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Table of Contents
Year : 2022  |  Volume : 36  |  Issue : 1  |  Page : 25-31

Childhood trauma and sleep-related daytime dysfunction in patients with bipolar II disorder: Is social support a factor?

1 Department of Psychiatry, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
2 Department of Psychiatry, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
3 Department of Psychiatry, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University; Department of Psychiatry, Tainan Hospital, Ministry of Health and Welfare, Tainan, Taiwan

Date of Submission22-Sep-2021
Date of Decision10-Nov-2021
Date of Acceptance12-Nov-2021
Date of Web Publication26-Mar-2022

Correspondence Address:
Po See Chen
No 138, Sheng Li Road, North District
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/TPSY.TPSY_4_22

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Background: Sleep quality is an important predictor for prognosis of bipolar disorder (BD). Factors associated with sleep quality in BD such as childhood trauma experience merit investigation. Methods: We used the Pittsburgh Sleep Quality Index (PSQI), Childhood Trauma Questionnaire (CTQ), and Measurement of Support Functions (MSF) to access patients with BD-I (n = 31), and those with BD-II (n = 34). Results: We found that 71.4% of patients with BD-I and 90.9% of those with BD-II had poor sleep quality. Significantly higher CTQ physical abuse score and poor life quality were found among patients with BD-II (b = −0.008, Wald χ2 (1) = 5.024, p < 0.05). This effect remained robust (b = −0.012, Wald χ2 (1) = 8.150, p < 0.01) after controlling the use of drug (sedative, benzodiazepine, antipsychotic, and antidepressant). Moreover, the experience of childhood trauma was associated with poor sleep quality among patients with BD-II. A buffer effect of social support between physical abuse and daytime dysfunction, as measured by PSQI, was found in patients with BD-II, but not in those with BD-I. Conclusion: Social adversity and support were associated with sleep quality in patients with BD-II. This finding implied a stress-buffering model in patients with BD-II. But the underlying biological mechanism remains unclear.

Keywords: Childhood Trauma Questionnaire, child abuse, World Health Organization Quality of Life, Pittsburgh Sleep Quality Index

How to cite this article:
Lu TH, Hsieh YT, Lin SH, Yang YK, Chen PS. Childhood trauma and sleep-related daytime dysfunction in patients with bipolar II disorder: Is social support a factor?. Taiwan J Psychiatry 2022;36:25-31

How to cite this URL:
Lu TH, Hsieh YT, Lin SH, Yang YK, Chen PS. Childhood trauma and sleep-related daytime dysfunction in patients with bipolar II disorder: Is social support a factor?. Taiwan J Psychiatry [serial online] 2022 [cited 2022 Dec 3];36:25-31. Available from: http://www.e-tjp.org/text.asp?2022/36/1/25/341036

  Introduction Top

Sleep plays a vital rôle in patients with bipolar disorder (BD), with diagnostic criteria for sleep disturbances in both the manic and depressive episodes. According to published reports, 23%–78% of patients with BD depressive episode experience hypersomnia [1], and 48%–69% of them experience insomnia [2]. Compared to healthy persons, patients with BD manic episode have shorter rapid eye movement (REM) latency, increased REM density, increased REM activity, shorter sleep duration, and later sleep onset [1]. But no remarkable consensus exists in those psychognomonics in patients with BD depressive episode. Among patients with BD, insomnia has been found to be associated with bipolar II (BD-II) depression and hypersomnia with bipolar I (BD-I) depression or euthymia [2]. In a meta-analysis paper, patients in remitted BD have shown to have longer sleep latency, shorter sleep duration, longer wake time after sleep onset, and poor sleep efficiency [3]. In another study, patients in remitted BD have also been found to have more night-to-night variability of the sleep pattern [4]. The above studies implied that patients with BD have different sleeping disturbances regardless of episode and type compared to those in healthy controls.

More importantly, BD and sleep disturbances interact in bidirectional ways. The relapse of BD can cause sleep disturbances, and sleep disturbances can adversely affect BD symptoms. Moreover, the sleep disturbances are associated with cognitive deficit in patients with BD. One study indicated that patients with BD with sleep disturbances have deficits in cognitive function, including attention and processing speed, compared with those with BD with normal sleep and healthy control group [5].

Meanwhile, childhood trauma has been found to be associated with sleep disturbances in BD patients [6]. High prevalence of childhood trauma has been found among patients with BD who have the poor clinical course, such as early onset [7], and other wide range of negative outcomes [8]. On the other hand, supportive social environment can keep the brain more resilient from the change of neural substrate, resulting in reducing risks of psychiatric disease [9]. Social support helps people stay mentally healthy in stressful situations [10],[11]. The direct effect of social support itself can promote health regardless of the magnitude of stressor [12]. In general population, social support can also improve sleep quality [13], being possibly related to the effect of stress and emotional modulation [14].

The protective effect of social support on sleep quality in BD patients with childhood trauma remains unclear [14]. In this study, we intended to probe into the impact of childhood traumas on sleep quality in patients with BD, and to test whether social support can buffer the effect of childhood traumas on sleep quality in patients with BD.

  Methods Top

Study participants

We recruited patients with BD (31 with BD-I and 34 with BD-II) who had received mood stabilizer treatment at the psychiatry clinic at National Cheng Kung University Hospital. The institutional review board at National Cheng Kung University Hospital approved the study protocol (IRB protocol number = B-BR-107-032 and date of approval = August 20, 2018), requiring to obtain a signed written informed consent from all study participants.

Inclusion and exclusion criteria of study participants

We enrolled patients who were diagnosed with BD according to the DSM-5 [15] criteria by a senior psychiatrist, and who received mood stabilizer treatment. Those enrolled patients with BD had the age between 18 and 70 years. A senior psychiatrist evaluated patients' psychopathology with the Hamilton Depression Rating Scale and the Young Mania Rating Scale. Patients were excluded if they had (a) the diagnosis of mood disorder with neurocognitive symptoms, (b) a mood disorder not otherwise specified, or (c) more than one lifetime course of electroconvulsive therapy (ECT) or ECT within the last six months, (d) cerebrovascular disease, (e) neurodegenerative disorders, or (f) macrovascular disorders.

Although BD-I and BD-II are pooled as one homogeneous group, but BD-I and BD-II have different diagnostic criteria and prognoses [16],[17]. Therefore, we stratified our patients with BD into two distinct groups (i.e., BD-I and BD-II) in our analysis. Also, because sedative medications before sleep influence the sleep quality, we identified the sedative medications such as benzodiazepines, sedative antipsychotics, sedative mood stabilizers, and sedative antidepressants, and compared those medications between BD-I and BD-II.

Study instruments

Chinese version of the Pittsburgh Sleep Quality Index

The Pittsburgh Sleep Quality Index (PSQI) is a self-administered questionnaire used to evaluate patients' sleep quality during the previous month [18]. It contains 19 self-rated questions, yielding seven components – subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbances, use of sleep medications, and daytime dysfunction. Each component is scored on a scale of 0 to 3, yielding a global PSQI score ranging between 0 and 21, with higher scores indicating a poorer quality of sleep. A global PSQI score over 5 indicates a poor sleeper. This questionnaire has a diagnostic sensitivity of 90% and a specificity of 87% in distinguishing between good and poor sleepers [18]. The Chinese version of the PSQI has been reported as reliable and valid [19], and the internal consistency (Cronbach's a) of the PSQI for this sample was 0.66 in our institution. The higher the score, the poorer the sleeping.

Measurement of social functions

We used the self-reported Measurement of Support Functions (MSF) questionnaire [20], to quantify the level of social support each participant received. Higher MSF scores indicate more social support. The MSF has two dimensions of social support evaluation. One dimension represents the perceived versus received social support, whereas the other one represents the social support received under routine versus crisis conditions. Perceived support refers to the patient's perception of the availability of support when needed, and an appraisal of the adequacy and quality of such support. Received support refers to the nature and frequency of specific support transactions actually received in real situations. Perceived support thus focuses on subjective impressions of such support, while received support is a more objective measure. These two aspects of social support are not highly correlated, and show different patterns of association with distress [21]. Support under routine conditions shows either the support received or perceived relative to daily activities. Support in crisis conditions refers to the support perceived or received in an emergency situation. This two-dimensional questionnaire thus constitutes four 10-item subscales – perceived crisis support, perceived routine support, received crisis support, and received routine support. This validity of this instrument in Taiwan is supported by previous studies [22]. The two subscales have sound internal consistencies (i.e., Cronbach's alpha for perceived support under routine situations was 0.82, and Cronbach's alpha for perceived support under crisis was 0.68), and were significantly associated (r = 0.43, p < 0.01). Cronbach's alpha of the total 20 items was 0.83. The higher the score, the better the social support.

Childhood Trauma Questionnaire

The Childhood Trauma Questionnaire (CTQ) has five subtypes – emotional abuse, emotional neglect, physical abuse, physical neglect, and sexual abuse [23],[24]. Each item is rated on a 1–5-point scale, ranging from “never true when you were growing up” to “very often true when you were growing up.” Scores are ranged from 5 to 25 for each type of negative childhood experience. The higher the score, the more negative childhood trauma the participants report to have experienced. We used “none/minimal” to “low-to-moderate” cutoff scores to represent the absence and the presence of childhood trauma for each subtype, respectively. The CTQ has demonstrated test–retest reliabilities ranging from 0.79 to 0.86 over an average of four months, as well as internal consistency reliability coefficients ranging from a median of 0.66 to 0.92 across samples [23]. Furthermore, Scher et al. [25] explored the factor structure and reliability of the CTQ in a racially mixed community sample of men and women, and the results have shown an acceptable internal consistency for the entire measure.

World Health Organization Quality of Life

Subjective perceived health-related quality of life is assessed using the Chinese version of the WHOQOL Brief Version Questionnaire [26]. This 28-item questionnaire has been shown to be culturally relevant, with good reliability. Five subscores are obtained from this instrument, measuring overall (2 items), physical (7 items), psychological (6 items), social relations (4 items), and environmental quality of life (9 items). The internal consistency of the questionnaire, as measured by Cronbach's α, is satisfactory (0.82). The higher the score, the better the quality of life.

Statistical analysis

We used t-test to test the differences between the groups for demographic and clinical characteristics. Given the nature of PSQI scale, only a few points in each subscale, and the difference in each step, may not be linear. We used a series of ordinal logistic regression analysis to test the interaction of childhood trauma, and each domain of PSQI among BD-I and BD-II, respectively. For significant interactions, the interaction between PSQI and subdomains of CTQ was done. A supplemental sensitivity analysis with nonparametric correlation test with Spearman's ρ, was also done.

The data were analyzed using the Statistical Package for the Social Science software version 20 for Windows (SPSS Inc., Chicago, Illinois, USA). The differences between the groups were considered significant if p-values were smaller than 0.05.

  Results Top

[Table 1] shows the demographic and clinical characteristics of study participants. [Table 2] shows the characteristics of prescribing sedative medications before sleep.
Table 1: The demographic data, measurement of support function, sleep quality, childhood trauma, daily stress, and quality of life between patients with bipolar disorder-I and those with bipolar disorder-II

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Table 2: The prescription of sedative medications before sleep between bipolar disorder-I and bipolar disorder-II

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As the sleep quality differs among BD-I and BD-II in our sample, a stratified analysis was conducted. [Table 3] is the estimate of ordinal logistic model.
Table 3: The interaction of childhood trauma and social support on components of Pittsburgh Sleep Quality Index

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Further analysis on the subscale of CTQ in BD-II showed a significant interaction on one domain – physical abuse (b = −0.008, Wald χ2 (1) = 5.024, p < 0.05). This effect remained robust (b = −0.012, Wald χ2 (1) = 8.150, p < 0.01) after controlling the use of drug (sedative, BZD, antipsychotic, and antidepressant). As shown in [Figure 1], physical abuse was found to be significantly related to daytime dysfunction among those who had poor social support (b = 0.282, Wald χ2 (1) = 4.81, p < 0.05; ρ = 0.55, p < 0.05), but not among those who had better social support. In summary, physical abuse may be a risk for daytime dysfunction, and may be buffered through social support in BD-II patients.
Figure 1: The association between sleep-related daytime dysfunction and physical abuse among BD-II patients with poor and better social support. The physical abuse was significantly (p < 0.05) related to daytime dysfunction among those with poor social support, but not better social support. PSQI, Pittsburgh Sleep Quality Index; CTQ, Childhood Trauma Questionnaire

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To understand the consequences of daytime dysfunction among BD-II, we did a supplemental correlational analysis. Daytime dysfunction was found to be related to WHOQOL overall (ρ = −0.56, p = 0.001), physical health (ρ = −0.50, p < 0.01), psychological (ρ = −0.59, p < 0.001), social relationship (ρ = −0.68, p < 0.001), and environmental domains (ρ = −0.65, p < 0.001).

  Discussion Top

The study participants of the present study were relatively stable and euthymic, except for a low level of depression in some patients. This is characteristic of typical patients followed up at outpatient clinics [27]. As shown in [Table 1] and [Table 2], the severity of mood as well as prescribing pattern of sedative medications before sleep between BD-I and BD-II were similar. But patients with BD-II in this study [Table 1] had significantly poorer sleep quality than that in patients with BD-I (p < 0.01) as well as significantly poorer life quality (p < 0.05). All findings are compatible with those in other studies [28]. Our study [Table 3] showed that childhood trauma was significantly related to poor sleep quality (p < 0.05), sleep latency (p < 0.01), and daytime dysfunction (p < 0.05) among BD-II patients. These findings are similar to those of a previous large sample study [6]. But that large sample study did not compare the differences between patients with BD-I and BD-II. The difference between the two groups might be related to the genetic validity for sleep trait [29] and dopamine D3 receptor gene [30].

Moreover, the results confirmed that social support provided a significantly more buffer effect for sleep quality in BD-II patients with childhood trauma (p < 0.05), as shown in [Figure 1]. Among these patients, childhood abuse is a significant predictor of poor sleep, and can be significantly buffered by social support which may reduce the daytime dysfunction, as measured by a subscale of PSQI. The analysis [Table 1] also indicated that physical abuse was the most significantly important domain (p < 0.05) in this model. Moreover, this critical interaction was independent of the effect of stress * social support. Our finding implies that childhood trauma is related to poor sleep among BD-II, but not BD-I. Additionally, our supplemental analysis has indicated that the sleep-related daytime dysfunction is related to domains of quality of life among BD-II [31]. Managing daytime dysfunction might be an emerging issue for patients with BD-II.

Residual depression has been reported to be related to poor sleep in BD [32], and residual depression is more prevalent in BD-II rather than BD-I in a clinical observation [17]. Therefore, we speculate that the sleep quality would be more vulnerable in BD-II rather than BD-I. But childhood trauma may be an unidentified cause which is related to sleep disturbance. Specific psychological treatments for childhood trauma can be considered to increase sleep quality [33]. The altered HPA axis in those exposed to childhood trauma may be related to epigenetic changes of stress regulatory genes, such as the glucocorticoid receptor gene, also called the NR3C1 gene, or the FKBP5 gene [34]. The BD patients with childhood trauma may therefore be more vulnerable to life stressors from early life challenges or other epigenetic interactions, which may be linked with more residual symptoms, poor disease outcome, and quality of life [35],[36].

Study limitations

Our findings imply that enhancing the social function may serve as a buffer against poor sleep quality due to previous childhood trauma. The readers should be cautioned against over-interpreting the result because of the following four limitations in this study.

  • The study is cross-sectional in design, with subjective recall of childhood trauma. Thus, the causal relationships cannot be inferred in this study.
  • The personality disorder and alcohol use disorder are common comorbidities in patients with BD, and also could be confounding factors for social support and sleep quality. Due to the original research design, we did not exclude those two comorbidities.
  • Due to small sample size, the statistical power for the parameters in the statistical model is limited, in our controlling the use of drug in the pivotal interaction [Figure 1]. Other stratified test was not controlled. Furthermore, we did not do the correction for multiple comparison.
  • The sleep quality was measured with a subjective questionnaire. Whether the finding is related to objective measures such as polysomnography or actigraphy, remains unclear.


Our findings provided preliminary evidence in favor of the view that childhood trauma may be an important precursor for sleep quality in BD. Future studies are needed to understand the nature of this phenomenon.

  Acknowledgments Top

The authors thank Chien Ting Lin for their administrative support.

  Financial Support and Sponsorship Top

This work was supported by grants from the Ministry of Science and Technology, Taiwan (MOST 107-2314-B-006-082 and MOST 108-2314-B-006-045), and the National Cheng Kung University Hospital (NCKUH-10903014 and NCKUH-11005007).

[TAG:2]Conflicts of Interest[/TAG:2]

The authors declare that they have no conflicts of interest in relation to this work. The funders had no rôle in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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  [Figure 1]

  [Table 1], [Table 2], [Table 3]


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