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The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes a
a
a
b
Dafna Weis M.A. , Lee Rothenberg B.A. , Lital Moshe B.A. , David A. Brent M.D. & Sami a
Hamdan Ph.D. a
School of Behavioral Sciences, The Academic College of Tel-Aviv Jaffa (MTA), Israel
b
Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA Accepted author version posted online: 17 Dec 2014.
Click for updates To cite this article: Dafna Weis M.A., Lee Rothenberg B.A., Lital Moshe B.A., David A. Brent M.D. & Sami Hamdan Ph.D. (2014): The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes, Archives of Suicide Research, DOI: 10.1080/13811118.2014.986697 To link to this article: http://dx.doi.org/10.1080/13811118.2014.986697
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to this version also.
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes Dafna Weis1, Lee Rothenberg1, Lital Moshe1, David A. Brent2, Sami Hamdan1 1
School of Behavioral Sciences, The Academic College of Tel-Aviv Jaffa (MTA), Israel Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA
2
For correspondence, please contact Sami Hamdan, P.O.B. 8401, Tel-Aviv-Jaffa, 61083, Israel E-mail: [email protected]
Downloaded by [FU Berlin] at 06:03 12 May 2015
Abstract We aimed to investigate the effect of sleep problems, depression, and cognitive processes on suicidal risk among 460 young adults. They completed self-report questionnaires assessing suicidal behavior, sleep quality, depressive symptoms, emotion regulation, rumination, and Impulsivity. Suicidal participants exhibited higher rates of depressive symptoms, sleep problems, expressive suppression, rumination, and impulsivity. A confirmatory factor analysis model revealed pathways to suicidal risk that showed no direct pathways between sleep problems and suicidal risk. Instead, sleep was related to suicidal risk via depression and rumination, which in turn increased suicidal risk. These results suggest that addressing sleep problems will be useful in either the treatment or prevention of depressive and rumination symptoms and reduction in suicidal risk.
KEYWORDS: Suicidal risk; sleep problems; depression; rumination
INTRODUCTION
1
Approximately 1 million people worldwide die each year by suicide, making it one of the leading causes of death (Cash & Bridge, 2009; Centers for Disease Control and Prevention, 2013; Nock et al., 2008). Therefore, there is an urgent need to identify risk factors that will help clinicians more accurately identify individuals who are at risk of suicide, as well as to help develop new treatments to prevent suicide.
One growing area of research includes the study of sleep in suicidal behaviors. Strong
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associations between sleep problems and suicidal behaviors have been reported. Insomnia symptoms have been found to be positively associated with suicidal ideation among adolescents (Barbe et al., 2005; Roberts et al., 2001; Wong et al, 2011; Wong & Brower, 2012) and adults (Betts et al, 2013; Chakravorty et al., 2014; Cukrowicz et al., 2006; Gunnell et al., 2013; Krakow et al., 2011; Nadorff, Nazem & Fiske, 2011; Nadorff et al., 2013a; Pigeon et al., 2012; Ribeiro et al., 2012; Wojnar et al., 2009). In addition, insomnia symptoms have been associated with suicide attempts (Bailly et al, 2004; Hall et al, 1999; Nrugham et al, 2008) and with death by suicide (Fawcett et al., 1990; Goldstein, Bridge & Brent, 2008; Bjørngaard et al., 2011). Furthermore, nightmares have also found related to suicidal ideation in clinical (Agargun et al., 1998; Bernert et al., 2005; Krakow et al., 2011 Liu, 2004), as well as in community samples (Nadorff et al., 2013c; Nrugham et al., 2008). Sjöström and colleagues (2009) found that medically serious suicide attempters who reported persistent nightmares in the last 2 years before the interview were at more than four times greater risk of re-attempting suicide than those who did not report having nightmares. Other types of sleep problems including
2
hypersomnia have also been found to be related to suicidal behaviors (Agargun et al., 1997; Blasco-Fontecilla et al., 2011; Bae et al. 2013).
While the literature is now replete with studies showing strong associations between sleep problems and suicidal risk, there has been less attention to the processes and mechanisms by which sleep problems increase suicidal risk. There are a number of candidate explanators. First, sleep disturbance is a common symptom of psychiatric
Downloaded by [FU Berlin] at 06:03 12 May 2015
illness, which in turn is among the most important risk factors for suicide (Cavanagh et al., 2003; Gunnell & Lewis, 2005). Therefore it may be psychiatric illness, rather than sleep disturbance, that predisposes the sleep-suicide association. Indeed, relatively many studies found that the relation between insomnia and suicidal ideation is mediated by depression (Bernert et al., 2005; Cukrowicz et al., 2006; Liu, 2004; Nadorff et al., 2013b; Szklo-Coxe et al., 2010). Second, the relation between sleep problems and suicide may be confounded common correlates or sequelae of sleep disturbance, namely emotional dys-regulation (specifically: expressive suppression) (Kaplow, Gipson, Horwitz, Burch & King, 2013), increased impulsivity and/or aggressiveness (Dahl & Lewin, 2002; Gvion & Apter, 2011; Zouk, Tousignant, Seguin, Lesage, & Turecki, 2006) drug and alcohol abuse (Bjørngaard et al., 2011; Shoval et al., 2013), or disturbance in problem-solving ability (Harrison and Horne, 2000; Kohyama, 2010; Mckenna et al., 2007; Venkatraman et al., 2007).
On the other hand, several studies that found a robust and direct relation between sleep problems and suicidal behavior both in adolescents and adults, may suggest an alternative
3
explanation that there are not intervening variables, but sleep has a direct effect on suicidal risk. For instance, Smith, Perlis and Haythornthwaite (2004), found that chronic pain patients who reported sleep-onset insomnia symptoms were significantly more likely to report suicidal ideation, independent from the effects of depression severity. Adults suicide attempters who reported persistent nightmares, compare with the suicide attempters without nightmares, were at greater risk of re-attempting suicide, even after adjusting for sex, any psychiatric disorder, and self-reported depressive or anxiety
Downloaded by [FU Berlin] at 06:03 12 May 2015
symptom (Sjöström,et al., 2009). Furthermore, among young adults in the military, insomnia symptoms continue to be associated with suicidal ideation even after controlling for symptoms of depression, hopelessness, anxiety, post-traumatic stress disorders (PTSD) diagnosis, and drug and alcohol abuse (Ribeiro et al., 2012). The insomnia – suicidal ideation relations were reported in other samples (Nadorff et al, 2011; Nadorff et al., 2013c) including adolescents (Liu, 2004). In an autopsy study among adolescent suicide completers, Goldstein and her colleagues (2008) found that even after controlling for differences in depressive symptoms, suicide completers experienced significantly more sleep difficulties than adolescents in a community control, as well as more insomnia or hypersomnia in the week prior to suicide completion.
Several limitations characterize the sleep-suicide studies, which in turn limit the ability to better understand the nature of the sleep-suicide relationship; most of the studies reported on clinical samples (inpatient or outpatient), and many of those that report on this relation in a community sample surveys were not designed to address the relation between sleep problems and suicidal behaviors. Moreover, the measurements of sleep problems in most
4
of the studies were based on single items rather than using validated self-report questionnaires or objective measurements of sleep problems indicators (Pigeon et al., 2012). In addition, the cognitive processes most relevant to suicidal behavior have received relatively little research attention and are not well understood (Miranda & Nolen-Hoeksema, 2007; Miranda & Shaffer, 2013). Rumination is a style of thinking characterized by recurrent, intrusive and un-controllable thoughts. It is characterized by dwelling on one's negative mood or engaging in cognitive appraisal processes to
Downloaded by [FU Berlin] at 06:03 12 May 2015
understand and change one's negative emotions (Brinker et al., 2013; McEvoy et al., 2013; Treynor et al., 2003). Rumination consists of two components, (1) brooding and (2) reflection. Brooding is repetitively dwelling on negative consequences of distress, whereas reflection involves actively seeking information in order to better understand one's distress (Miranda & Nolen-Hoeksema, 2007; Treynor et al., 2003). Rumination has been found related with both suicidal ideation (Miranda & Nolen-Hoeksema, 2007; Morrison and O'Connor, 2008; Smith, Alloy, & Abramson, 2006; Tucker et al., 2013) and sleep problems (Carney, Harris, Moss & Edinger, 2010; Kahn et al., 2013; Takano et al., 2012; Zawadzki et al., 2013).
Thus, the aim of this study was to examine the effect of various aspects of sleep problems on suicidal behaviors in a community sample of young adults. In addition, we aimed to explore the role of cognitive processes, namely; rumination and emotional regulation, on the relation of sleep problems and suicidal behaviors in the presence of depressive symptoms. In other words: to investigate the triadic relation between emotional
5
regulation, sleep and suicide, and the triadic relation between rumination, sleep and suicide.
METHOD Participants And Procedure Four hundred and sixty young adults individuals from a community convenience sample, (341 women and 119 men), aged 18–35 years (mean = 25.6; standard deviation (SD)
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=3.1), who agreed to take part in the research voluntarily and anonymously. They were recruited among the students of the different universities in Israel, others by an announcement in virtual social networks. Demographic characteristics are shown in Table 1. The study was approved by the ethical committee of Tel Aviv-Yaffo Academic College and participants provided informed consent for participation. At the conclusion of the survey, participants were shown a referral sheet with contact information for local mental health services, should they desire counseling following the study.
MEASURES The Suicidal Behaviors Questionnaire - Revised (SBQ-R; Osman et al., 2001). The SBQR, revised from the Suicidal Behaviors Questionnaire (Linehan, 1981), is a 4-item, Likert-style self-report measure designed to assess levels of suicidal risk. The first item measures levels of lifetime suicidal behaviors including thoughts, plans and attempts (i.e., ―Have you ever thought about or attempted to kill yourself?‖); the second item assesses the frequency of suicidal thoughts in the past year) i.e., ―How often have you thought about killing yourself in the past year?‖); the third item measures the communication of
6
the intent to commit suicide (i.e., ―Have you ever told someone that you were going to commit suicide, or that you might do it?‖) and the fourth item assesses the likelihood of committing suicide in the future (i.e., ―How likely is it that you will attempt suicide someday?‖). The total score ranges from 3 to 18 with higher scores indicating greater levels of suicidal behaviors and a cutoff score of 7 determine clinically significant levels of suicide risk. Osman et al. (2001) have shown that the questionnaire is a reliable research tool in both clinical and non-clinical samples with an alpha coefficient ranging
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from .76 to .88. The alpha coefficient in the present sample is .82.
The Pittsburgh Sleep Quality Index (PSQI; Buysse et al., 1989). The PSQI is a self-report measure of sleep quality, queries about multiple sleep-related variables over the preceding month, using likert and open-ended response formats. The PSQI yields seven components (i.e. subscale) scores: subjective sleep quality, sleep duration, habitual sleep efficiency, sleep latency, sleep disturbances, sleep medication, and daytime dysfunction. Component scores range from 0 to 3 and are summed to obtain a global score, which ranges from 0 to 21. Higher scores suggest greater sleep disturbance; a global score more than 5 suggests a significant disturbance. Since its introduction in 1989, the PSQI has gained widespread acceptance as a useful tool to measure sleep quality in different patient groups, and showed a high correlation to sleep diaries (Backhaus et al., 2002). Buysse et al. (1989) showed an overall reliability coefficient (Cronbach’s a) of .83. The alpha coefficient in the present sample is .70.
7
The Patient Health Questionnaire (PHQ, Spitzer et al., 1999). The measure of depression severity in the current study was assessed using the PHQ-9, a 9-item depression module from the full PHQ (Kroenke et al., 2010). The PHQ-9 component scores are range from 0 (not at all) to 3 (nearly every day), and are summed to obtain a global score, which ranges from 0 to 27. Cronbach's α was reported by developers to be .89 and .86 in the validation studies of the PHQ-9 (Kroenke et al., 2001). The alpha coefficient in the present sample is .82. The measure of anxiety severity in this study was assessed using
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the GAD-7 (General Anxiety disorder-7), a 7- items anxiety module from the full PHQ (Spitzer, et al; 2006).
The Response Style Questionnaire (RSQ) (Nolen-Hoeksema & Morrow, 1991). The RSQ is a 71-item self-report measure that assesses the level at which individuals engage in various cognitive coping styles. It has four subscales (rumination, distraction, problemsolving and dangerous activities), although only rumination responses subscale (RRQ, 22 items) were analyzed in this study. The RRQ assesses depressive rumination style with items such as ―Why do I always react this way?‖ The component scores range from 1 (never) to 4 (always), and are summed to obtain a global score, which ranges from 22 to 88 (Nolen-Hoeksema & Morrow, 1991). In addition to the original subscale, scores were also calculated for two specific styles of rumination: brooding and reflection, and for a combined variable (sum of the brooding & reflection scores), based on a more recent refinement 10-item scale module from the full RRQ (Treynor, Gonzales, & NolenHoeksema, 2003). Cronbach's α was reported to be .80 for Brooding and .72 for reflection (Treynor et al., 2003). In the current study the alpha's coefficient are .77 and .83 for
8
Brooding and reflecting respectively, and .88 for a combined Brooding-Reflection scale. In this study, we used the median score as cut off point and dichotomized this measure in order to report on frequencies of participants' exhibited ruminative style.
The Emotion Regulation Questionnaire (ERQ; Gross & John, 2003). The Emotion Regulation Questionnaire is a 10-item self-report questionnaire designed to measure the use of two emotion regulation strategies: 'cognitive reappraisal' (ERQ-R, 6 items), versus
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'expressive suppression' (ERQ-S, 4 items). Cognitive reappraisal is a form of antecedentfocused emotion regulation whereby the individual modifies his or her thoughts about a potential emotion-eliciting situation in order to alter its emotional impact (e.g., When I want to feel more positive emotion (such as joy or amusement, I change the way I’m thinking about the situation). Expressive suppression is a form of response focused emotion regulation whereby the individual inhibits his or her emotional expression once the emotion has been elicited (e.g., When I am feeling negative emotions, I make sure not to express them). The 10 items are rated on a 7-point-likert scale from strongly disagree to strongly agree. The scale has been shown to possess good psychometric properties (Gross & John, 2003). In the current study, and consistent with Gross and John, the ERQR and ERQ-S were independent, and Cronbach’s alphas were .85 and .78 for the ERQ-R and ERQ-S, respectively.
The Impulsivity Scale (IS, Plutchik & Van Praag, 1989). The Impulsivity Control Scale is a 15-item; self-report questionnaire designed to measure the tendency to engage in impulsive, spur-of-the-moment behaviors, all of which reflect possible losses of control.
9
The Impulsivity Scale (IS) component scores are range from 0 (never) to 3 (very often), and are summed to obtain a global score, which ranges from 0 to 45. Cronbach's α was reported by developers to be .73. In the present sample, the internal reliability of the IS is .78.
STATISTICAL METHODS The simple effects of study variables on suicidal ideation and behavior (Yes/No) were
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assessed by calculating odds ratios (OR). The simple effects of study variables on suicide scale were assessed by calculating Pearson correlations (r). Continuous variables are presented as mean± SD. Categorical variables are presented as N, %. Multivariate effects and interaction effects of study variables on suicide scale were assessed by fitting a multivariate linear regression model. Finally, confirmatory factor analyses were conducted using AMOS software (Arbuckle, 1997). Beginning with the variables identified by linear regression as the predictors of suicidal risk, we fit several models to identify potential pathways to suicidal risk. We used chi square, comparative fit index (CFI), Tucker-Lewis index (TLI) and Root Mean Square Residual (RMSR) statistics to assess goodness of fit. 92.4% of the sample had no missing data for any variable, 7.2% had missing data for 1 or 2 variables, and 0.4 % had missing data for 3 or 4 variables.
RESULTS Characteristics of the sample: 26% of 460 participants were males (N=119). The mean age was 25.6 years (SD=3.1) and the majority (84.6%) describe themselves as physically healthy. Using established clinical cut points on the PHQ-9 and GAD-7, about fifth of
10
sample (19.6%) reported moderate or severe depressive symptoms and 52.3% showed moderate or severe anxiety symptoms on the GAD-7. in addition, a total of 25 participants (6.4%) reported compulsive alcohol drinking. 11% of total sample, reported clinically significant suicidal risk (suicide Ideation with/without plans, or suicide attempts) (hence: suicidal participants). In addition, 34.3% of the total sample (158) reported high levels of rumination.
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As shown in Table 1, there were no significant differences between suicidal participants compare to non-suicidal in term of their age or gender. The suicidal participants had higher rates of depressive symptoms (46.9% vs. 16.1%, OR=4.79; 95% confidence interval [CI] 2.56-8.96; p
Archives of Suicide Research Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/usui20
The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes a
a
a
b
Dafna Weis M.A. , Lee Rothenberg B.A. , Lital Moshe B.A. , David A. Brent M.D. & Sami a
Hamdan Ph.D. a
School of Behavioral Sciences, The Academic College of Tel-Aviv Jaffa (MTA), Israel
b
Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA Accepted author version posted online: 17 Dec 2014.
Click for updates To cite this article: Dafna Weis M.A., Lee Rothenberg B.A., Lital Moshe B.A., David A. Brent M.D. & Sami Hamdan Ph.D. (2014): The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes, Archives of Suicide Research, DOI: 10.1080/13811118.2014.986697 To link to this article: http://dx.doi.org/10.1080/13811118.2014.986697
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to this version also.
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
The Effect of Sleep Problems on Suicidal Risk Among Young Adults in the Presence of Depressive Symptoms and Cognitive Processes Dafna Weis1, Lee Rothenberg1, Lital Moshe1, David A. Brent2, Sami Hamdan1 1
School of Behavioral Sciences, The Academic College of Tel-Aviv Jaffa (MTA), Israel Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA
2
For correspondence, please contact Sami Hamdan, P.O.B. 8401, Tel-Aviv-Jaffa, 61083, Israel E-mail: [email protected]
Downloaded by [FU Berlin] at 06:03 12 May 2015
Abstract We aimed to investigate the effect of sleep problems, depression, and cognitive processes on suicidal risk among 460 young adults. They completed self-report questionnaires assessing suicidal behavior, sleep quality, depressive symptoms, emotion regulation, rumination, and Impulsivity. Suicidal participants exhibited higher rates of depressive symptoms, sleep problems, expressive suppression, rumination, and impulsivity. A confirmatory factor analysis model revealed pathways to suicidal risk that showed no direct pathways between sleep problems and suicidal risk. Instead, sleep was related to suicidal risk via depression and rumination, which in turn increased suicidal risk. These results suggest that addressing sleep problems will be useful in either the treatment or prevention of depressive and rumination symptoms and reduction in suicidal risk.
KEYWORDS: Suicidal risk; sleep problems; depression; rumination
INTRODUCTION
1
Approximately 1 million people worldwide die each year by suicide, making it one of the leading causes of death (Cash & Bridge, 2009; Centers for Disease Control and Prevention, 2013; Nock et al., 2008). Therefore, there is an urgent need to identify risk factors that will help clinicians more accurately identify individuals who are at risk of suicide, as well as to help develop new treatments to prevent suicide.
One growing area of research includes the study of sleep in suicidal behaviors. Strong
Downloaded by [FU Berlin] at 06:03 12 May 2015
associations between sleep problems and suicidal behaviors have been reported. Insomnia symptoms have been found to be positively associated with suicidal ideation among adolescents (Barbe et al., 2005; Roberts et al., 2001; Wong et al, 2011; Wong & Brower, 2012) and adults (Betts et al, 2013; Chakravorty et al., 2014; Cukrowicz et al., 2006; Gunnell et al., 2013; Krakow et al., 2011; Nadorff, Nazem & Fiske, 2011; Nadorff et al., 2013a; Pigeon et al., 2012; Ribeiro et al., 2012; Wojnar et al., 2009). In addition, insomnia symptoms have been associated with suicide attempts (Bailly et al, 2004; Hall et al, 1999; Nrugham et al, 2008) and with death by suicide (Fawcett et al., 1990; Goldstein, Bridge & Brent, 2008; Bjørngaard et al., 2011). Furthermore, nightmares have also found related to suicidal ideation in clinical (Agargun et al., 1998; Bernert et al., 2005; Krakow et al., 2011 Liu, 2004), as well as in community samples (Nadorff et al., 2013c; Nrugham et al., 2008). Sjöström and colleagues (2009) found that medically serious suicide attempters who reported persistent nightmares in the last 2 years before the interview were at more than four times greater risk of re-attempting suicide than those who did not report having nightmares. Other types of sleep problems including
2
hypersomnia have also been found to be related to suicidal behaviors (Agargun et al., 1997; Blasco-Fontecilla et al., 2011; Bae et al. 2013).
While the literature is now replete with studies showing strong associations between sleep problems and suicidal risk, there has been less attention to the processes and mechanisms by which sleep problems increase suicidal risk. There are a number of candidate explanators. First, sleep disturbance is a common symptom of psychiatric
Downloaded by [FU Berlin] at 06:03 12 May 2015
illness, which in turn is among the most important risk factors for suicide (Cavanagh et al., 2003; Gunnell & Lewis, 2005). Therefore it may be psychiatric illness, rather than sleep disturbance, that predisposes the sleep-suicide association. Indeed, relatively many studies found that the relation between insomnia and suicidal ideation is mediated by depression (Bernert et al., 2005; Cukrowicz et al., 2006; Liu, 2004; Nadorff et al., 2013b; Szklo-Coxe et al., 2010). Second, the relation between sleep problems and suicide may be confounded common correlates or sequelae of sleep disturbance, namely emotional dys-regulation (specifically: expressive suppression) (Kaplow, Gipson, Horwitz, Burch & King, 2013), increased impulsivity and/or aggressiveness (Dahl & Lewin, 2002; Gvion & Apter, 2011; Zouk, Tousignant, Seguin, Lesage, & Turecki, 2006) drug and alcohol abuse (Bjørngaard et al., 2011; Shoval et al., 2013), or disturbance in problem-solving ability (Harrison and Horne, 2000; Kohyama, 2010; Mckenna et al., 2007; Venkatraman et al., 2007).
On the other hand, several studies that found a robust and direct relation between sleep problems and suicidal behavior both in adolescents and adults, may suggest an alternative
3
explanation that there are not intervening variables, but sleep has a direct effect on suicidal risk. For instance, Smith, Perlis and Haythornthwaite (2004), found that chronic pain patients who reported sleep-onset insomnia symptoms were significantly more likely to report suicidal ideation, independent from the effects of depression severity. Adults suicide attempters who reported persistent nightmares, compare with the suicide attempters without nightmares, were at greater risk of re-attempting suicide, even after adjusting for sex, any psychiatric disorder, and self-reported depressive or anxiety
Downloaded by [FU Berlin] at 06:03 12 May 2015
symptom (Sjöström,et al., 2009). Furthermore, among young adults in the military, insomnia symptoms continue to be associated with suicidal ideation even after controlling for symptoms of depression, hopelessness, anxiety, post-traumatic stress disorders (PTSD) diagnosis, and drug and alcohol abuse (Ribeiro et al., 2012). The insomnia – suicidal ideation relations were reported in other samples (Nadorff et al, 2011; Nadorff et al., 2013c) including adolescents (Liu, 2004). In an autopsy study among adolescent suicide completers, Goldstein and her colleagues (2008) found that even after controlling for differences in depressive symptoms, suicide completers experienced significantly more sleep difficulties than adolescents in a community control, as well as more insomnia or hypersomnia in the week prior to suicide completion.
Several limitations characterize the sleep-suicide studies, which in turn limit the ability to better understand the nature of the sleep-suicide relationship; most of the studies reported on clinical samples (inpatient or outpatient), and many of those that report on this relation in a community sample surveys were not designed to address the relation between sleep problems and suicidal behaviors. Moreover, the measurements of sleep problems in most
4
of the studies were based on single items rather than using validated self-report questionnaires or objective measurements of sleep problems indicators (Pigeon et al., 2012). In addition, the cognitive processes most relevant to suicidal behavior have received relatively little research attention and are not well understood (Miranda & Nolen-Hoeksema, 2007; Miranda & Shaffer, 2013). Rumination is a style of thinking characterized by recurrent, intrusive and un-controllable thoughts. It is characterized by dwelling on one's negative mood or engaging in cognitive appraisal processes to
Downloaded by [FU Berlin] at 06:03 12 May 2015
understand and change one's negative emotions (Brinker et al., 2013; McEvoy et al., 2013; Treynor et al., 2003). Rumination consists of two components, (1) brooding and (2) reflection. Brooding is repetitively dwelling on negative consequences of distress, whereas reflection involves actively seeking information in order to better understand one's distress (Miranda & Nolen-Hoeksema, 2007; Treynor et al., 2003). Rumination has been found related with both suicidal ideation (Miranda & Nolen-Hoeksema, 2007; Morrison and O'Connor, 2008; Smith, Alloy, & Abramson, 2006; Tucker et al., 2013) and sleep problems (Carney, Harris, Moss & Edinger, 2010; Kahn et al., 2013; Takano et al., 2012; Zawadzki et al., 2013).
Thus, the aim of this study was to examine the effect of various aspects of sleep problems on suicidal behaviors in a community sample of young adults. In addition, we aimed to explore the role of cognitive processes, namely; rumination and emotional regulation, on the relation of sleep problems and suicidal behaviors in the presence of depressive symptoms. In other words: to investigate the triadic relation between emotional
5
regulation, sleep and suicide, and the triadic relation between rumination, sleep and suicide.
METHOD Participants And Procedure Four hundred and sixty young adults individuals from a community convenience sample, (341 women and 119 men), aged 18–35 years (mean = 25.6; standard deviation (SD)
Downloaded by [FU Berlin] at 06:03 12 May 2015
=3.1), who agreed to take part in the research voluntarily and anonymously. They were recruited among the students of the different universities in Israel, others by an announcement in virtual social networks. Demographic characteristics are shown in Table 1. The study was approved by the ethical committee of Tel Aviv-Yaffo Academic College and participants provided informed consent for participation. At the conclusion of the survey, participants were shown a referral sheet with contact information for local mental health services, should they desire counseling following the study.
MEASURES The Suicidal Behaviors Questionnaire - Revised (SBQ-R; Osman et al., 2001). The SBQR, revised from the Suicidal Behaviors Questionnaire (Linehan, 1981), is a 4-item, Likert-style self-report measure designed to assess levels of suicidal risk. The first item measures levels of lifetime suicidal behaviors including thoughts, plans and attempts (i.e., ―Have you ever thought about or attempted to kill yourself?‖); the second item assesses the frequency of suicidal thoughts in the past year) i.e., ―How often have you thought about killing yourself in the past year?‖); the third item measures the communication of
6
the intent to commit suicide (i.e., ―Have you ever told someone that you were going to commit suicide, or that you might do it?‖) and the fourth item assesses the likelihood of committing suicide in the future (i.e., ―How likely is it that you will attempt suicide someday?‖). The total score ranges from 3 to 18 with higher scores indicating greater levels of suicidal behaviors and a cutoff score of 7 determine clinically significant levels of suicide risk. Osman et al. (2001) have shown that the questionnaire is a reliable research tool in both clinical and non-clinical samples with an alpha coefficient ranging
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from .76 to .88. The alpha coefficient in the present sample is .82.
The Pittsburgh Sleep Quality Index (PSQI; Buysse et al., 1989). The PSQI is a self-report measure of sleep quality, queries about multiple sleep-related variables over the preceding month, using likert and open-ended response formats. The PSQI yields seven components (i.e. subscale) scores: subjective sleep quality, sleep duration, habitual sleep efficiency, sleep latency, sleep disturbances, sleep medication, and daytime dysfunction. Component scores range from 0 to 3 and are summed to obtain a global score, which ranges from 0 to 21. Higher scores suggest greater sleep disturbance; a global score more than 5 suggests a significant disturbance. Since its introduction in 1989, the PSQI has gained widespread acceptance as a useful tool to measure sleep quality in different patient groups, and showed a high correlation to sleep diaries (Backhaus et al., 2002). Buysse et al. (1989) showed an overall reliability coefficient (Cronbach’s a) of .83. The alpha coefficient in the present sample is .70.
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The Patient Health Questionnaire (PHQ, Spitzer et al., 1999). The measure of depression severity in the current study was assessed using the PHQ-9, a 9-item depression module from the full PHQ (Kroenke et al., 2010). The PHQ-9 component scores are range from 0 (not at all) to 3 (nearly every day), and are summed to obtain a global score, which ranges from 0 to 27. Cronbach's α was reported by developers to be .89 and .86 in the validation studies of the PHQ-9 (Kroenke et al., 2001). The alpha coefficient in the present sample is .82. The measure of anxiety severity in this study was assessed using
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the GAD-7 (General Anxiety disorder-7), a 7- items anxiety module from the full PHQ (Spitzer, et al; 2006).
The Response Style Questionnaire (RSQ) (Nolen-Hoeksema & Morrow, 1991). The RSQ is a 71-item self-report measure that assesses the level at which individuals engage in various cognitive coping styles. It has four subscales (rumination, distraction, problemsolving and dangerous activities), although only rumination responses subscale (RRQ, 22 items) were analyzed in this study. The RRQ assesses depressive rumination style with items such as ―Why do I always react this way?‖ The component scores range from 1 (never) to 4 (always), and are summed to obtain a global score, which ranges from 22 to 88 (Nolen-Hoeksema & Morrow, 1991). In addition to the original subscale, scores were also calculated for two specific styles of rumination: brooding and reflection, and for a combined variable (sum of the brooding & reflection scores), based on a more recent refinement 10-item scale module from the full RRQ (Treynor, Gonzales, & NolenHoeksema, 2003). Cronbach's α was reported to be .80 for Brooding and .72 for reflection (Treynor et al., 2003). In the current study the alpha's coefficient are .77 and .83 for
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Brooding and reflecting respectively, and .88 for a combined Brooding-Reflection scale. In this study, we used the median score as cut off point and dichotomized this measure in order to report on frequencies of participants' exhibited ruminative style.
The Emotion Regulation Questionnaire (ERQ; Gross & John, 2003). The Emotion Regulation Questionnaire is a 10-item self-report questionnaire designed to measure the use of two emotion regulation strategies: 'cognitive reappraisal' (ERQ-R, 6 items), versus
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'expressive suppression' (ERQ-S, 4 items). Cognitive reappraisal is a form of antecedentfocused emotion regulation whereby the individual modifies his or her thoughts about a potential emotion-eliciting situation in order to alter its emotional impact (e.g., When I want to feel more positive emotion (such as joy or amusement, I change the way I’m thinking about the situation). Expressive suppression is a form of response focused emotion regulation whereby the individual inhibits his or her emotional expression once the emotion has been elicited (e.g., When I am feeling negative emotions, I make sure not to express them). The 10 items are rated on a 7-point-likert scale from strongly disagree to strongly agree. The scale has been shown to possess good psychometric properties (Gross & John, 2003). In the current study, and consistent with Gross and John, the ERQR and ERQ-S were independent, and Cronbach’s alphas were .85 and .78 for the ERQ-R and ERQ-S, respectively.
The Impulsivity Scale (IS, Plutchik & Van Praag, 1989). The Impulsivity Control Scale is a 15-item; self-report questionnaire designed to measure the tendency to engage in impulsive, spur-of-the-moment behaviors, all of which reflect possible losses of control.
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The Impulsivity Scale (IS) component scores are range from 0 (never) to 3 (very often), and are summed to obtain a global score, which ranges from 0 to 45. Cronbach's α was reported by developers to be .73. In the present sample, the internal reliability of the IS is .78.
STATISTICAL METHODS The simple effects of study variables on suicidal ideation and behavior (Yes/No) were
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assessed by calculating odds ratios (OR). The simple effects of study variables on suicide scale were assessed by calculating Pearson correlations (r). Continuous variables are presented as mean± SD. Categorical variables are presented as N, %. Multivariate effects and interaction effects of study variables on suicide scale were assessed by fitting a multivariate linear regression model. Finally, confirmatory factor analyses were conducted using AMOS software (Arbuckle, 1997). Beginning with the variables identified by linear regression as the predictors of suicidal risk, we fit several models to identify potential pathways to suicidal risk. We used chi square, comparative fit index (CFI), Tucker-Lewis index (TLI) and Root Mean Square Residual (RMSR) statistics to assess goodness of fit. 92.4% of the sample had no missing data for any variable, 7.2% had missing data for 1 or 2 variables, and 0.4 % had missing data for 3 or 4 variables.
RESULTS Characteristics of the sample: 26% of 460 participants were males (N=119). The mean age was 25.6 years (SD=3.1) and the majority (84.6%) describe themselves as physically healthy. Using established clinical cut points on the PHQ-9 and GAD-7, about fifth of
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sample (19.6%) reported moderate or severe depressive symptoms and 52.3% showed moderate or severe anxiety symptoms on the GAD-7. in addition, a total of 25 participants (6.4%) reported compulsive alcohol drinking. 11% of total sample, reported clinically significant suicidal risk (suicide Ideation with/without plans, or suicide attempts) (hence: suicidal participants). In addition, 34.3% of the total sample (158) reported high levels of rumination.
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As shown in Table 1, there were no significant differences between suicidal participants compare to non-suicidal in term of their age or gender. The suicidal participants had higher rates of depressive symptoms (46.9% vs. 16.1%, OR=4.79; 95% confidence interval [CI] 2.56-8.96; p
