokanga R, Saarijarvi S, Taiminen T et al. Effect of smoking on neuroleptics in schizophrenia. Schizophr Res 1997;23:55–60. 23. Ziedonis D, George T. Schizophrenia and nicotine use: report of a pilot smoking cessation program and review of neurobiological and clinical issues. Schizophr Bull 1997;23:247–254. 24. American Psychiatric Association. Practice guideline for the treatment of patients with schizophrenia. Am J Psychiatry 1997;154:1–63. 25. Woods S. Chlorpromazine equivalent doses for the newer atypical antipsychotics. J Clin Psychiatry 2003;64:663– 667. 26. Eisen J, Beer D, Pato M, Venditto T, Rasmussen S. Obsessive-compulsive disorder in patients with schizophrenia or schizoaffective disorder. Am J Psychiatry 1997;154:271– 273. 27. The World Bank Group, Economics of Tobacco Control, Section III. Demand for tobacco. Tobacco advertising and promotion. OUP: World Bank, 2000. 28. Ma X, Li C, Meng H et al. Premorbid tobacco smoking is associated with later age at onset in schizophrenia. Psychiatry Res 2010;178:461–466. 29. Kelly C, McCreadie R. Smoking habits, current symptoms, and premorbid characteristics of schizophrenic patients in Nithsdale, Scotland. Am J Psychiatry 1999;156:1751–1757. 30. Beratis S, Katrivanou A, Gourzis P. Factors affecting smoking in schizophrenia. Compr Psychiat 2001;45:393– 402. 31. McEvoy J, Brown S. Smoking in first-episode patients with schizophrenia. Am J Psychiatry 1999;156:1120–1121. 32. Dalack G, Meador-Woodruff J. Smoking, smoking withdrawal and schizophrenia: case reports and review of literature. Schizophr Res 1996;22:133–141. 33. Winterer G. Why do patients with Schizophrenia smoke? Curr Opin Psychiatry 2010;23:112–119.
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© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd ACTA PSYCHIATRICA SCANDINAVICA
Prevalence and correlates of cigarette smoking among patients with schizophrenia in southeast Nigeria Aguocha CM, Aguocha JK, Igwe M, Uwakwe RU, Onyeama GM. Prevalence and correlates of cigarette smoking among patients with schizophrenia in southeast Nigeria.
C. M. Aguocha1, J. K. Aguocha2,
M. Igwe3, R. U. Uwakwe4, G. M. Onyeama5 1
Objective: To determine the prevalence of cigarette smoking among patients with schizophrenia and to explore their sociodemographic and clinical characteristics. Method: A cross-sectional descriptive study of 367 patients with schizophrenia. Instruments administered included sociodemographic questionnaire, Present State Examination: schizophrenia section to confirm schizophrenia diagnosis and Present State Examination: tobacco section to those that smoked. Results: A total of 189 females (51.5%) and 178 (48.5%) males were studied. The mean age of the participants was 34.1 9.94 years. Two hundred and forty-one (65.7%) had never being married. Two hundred and three (55.3%) had secondary school education. A lifetime prevalence of 25.9% and a current smoking rate of 20.4% were reported. Ninety five (53.4%) of the males had smoked at least once in their lifetime. None of the females smoked. Among those that smoked, being unmarried (ϰ² = 6.51, P < 0.01) and unemployed (ϰ² = 5.11, P < 0.02) were associated with prescription of high doses of antipsychotics. Of those that smoked, the managing psychiatrist identified or documented only twenty-five (26.3%) of them (kappa = 0.80, P < 0.00). Conclusion: The rate of smoking in Nigerian patients with schizophrenia is considerably less than is reported for their Western counterparts.
Department of Medicine, Imo State University Teaching Hospital, Orlu, Imo State, 2Department of Surgery, Imo State University Teaching Hospital, Orlu, Imo State, 3 Department of Psychological Medicine, Ebonyi State University, Abakaliki, Ebonyi State, 4Faculty of Medicine, Nnamdi Azikiwe University, Awka, Anambra State and 5 Department of Psychological Medicine, University of Nigeria Teaching Hospital, Enugu, Nigeria
Key words: schizophrenia; comorbidity; tobacco Chinyere Aguocha, Department of Medicine, Imo State University Teaching Hospital, Orlu, Imo State, Nigeria. E-mail: [email protected]
Accepted for publication August 18, 2014
Significant outcomes
• There is a lower rate of cigarette smoking among Nigerian patients with schizophrenia compared to their Western counterparts.
• There is low rate of identification of cigarette smoking among patients with schizophrenia in Nigeria. • There is increased rate of smoking among males with schizophrenia compared to their female counterparts in Nigeria.
Limitations
• The causality of relationships between smoking and demographic and clinical variables could not be explored because of the cross-sectional nature of the study.
• It was also a cross-sectional non-population representative study, and the results cannot be generalized to the entire population.
• The estimation of cigarette smoking habits was by self-report. A hundred percent reliability cannot be guaranteed.
206
Cigarette smoking in schizophrenia Introduction
It has been suggested that prolonged daily use of cigarettes is one of the most prevalent, deadly, and yet most preventable of all mental health problems but is often overlooked by the psychiatric profession (1, 2). Smoking-related fatal diseases have been shown to be commoner among people with schizophrenia than among the general population (3). And most of the excess avoidable mortality in patients with schizophrenia has been attributed to cigarette smoking. Smoking lowers the therapeutic effects of many psychoactive agents (4), and its withdrawal leads to a worsening of mood, anxiety, and cognition (5). Smoking has also been seen as a marker for more severe schizophrenia illness process (6) with smokers having an earlier illness onset, greater rate of rehospitalization, and need for higher doses of medication (7, 8). It is also known from studies in Western countries that over 85% of patients with schizophrenia smoke (8, 9) at three times the rate in the general populace (10, 11) and about 52% of these are heavy smokers (12). However, reports from developing countries (China, India) record lower rates of smoking in patients with schizophrenia suggesting that smoking is not invariably high in psychiatric patients (13). A prevalence rate of 33.9% lifetime smoking and 28.5% current smoking rates were reported in Chinese out-patients with schizophrenia (9). The rate of smoking has been studied among selected populations in Nigeria. A wide variation in rates has been recorded. This could be accounted for by methodological differences, differences in age and academic status of the population studied, and the year the study was carried out and region of the country. A very large study carried out in 21 states of the 36 in Nigeria in 2007 reported a 3% prevalence rate for cigarette smoking in the general populace (14). The rates vary across different regions of the country ranging from 8.6% among rural dwellers in southwest Nigeria (15) to 31.9% in northeast Nigeria (16). A descriptive study conducted among 1,183 secondary school students selected by multistage sampling from each of the six geopolitical zones in Nigeria recorded a lifetime smoking prevalence of 26.4% and current smoking prevalence of 17.1% (17). Another study conducted among 1200 female secondary school students in Anambra State, southeast of Nigeria concluded that the prevalence of cigarette smoking in young Nigerian females was relatively low (7.7%) (18). But another study carried out among undergraduate students of the University of Ilorin, Kwara State in the North
Central region of Nigeria reported a much lower prevalence rate of current smoking among females (2.0%) compared with 7.7% among the males of the same institution (19). In a number of cross-sectional studies, current smoking in in-patient and out-patient settings has frequently been associated with younger age, earlier age at onset of schizophrenia and higher doses of neuroleptic medication (8). Other studies have reported that male sex, unemployment, older age, being unmarried, and longer illness duration to be significantly associated with smoking (20, 21). Smokers are known to require higher levels of antipsychotics than non-smokers (22). In patients with schizophrenia who smoke, blood levels of some antipsychotics have been known to be reduced by as much as 50% (23). But a 2-year follow-up study of out-patients with schizophrenia carried out in Turkey reported no significant difference in the dosage of antipsychotics between smokers and non-smokers with schizophrenia at baseline assessment (9, 21). Aims of the study
Cigarette smoking is known to co-occur commonly in schizophrenia. Unfortunately, there is a dearth of literature about this important comorbid disorder in our environment. Therefore, it becomes necessary to study it, so that clinicians will be alert to its presence in their patients. This study aims to determine the prevalence and sociodemographic factors that correlate with cigarette smoking in patients with schizophrenia in a mental health facility in southeastern Nigeria. Material and methods
This is a descriptive cross-sectional study carried out at the out-patient department of Federal Neuropsychiatric Hospital, Enugu between May and December 2011. This is a large urban psychiatric hospital located in the southeastern region of Nigeria. On each clinic day, the medical records of all attending patients with a diagnosis of schizophrenia made by a consultant psychiatrist or a senior trainee psychiatrist (Resident Doctor) according to ICD-10 criteria and who were being managed at the out-patient department of Federal Neuropsychiatric Hospital Enugu were selected. Using a simple random sampling (balloting), four patients were selected to be studied for the day. This number was based on the experience of the burden of the study interview and other logistics that would make it near impossible to interview more than 207
Aguocha et al. four persons a day. There were no refusals by any selected potential participant. In all, total of 367 patients were recruited for the study. By self-report and from the medical records, the participants had no other important physical condition or mental disorder (other substance use disorders) besides schizophrenia. Patients with schizophrenia who get admitted to the in-patient service of the study facility are usually in a very severe psychotic state and would not easily provide any reliable information about their smoking status. We chose to use a fairly homogenous out-patient schizophrenia population. We had our inclusion to be only Present State Examination 10 (PSE-10) confirmed schizophrenia with the capacity (not too ill) to undergo the study interview. The PSE-10 definition of ‘ever smoked’ was adopted as the operational identification of ‘life time smoker,’ whereas ‘current smoking’ refers to ‘having smoked or having been smoking in the past four weeks,’ irrespective of frequency or number of cigarettes. Similarly, the onset age of smoking was taken as the first time in life the interviewee ever smoked a cigarette. For each selected participant, schizophrenia schedule of PSE-10 was administered to confirm the diagnosis followed by sociodemographic questionnaire. Information about the participants such as age, sex, marital status, level of education, religious affiliation, occupation, age of onset of schizophrenia, use of anticholinergic medication, and duration of illness was obtained and coded into a proforma.
For those that answered ‘yes’ to the single item smoking screen ‘Have you ever smoked cigarettes, cigar or pipe in your life?’ PSE-10 smoking schedule was administered. Following the study interviews, the following pieces of information were extracted from the medical records of the participants: current type and dosage of antipsychotic medication, and where applicable information about the participant (sociodemographic data). Antipsychotic medications used by the participants were converted to their chlorpromazine equivalents (24, 25). Data were analyzed using the Personal Computer version of Statistical Package for the Social Sciences (SPSSPC) Version 15. All tests of significance were two-tailed at the 5% level and confidence interval estimation at 95%. Results
There were a total of 367 participants. The mean age of smoking onset reported by the participants was 19.1 3.7 years (range 13–33 years). The mean age of onset of schizophrenia for the participants that smoked was 24.37 5.72 years. The mean number of cigarettes smoked daily during the past 1 year was 3.8 3.5 sticks (range 1–20 sticks per day). Table 1 shows the sociodemographic and clinical characteristics of the whole sample and the comparison between ever smokers and non-smokers with regard to sociodemographic and clinical data. Ninety five (25.9%), representing over half of the male participant population (95 males or
Table 1. Subject characteristics Whole sample
N
Variables Gender Female Male Age (years) 10–29 30–49 50–69 Mean SD Marital status Married Not married Educational level No formal education Formal education Employment status Employed Unemployed
208
Ever smoked
Percent (%)
189 178
51.5 48.5
134 196 37 34.1 9.9
N Yes (%)
Percent (%) No (%)
Stat
95 (53.4)
189 (100) 83 (46.6)
36.5 53.4 10.1
40 (40.0) 49 (51.6) 8 (8.5) 33.51 9.42
96 (35.3) 147 (54.1) 29 (10.7) 34.31 10.13
t = 0.67 P < 0.50
87 280
23.7 76.3
26 (27.4) 69 (72.6)
61 (22.4) 211 (77.6)
ϰ² = 0.81 P < 0.37
16 351
4.4 95.6
1 (1.1) 94 (98.9)
15 (5.5) 257 (94.5)
ϰ² = 0.01 P < 0.91
164 203
44.7 55.3
42 (44.2) 53 (55.8)
122 (44.9) 150 (55.1)
ϰ² = 0.01 P < 0.91
Cigarette smoking in schizophrenia 53.4%), of all the participants had smoked at least once in their lifetime, while no females ever smoked. There was no statistically significant difference between smokers and non-smokers in terms of age, marital status, educational, and employment status. Table 2 shows the comparison between the sociodemographic distribution of the participants that currently smoked and those that did not. Seventy five (20.4%) of all the participants (all males) currently smoked and mostly fell into the age group 30–49 years. Of those that currently smoked, 22 (29.3%) were dependent on tobacco. Of these, 19 (86.4%) were single, while 3 (13.6%) were married (ϰ = 1.46, P < 0.48). Most of them, 14 (63.6%) were aged between 30 and 49 years. Twelve (54.5%) were unemployed, while 17 (77.3%) had been ill for more than 3 years. The mean dosage of antipsychotics (in chlorpromazine equivalent) used among all the participants per day was 417.8 297.0 mg (range 50–1325 mg). The median dosage was 325 mg. The participants were dichotomized into ‘low dose’ (i.e. below median dose) and ‘high dose’ (i.e. median dose and above). Among the participants that currently smoked, the mean dosage of antipsychotics per day (in chlorpromazine equivalent) was 427.7 250.0 mg compared with 415.3 308.2 mg for those that did not currently smoke (t = 0.32, P < 0.7). The mean daily dosage of anticholinergic medication (Artane) was 4.9 2.8 mg for those that smoked and Table 2. Comparison of sociodemographic distribution of current smokers and noncurrent smokers Currently smoke
Variables Sex Male Female Age (years) 10–29 30–49 50–69 Mean SD Marital status Married Not married Educational level No formal education Formal education Employment status Employed Not employed
Yes N (%)
No N (%)
75 (42.1) –
103 (57.9) 189 (100)
44 (45.3) 35 (46.6) 6 (8.0) 32.63 9.27
80 (34.3) 161 (55.1) 31(10.6) 34.48 10.09
17 (22.7) 58 (77.3)
Test statistic
t=
P-value
1.44
P < 0.15
70 (24.0) 222 (76.0)
ϰ² = 0.06
P < 0.81
1 (1.3)
15 (5.1)
ϰ² = 2.07
P < 0.15
74 (98.7)
277 (94.9)
31 (41.3) 44 (58.7)
133 (45.5) 159 (54.5)
4.6 2.4 mg for those that did not (t = 0.83, P < 0.41). Table 3 shows the distribution of antipsychotic dosage among the participants that smoked. Most of the participants that smoked were on antipsychotic medications above the median dose. In Table 4, it is seen that there is a significant association between marital status and dosage of antipsychotic prescribed among those that had ever smoked. Those who were married were more likely to be on lower dosage of antipsychotic (ϰ² = 6.51, P < 0.01). Those that were unemployed were more likely to be on higher dosage of antipsychotics compared with those that were employed (ϰ² = 5.11, P < 0.02). Table 5 shows the association between current smoking and the type of antipsychotic prescribed. There was no significant association between the type of antipsychotic prescribed and current smoking habit (ϰ² = 0.55, P < 0.48). Ninety-five participants had smoked at least once in their lifetime of whom the managing psychiatrists identified or documented only 25 (26.3%) (kappa = 0.80, P < 0.01). Discussion
The study reaffirmed the findings in other studies that cigarette smoking is mainly a male affair, and this is especially true in the Nigerian environment (14). This is in agreement with previous studies that reported a preponderance of smoking in males with schizophrenia (9, 26). It would be expected that the rate of smoking by patients who have schizophrenia would mirror the smoking profile of the base population. As presented in the literature review, it would appear that the rate of smoking in Africa and Nigeria in particular is quite low compared with other countries. Yet it has been argued that while smoking consumption seems to be decreasing in developed countries, the rate is rising in developing countries (27). What is evident in the present study is that smoking rate in Nigerian patients with schizophrenia is lower than the reports from developing
Table 3. Distribution of antipsychotic dosage among those that smoked Variable
Dosage ϰ² = 0.43
P < 0.51
High dose Low dose
Ever smoked
Currently smoke
Yes n (%)
No n (%)
Yes n (%)
No n (%)
53 (55.8) 42 (44.2)
136 (50) 136 (50)
43 (57.3) 32 (42.7)
146 (50) 146 (50)
209
Aguocha et al. Table 4. Association between dosage of antipsychotics and sociodemographic variables of participants that have ever smoked Dosage of antipsychotic
Variable Gender Male Marital status Married Not married Educational level Formal education No formal education Employment status Employed Not employed
High dose N (%)
Low dose N (%)
53 (55.8)
42 (44.2)
9 (34.6) 44 (63.8)
17 (65.4) 25 (36.2)
53 (56.4) _
41 (43.6) 1 (100)
18 (42.9) 35 (66)
24 (57.1) 18 (34)
Test statistic
P-value
ϰ² = 6.51
P < 0.01
ϰ² = 5.11
P < 0.02
countries, but is much higher than in the general Nigerian population. Nigerian female patients with schizophrenia as indeed their well counterparts are less likely to be smokers. Generally in Africa, a continent copiously defined by cherished cultural values and norms, society frowns at females who smoke and negatively stereotypes such females. It is understandable that in a population of African people with schizophrenia, the smoking rate would be low or non-existent in females. In practical terms, smoking cessation programmes in Africa must be aggressively targeted against males, especially those with psychotic disorders including schizophrenia. The mean age of smoking inception was earlier than the mean age of onset of schizophrenia. This is similar to findings in previous reports that smoking started before the onset of schizophrenia (28– 30). This implies that smoking started before the prescription of antipsychotic medications. Although the causal implications of smoking antedating the onset of schizophrenia is not known, it is possible that smoking could be related to the pathophysiological features of schizophrenia. It has not been clearly proved that patients with psychotic symptoms use smoking as an attempt to alleviate either their abnormal experiences or the side-effects of medication (31). It is unclear if Table 5. Association between type of antipsychotic prescribed and smoking status Current smoking
Type of antipsychotic
Yes N (%)
No N (%)
Typical Antipsychotic Atypical Antipsychotic
66 (88) 9 (12)
247 (84.6) 45 (15.4)
210
Test statistic
P-value
ϰ² = 0.55
P < 0.48
smoking predisposes to schizophrenia or renders smokers vulnerable to developing schizophrenia (32, 33). The mean dosage of antipsychotic prescribed for participants who currently smoked was 427.7 250.0 mg. This was close to 565.5 205.8 mg prescribed to out-patients with schizophrenia who smoked in a study carried out in Turkey (21) and 548 mg in Chinese patients (9). The difference may be due to hospital antipsychotic management protocol (some hospitals prescribe heavier antipsychotic medication than others). There was a 12 mg difference in the dosage of antipsychotics prescribed to those that smoked and those that did not, with smokers receiving a higher dose. This was similar to 10 mg difference reported in a similar study in China (9). However, there was no statistically significant difference in the dosage of antipsychotic prescribed for those who smoked and those who did not. This is similar to what was found in a follow-up study carried out in Turkey which reported no significant difference in the dosage of antipsychotics between smokers and non-smokers with schizophrenia at baseline assessment (21). Among the participants studied, there was no significant relationship between the type of antipsychotic prescribed (i.e., as to whether typical or atypical) and current smoking status. This is in contrast to a previous work that reported that current smokers were significantly likely to be on first generation antipsychotic medication (34). This may be due to differences in prescription pattern caused by the inability of many families in southeast Nigeria to afford atypical antipsychotics because payment is out of pocket. In the study cited above, there was almost an equal percentage of prescription of typical and atypical antipsychotics. This study reported a low rate of identification of smoking in routine clinical practice. This was similar to a low rate of identification by psychiatrists in a sample of psychiatric patients seen in routine clinical practice (2). This low identification rate may be due to poor assessment or more attention being paid to illicit drugs. This disposition would be expected to result in non-management of smoking problems in patients with schizophrenia. Without adequate recognition and treatment, the economic and adverse health consequences of smoking in this group of patients will add a heavy burden to the society. Clinicians in Africa should have a low threshold of identification of smoking problems in patients with mental disorders such as schizophrenia and not be misled to think that the
Cigarette smoking in schizophrenia low rate of smoking in the general population applies to a sick population. This study also found that among those participants that smoked, those who were unmarried and unemployed were significantly more likely to get a prescription of higher dosage of antipsychotic. Employment and marital status are considered important measures of disability in schizophrenia (35–37). Marriage offers caregiving and social support to patients with mental illness and may also offer emotional stability. It is also a major source of psychological adjustment (38). These may reduce the severity of illness in these patients leading to reduced need for antipsychotics. On the other hand, being unemployed is a major social stressor to patients with schizophrenia. Thus, being unmarried and unemployed may affect outcome negatively with more symptoms and poorer functioning leading to high medication (39). The study has shown that smoking in schizophrenia is poorly detected in our environment. Given the harmful consequence of smoking and its preventable nature, effective measures to improve its detection and promotion of smoking cessat ion in schizophrenia should be implemented in Nigerian patients. References 1. Di Franza J, Rigotti N, McNeill A et al. Initial symptoms of Nicotine dependence in adolescents. Tob Control 2000;9:313–319. 2. Montoya I, Herbeck D, Svikis D, Pincus H. Identification and treatment of patients with nicotine problems in routine clinical psychiatry practice. Am J Addiction 2005;14:441–445. 3. McNeill A. Smoking and mental health – a review of the literature: symposium report: smoking and mental health. London: Royal Pharmaceutical Society, 2001. 4. Miller R. Effect of smoking on drug action. Clin Pharmacol Ther 1979;22:749–756. 5. Gilbert D. Paradoxical tranquilizing and emotion reducing effects of nicotine. Psychol Bull 1979;86:643–662. 6. De Leon J. Smoking and vulnerability for schizophrenia. Schizophr Bull 1996;22:405–409. 7. Ziedonis D, Kosten T, Glazer W, Frances R. Nicotine dependence and schizophrenia. Hosp Community Psychiatry 1994;45:204–206. 8. Goff D, Henderson D, Amico E. Cigarette smoking in schizophrenia: relationship to psychopathology and medication side-effects. Am J Psychiatry 1992;149:1189–1194. 9. Chong S, Choo H. Smoking among Chinese patients with schizophrenia. Aust NZ J Psychiatry 1996;30:350–353. 10. Hughes J, Hatsukami D, Mitchell J, Dahlgren L. Prevalence of smoking among psychiatric outpatients. Am J Psychiatry 1986;143:993–997. 11. George T, Vessicchio J. Nicotine addiction and schizophrenia. Psychiatric Times 2001;18:39–42. 12. Lasser K, Boyd J, Woolhandler S, Himmelstein D, McCormick D, Bor D. Smoking and mental illness. A populationbased prevalence study. JAMA 2000;284:2606–2610.
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