Diso ep rde le rs S f & o T l h a e n r r a u p Kanady et al., J Sleep Disord Ther 2015, 4:2 o y Journal of Sleep Disorders & Therapy J DOI: 10.4172/2167-0277.1000193 ISSN: 2167-0277 Research Article Open Access A Retrospective Examination of Sleep Disturbance across the Course of Bipolar Disorder Jennifer C Kanady1, Adriane M Soehnera2 and Allison G Harvey1* 1Department of Psychology, University of California, Berkeley, Berkeley, CA, USA 2Department of Psychiatry, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA *Corresponding author: Allison G. Harvey, Ph.D., 3210 Tolman Hall #1650, Berkeley, CA, 94720-1650, USA, Tel: 510-642-7138; E-mail: [email protected] Received date: Feb 02, 2015, Accepted date: Mar 24, 2015, Published date: Mar 30, 2015 Copyright: © 2015 Kanady JC, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Background: Sleep disturbance is a prevalent and clinically significant feature of bipolar disorder. However, there are aspects of sleep and bipolar disorder that have been minimally characterized. This study aims to fill several gaps in the literature by examining the prevalence, coexistence, and persistence of sleep disturbance retrospectively across a five-year period in bipolar disorder. Methods: Fifty-one people with bipolar disorder I and comorbid insomnia who were currently inter-episode completed the NIMH Retrospective Life-Charting Methodology (the life chart). The life chart was used to document the prevalence, coexistence, and persistence of insomnia, hypersomnia, delayed sleep phase, reduced sleep need, and irregular sleep patterns across the course of five years. Results: Across the five year period, manic months were primarily characterized by reduced sleep need (62.8%) and insomnia (38.1%), depressive months by hypersomnia (56.0%) and insomnia (51.9%), mixed months by all five types of sleep disturbance, and inter-episode months by insomnia (67.4%). There was coexistence in the types of sleep disturbance experienced. Further, each type of sleep disturbance demonstrated persistence across the five years, with persistence rates being the highest for insomnia (49.0–58.8%). Conclusions: Sleep disturbance is a prevalent and complex feature across mood episodes and inter-episode periods of bipolar disorder. Further, there is variation in the types of sleep disturbance experienced. Keywords Bipolar disorder; Sleep disturbance; Prevalence; during inter-episode states [10]. Different types of sleep disturbance Coexistence; Persistence characterize bipolar disorder. Insomnia, for example, is highly prevalent [11] with as many as 100% of people with bipolar disorder Introduction report experiencing insomnia while depressed [12] and 55% reporting insomnia during the inter-episode period [10]. Episodes of depression Bipolar disorder is a severe disorder characterized by mood are also characterized by hypersomnia [13] and 25% of people endorse episodes; namely, periods of elevated or irritable mood, referred to as symptoms of hypersomnia during the inter-episode period [14]. A mania, periods of depression, and mixed manic and depressed states reduced need for sleep is often exhibited during mania [15] and mixed [1]. Bipolar disorder is further characterized by periods identified as episodes are characterized by decreases in total sleep time [16]. neither depressive nor manic, a phase referred to as the inter-episode Furthermore, people with bipolar disorder are more likely to report period [2-4]. Although there have been important advances in circadian dysfunction, such as a delayed sleep phase preference, when psychological and pharmacological treatments for bipolar disorder, it compared to healthy individuals, [17,18] and irregular sleep patterns remains a severe and chronic psychiatric illness with a lifetime are commonly reported [19-21]. prevalence of approximately 1.0% [5] and is one of the 10 most disabling conditions worldwide [6]. Further, bipolar disorder is Notably, these different types of sleep disturbance can coexist and associated with significant impairment across numerous functional sleep disturbance is often persistent. For example, two studies have and health domains and this impairment often persists during the examined the coexistence of sleep disturbance in the context of inter-episode period [2,3,7-9]. Sleep is one important domain that is depression and found that 10% of children with Major Depressive often impaired in bipolar disorder and is the focus of the current Disorder [22,23] and 8-11% of older adults in a depressive episode [23] study. experience insomnia and hypersomnia simultaneously. Moreover, in general population studies, 6% of adults [24] and 8% of young adults Sleep disturbance is a common feature of bipolar disorder. Within [25] also reported comorbid insomnia and hypersomnia. The the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), coexistence of other types of sleep disturbance has yet to be examined. sleep disturbance is listed as a diagnostic criterion of mania, Sleep disturbance is also persistent. Longitudinal studies in healthy, depression, and mixed episodes [1]. Moreover, sleep disturbance aging, and depressed samples have shown insomnia persistence rates persists during the inter-episode period and as many as 70% of people ranging from 40-74% [25-29]. Insomnia relapse rates are high and 25% with bipolar disorder report clinically significant sleep disturbance of individuals who remit report at least one relapse over a 3-year J Sleep Disord Ther Volume 4 • Issue 2 • 1000193 ISSN:2167-0277 JSDT, An open access Citation: Kanady JC, Soehnera AM, Harvey AG (2015) A Retrospective Examination of Sleep Disturbance across the Course of Bipolar Disorder. J Sleep Disord Ther 4: 193. doi:10.4172/2167-0277.1000193 Page 2 of 10 period [30]. Furthermore, individuals with symptoms of insomnia, 39]. Ethnicity and race of the participants reflected the diversity of who do not meet diagnostic criteria for insomnia, are more likely to Alameda County (63% Caucasian, 11.1% African American, 9.3% relapse and report worsening of insomnia over time [30]. Few studies Asian, 9.3% more than one ethnicity, 3.7% declined to answer, 1.9% have examined the persistence of other types of sleep disturbance. American Indian/Alaska Native, 1.9% other). Participants were inter- However, one study found that the lifetime prevalence of hypersomnia episode (i.e., not currently manic or depressed) at the time of the alone is 8.2% and the lifetime prevalence of hypersomnia in assessment. An inter-episode period was defined by a score of 24 or conjunction with insomnia is 8% [25]. less on the Inventory of Depressive Symptomatology, Clinician Rating [IDS-C; 40] and a score of 12 or less on the Young Mania Rating Scale, Taken together, it is clear that sleep disturbance is a prevalent and [YMRS; 41] which are standard measures and cutoffs in the bipolar variable feature of bipolar disorder and sleep disturbance may coexist literature. Participants were required to be on a stable medication and be persistent. However, a number of unanswered questions regimen for at least four weeks prior to enrollment in the study and remain. For instance, no studies have examined the course or under the care of a treating physician or nurse practitioner who variability of sleep disturbance across several mood episodes and inter- manages their bipolar disorder. All participants were at least 18 years episode periods of bipolar disorder. Previous studies examining sleep old and reported English fluency, which was necessary as all aspects of disturbance in bipolar disorder have typically focused on a single the protocol were in English. mood episode or a single period of time. Moreover, previous research has typically focused on just one type of disturbance and therefore, the Participants also met criteria for current insomnia. Insomnia was potential coexistence of different types of sleep disturbance during a defined as a subjective report of difficulty falling asleep (>30 minutes), single period of time has yet to be determined. A second gap is that the difficulty maintaining sleep (wake after sleep onset >30 minutes), persistence of sleep disturbance across the course of bipolar disorder and/or waking up too early (early morning awakening >30 minutes), has yet to be established. Sleep disturbance is a common feature of with associated daytime complaints, at least three times a week for at both mood episodes and the inter-episode period. However, it is least one month. Further, these sleep difficulties had to occur despite unclear if, and how, sleep disturbance endures or changes from year to adequate opportunity to sleep. These criteria reflect a combination of year. Research Diagnostic Criteria, [42] International Classification of Sleep Disorders [ICSD-2; 43] and DSM-IV-TR standards [15]. The Duke The goal of the present study was to contribute to the process of Structured Interview for Sleep Disorders [DSISD; 44], a valid and closing these important gaps in the literature by examining the course reliable semi-structured interview, was used to establish all insomnia of sleep disturbance across bipolar disorder. The first aim was to diagnoses. retrospectively examine the prevalence and coexistence of insomnia, hypersomnia, delayed sleep phase, reduced sleep need, and irregular