Journal
of Psychmomatic
Research,
IS ASTHMA A COMPARATIVE
Vol.
21, pp.
471 to 481.
Pergamon
Press.
A PSYCHOSOMATIC STUDY OF RESPIRATORY MENTAL HEALTH*
1977.
Printed
in Great
Britain
ILLNESS?-II. IMPAIRMENT
AND
SIDNEY BENJAMINt (Received
14 June 1977)
Abstract-The respiratory state and mental health of a group of 47 asthmatics and 43 matched non-asthmatic controls have been compared using standardised interview and respiratory function assessments. Despite physical impairment the asthma group failed to show any significant excess in point prevalence, or any difference in the diagnostic categories of mental illness suffered. There was a tendency for more positive ratings for psychopathology to be made for the asthma group but this was not related to greater physiological impairment. It is suggested that this trend arises mainly due to overreporting of symptoms of all kinds by some members of the asthma group. These results are considered in the light of similar findings in others with respiratory disorder. The importance of bias arising from selection of subjects in research into somatic and psychic relationships is emphasised and the implications for clinical management are discussed.
THE NATURE of the association between asthma and mental illness the management of asthma and for the concept of psychosomatic reports matics
suggested that neurotic and that schizophrenia
is of interest both for illness. Many earlier
disorders are more common than is less common and may alternate
expected in asthwith asthma, but
recent studies fail to support these views. An excess of neurotic illness in asthmatics appears to be limited to disorders in children [l]; is related to the severity of asthma [2] and is probably no more frequent than in children with other incapacitating physical illness [3]. A 15-year follow-up study [4] has failed to show any difference between a group of asthmatics in the community and matched controls with regard to either period prevalence or diagnoses of mental illness. The occurrence of mental illness in those with a history of asthma was not related to the prognosis for asthma. Although the follow-up study had the advantage of investigating mental health over a prolonged period, the methods of assessment were essentially crude and may have been too insensitive to identify valid differences between asthmatics and controls. It has therefore been supplemented with data from an investigation of the respiratory and mental state at the time of follow-up (i.e. at the end of the 15-year period. These data for point prevalence are based on more detailed standardised assessments of both physical and mental state.
more
METHOD The potential subjects for this study consisted of the 55 asthma and 55 control probands from the earlier investigations, and the criteria for their selection have previously been described [l, 4, 51. Particularly relevant to the present study is the fact that they were not selected on the basis of referral for physical or mental illness. Of these subjects only those who were available for interview at the time *This investigation was partly carried out whilst working at the Institute of Psychiatry, University of London and was supported by a Bethlem Research Fund Grant. tDepartment of Psychiatry, University of Manchester, Swinton Grove, Manchester Ml3 OEU, England. 471
472
SIDNEYBENJAMIN
N
TABLE1.--POTENTIALSUBJECTS OMITTED Asthma Control 55 55
Traced dead Domiciled abroad Otherwise not available Untraced Total Traced vs untraced: = 1, not significant.
2 4 0 2 8
3
I
3 5 12 x*=0*550, degree of freedom
of follow-up could be included. Table 1 shows the reasons for loss of subjects from either group. Although more control group subjects were lost from the present study the difference is not statistically significant. Amongst those control subjects were three who were traced, surviving and domiciled within the U.K. but could not be personally interviewed. Two of these had a history of psychopathy and imprisonment or borstal training. The third had a history of problems with interpersonal relationships and poor work record. It is therefore possible that the loss of these subjects from the study may have biased the findings in favour of a relative excess of psychiatric disability in the asthma group. Table 2 shows demographic data for those subjects included in the present study. The two groups are well matched with regard to age, sex, marital and socio-economic status. TABLE2.-MATCHING OF SUBJECTS N Age SSX Marital status Socio-economic
: Mean Standard error : Male Female : Single Married Widowed/divorced status: I and II III IV and V Not applicable
Asthma 47 39.17 2.17 20 27 7 34 6 14 24 4 5
Control 43 38.42 2.32 18 25 9 28 6 14 25 2 2
All differences between groups not significant. All subjects were visited in their homes where an assessment of their current mental and physical state was carried out. The assessment of mental health was based on a standardised psychiatric interview [6] which is designed particularly for use in community surveys by trained psychiatrists and is known to have high inter-rater reliability. It relates to the seven days preceding the interview and provides ratings on five-point scales for 11 symptoms and 12 manifest abnormalities (Table 3). These ratings differentiate not only the presence or absence of each abnormality but also whether, if present, it represents a habitual personality trait or a morbid change of clinical significance. These ratings can be used as an individual symptom profile and also to provide a total score (twice the sum of the ratings for manifest abnormalities plus the sum of the symptom ratings). The standardised interview also includes an overall rating of severity (five-point scale), an assessment of the reliability of information given by the subject (three-point scale), a diagnosis based on the International Class&ation of Disease and a clinical formulation which draws on other available information (nast and family history, social history, other informants). The assessment of physical health included a standardised interview which was based on available contemporary questionnaires designed for use in research into respiratory disease [7, 81. It assessed the presence of asthma, chronic bronchitis and other pulmonary disorders in the preceding year, the severity of asthma in the preceding month, other aspects of the history of asthma including treatment, and details of smoking habits. The Expiratory Peak Flow Rate (PFR) was measured using a standard technique and converted into percentage of expected Peak Flow Rate (% PFR) based on tables of normal data and allowing for sex, age and height [9]. A study of bias in psychiatric assessment arising from the interviewer’s knowledge of the subjects’ status as asthmatic or control was carried out by audio tape-recording six consecutive interviews. Any
Is asthma a psychosomatic TABLE %--SYMPTOMS
AND
MANIFEST
ABNORMALITIES
473
illness?-II ASSESSED BY
PSYCHIATRICINTERVIEW
symptoms
Somatic symptoms of psychogenic origin Fatigue Sleep disturbance Use of hypnotics Irritability Lack of concentration Depression of mood Anxiety Phobias Obsessions and compulsions Depersonalisation Manifest Abrwrmalities
Slow, lacking spontaneity Suspicious, defensive Histrionic Depressed mood Anxious, agitated, tense Elated, euphoric Flattened, incongruous Delusions, thought disorder, misinterpretations Hallucinations Intellectual impairment Excessive concern with bodily functions Depressive thought content clues as to the subjects’ status were removed from the recordings and the interviews were then rated by a second psychiatrist trained in the use of the standardised interview. Although the lack of visual clues available to the second rater might have decreased inter-rater reliability, there is evidence that there is little difference in such reliability between audio-visual and audio recordings [lo]. RESULTS (i) Symptoms and manifest abnormalities A comparison of ratings of symptoms and manifest abnormalities between asthmatics and control groups included Student’s t-tests for differences between mean and distribution of ratings and x* tests for ‘goodness of fit’ for distribution of ratings. These analyses were carried out for both sexes separately and jointly. Detailed results are available [4] and only those results which approach statistically significant levels are presented here. For both sexes together, the only symptom showing a difference in mean ratings approaching significance is ‘fatigue’ (asthma: mean=0.66, S.E.=O.ll; control: mean=0.37, S.E.=O.lO; t=1*86, p cO.10). A total of 22 asthma subjects had a positive rating for fatigue compared with 11 control subjects (x2=3.496, degree of freedom=l, p
Mean
Control N=43 S.E.
86.47 96,84
;I;;
9264
2.38
VALUES
t t=2.26*
>
2’25* 4.13t 4.63t
*p co.05 tp 2
IO 14
8 10
3 2
__
‘Somatic symptoms’ Asthma in last year: Absent Present Control
>
N.S. >
Asthma in last month: Absent Present Control Predicted P.F.R. (asthma group): -180% _-80x ‘Manifest ansiet.y Asthma in last year: Absent Present Control Asthma in last month: Absent Present Control Predicted P.F.R. (asthma group): 80% d.f. =Degrees of freedom. N.S. -Not significant.
21 26
x2=5.183, d.f.=2, p (0.10
x2=6.161, d.f.==2, p (0.05
3 5
4
N.S.
x2=6.638, d.f.=2, p co.05 1
x”=7.193, d.f.-2, >
p x0.02
x2= 12.062, d.f.=2, p
of Psychmomatic
Research,
IS ASTHMA A COMPARATIVE
Vol.
21, pp.
471 to 481.
Pergamon
Press.
A PSYCHOSOMATIC STUDY OF RESPIRATORY MENTAL HEALTH*
1977.
Printed
in Great
Britain
ILLNESS?-II. IMPAIRMENT
AND
SIDNEY BENJAMINt (Received
14 June 1977)
Abstract-The respiratory state and mental health of a group of 47 asthmatics and 43 matched non-asthmatic controls have been compared using standardised interview and respiratory function assessments. Despite physical impairment the asthma group failed to show any significant excess in point prevalence, or any difference in the diagnostic categories of mental illness suffered. There was a tendency for more positive ratings for psychopathology to be made for the asthma group but this was not related to greater physiological impairment. It is suggested that this trend arises mainly due to overreporting of symptoms of all kinds by some members of the asthma group. These results are considered in the light of similar findings in others with respiratory disorder. The importance of bias arising from selection of subjects in research into somatic and psychic relationships is emphasised and the implications for clinical management are discussed.
THE NATURE of the association between asthma and mental illness the management of asthma and for the concept of psychosomatic reports matics
suggested that neurotic and that schizophrenia
is of interest both for illness. Many earlier
disorders are more common than is less common and may alternate
expected in asthwith asthma, but
recent studies fail to support these views. An excess of neurotic illness in asthmatics appears to be limited to disorders in children [l]; is related to the severity of asthma [2] and is probably no more frequent than in children with other incapacitating physical illness [3]. A 15-year follow-up study [4] has failed to show any difference between a group of asthmatics in the community and matched controls with regard to either period prevalence or diagnoses of mental illness. The occurrence of mental illness in those with a history of asthma was not related to the prognosis for asthma. Although the follow-up study had the advantage of investigating mental health over a prolonged period, the methods of assessment were essentially crude and may have been too insensitive to identify valid differences between asthmatics and controls. It has therefore been supplemented with data from an investigation of the respiratory and mental state at the time of follow-up (i.e. at the end of the 15-year period. These data for point prevalence are based on more detailed standardised assessments of both physical and mental state.
more
METHOD The potential subjects for this study consisted of the 55 asthma and 55 control probands from the earlier investigations, and the criteria for their selection have previously been described [l, 4, 51. Particularly relevant to the present study is the fact that they were not selected on the basis of referral for physical or mental illness. Of these subjects only those who were available for interview at the time *This investigation was partly carried out whilst working at the Institute of Psychiatry, University of London and was supported by a Bethlem Research Fund Grant. tDepartment of Psychiatry, University of Manchester, Swinton Grove, Manchester Ml3 OEU, England. 471
472
SIDNEYBENJAMIN
N
TABLE1.--POTENTIALSUBJECTS OMITTED Asthma Control 55 55
Traced dead Domiciled abroad Otherwise not available Untraced Total Traced vs untraced: = 1, not significant.
2 4 0 2 8
3
I
3 5 12 x*=0*550, degree of freedom
of follow-up could be included. Table 1 shows the reasons for loss of subjects from either group. Although more control group subjects were lost from the present study the difference is not statistically significant. Amongst those control subjects were three who were traced, surviving and domiciled within the U.K. but could not be personally interviewed. Two of these had a history of psychopathy and imprisonment or borstal training. The third had a history of problems with interpersonal relationships and poor work record. It is therefore possible that the loss of these subjects from the study may have biased the findings in favour of a relative excess of psychiatric disability in the asthma group. Table 2 shows demographic data for those subjects included in the present study. The two groups are well matched with regard to age, sex, marital and socio-economic status. TABLE2.-MATCHING OF SUBJECTS N Age SSX Marital status Socio-economic
: Mean Standard error : Male Female : Single Married Widowed/divorced status: I and II III IV and V Not applicable
Asthma 47 39.17 2.17 20 27 7 34 6 14 24 4 5
Control 43 38.42 2.32 18 25 9 28 6 14 25 2 2
All differences between groups not significant. All subjects were visited in their homes where an assessment of their current mental and physical state was carried out. The assessment of mental health was based on a standardised psychiatric interview [6] which is designed particularly for use in community surveys by trained psychiatrists and is known to have high inter-rater reliability. It relates to the seven days preceding the interview and provides ratings on five-point scales for 11 symptoms and 12 manifest abnormalities (Table 3). These ratings differentiate not only the presence or absence of each abnormality but also whether, if present, it represents a habitual personality trait or a morbid change of clinical significance. These ratings can be used as an individual symptom profile and also to provide a total score (twice the sum of the ratings for manifest abnormalities plus the sum of the symptom ratings). The standardised interview also includes an overall rating of severity (five-point scale), an assessment of the reliability of information given by the subject (three-point scale), a diagnosis based on the International Class&ation of Disease and a clinical formulation which draws on other available information (nast and family history, social history, other informants). The assessment of physical health included a standardised interview which was based on available contemporary questionnaires designed for use in research into respiratory disease [7, 81. It assessed the presence of asthma, chronic bronchitis and other pulmonary disorders in the preceding year, the severity of asthma in the preceding month, other aspects of the history of asthma including treatment, and details of smoking habits. The Expiratory Peak Flow Rate (PFR) was measured using a standard technique and converted into percentage of expected Peak Flow Rate (% PFR) based on tables of normal data and allowing for sex, age and height [9]. A study of bias in psychiatric assessment arising from the interviewer’s knowledge of the subjects’ status as asthmatic or control was carried out by audio tape-recording six consecutive interviews. Any
Is asthma a psychosomatic TABLE %--SYMPTOMS
AND
MANIFEST
ABNORMALITIES
473
illness?-II ASSESSED BY
PSYCHIATRICINTERVIEW
symptoms
Somatic symptoms of psychogenic origin Fatigue Sleep disturbance Use of hypnotics Irritability Lack of concentration Depression of mood Anxiety Phobias Obsessions and compulsions Depersonalisation Manifest Abrwrmalities
Slow, lacking spontaneity Suspicious, defensive Histrionic Depressed mood Anxious, agitated, tense Elated, euphoric Flattened, incongruous Delusions, thought disorder, misinterpretations Hallucinations Intellectual impairment Excessive concern with bodily functions Depressive thought content clues as to the subjects’ status were removed from the recordings and the interviews were then rated by a second psychiatrist trained in the use of the standardised interview. Although the lack of visual clues available to the second rater might have decreased inter-rater reliability, there is evidence that there is little difference in such reliability between audio-visual and audio recordings [lo]. RESULTS (i) Symptoms and manifest abnormalities A comparison of ratings of symptoms and manifest abnormalities between asthmatics and control groups included Student’s t-tests for differences between mean and distribution of ratings and x* tests for ‘goodness of fit’ for distribution of ratings. These analyses were carried out for both sexes separately and jointly. Detailed results are available [4] and only those results which approach statistically significant levels are presented here. For both sexes together, the only symptom showing a difference in mean ratings approaching significance is ‘fatigue’ (asthma: mean=0.66, S.E.=O.ll; control: mean=0.37, S.E.=O.lO; t=1*86, p cO.10). A total of 22 asthma subjects had a positive rating for fatigue compared with 11 control subjects (x2=3.496, degree of freedom=l, p
Mean
Control N=43 S.E.
86.47 96,84
;I;;
9264
2.38
VALUES
t t=2.26*
>
2’25* 4.13t 4.63t
*p co.05 tp 2
IO 14
8 10
3 2
__
‘Somatic symptoms’ Asthma in last year: Absent Present Control
>
N.S. >
Asthma in last month: Absent Present Control Predicted P.F.R. (asthma group): -180% _-80x ‘Manifest ansiet.y Asthma in last year: Absent Present Control Asthma in last month: Absent Present Control Predicted P.F.R. (asthma group): 80% d.f. =Degrees of freedom. N.S. -Not significant.
21 26
x2=5.183, d.f.=2, p (0.10
x2=6.161, d.f.==2, p (0.05
3 5
4
N.S.
x2=6.638, d.f.=2, p co.05 1
x”=7.193, d.f.-2, >
p x0.02
x2= 12.062, d.f.=2, p
