Circadian, Reward, and Emotion Systems in Teens prospective longitudinal study: protocol overview of an integrative reward-circadian rhythm model of first onset of bipolar spectrum disorder in adolescence.

BACKGROUND: Bipolar spectrum disorders (BSDs) are associated with a heightened sensitivity to rewards and elevated reward-related brain function in cortico-striatal circuitry. A separate literature documents social and circadian rhythm disruption in BSDs. Recently, integrated reward-circadian models of BSDs have been proposed. These models draw on work indicating that the two systems influence each other and interact to affect mood functioning. When dysregulated, reward and circadian system signaling may combine to form a positive feedback loop, whereby dysregulation in one system exacerbates dysregulation in the other. Project CREST (Circadian, Reward, and Emotion Systems in Teens) provides a first systematic test of reward-circadian dysregulation as a synergistic and dynamic vulnerability for first onset of BSD and increases in bipolar symptoms during adolescence. METHODS: This NIMH-funded R01 study is a 3-year prospective, longitudinal investigation of approximately 320 community adolescents from the broader Philadelphia area, United States of America. Eligible participants must be 13-16 years old, fluent in English, and without a prior BSD or hypomanic episode. They are being selected along the entire dimension of self-reported reward responsiveness, with oversampling at the high tail of the dimension in order to increase the likelihood of BSD onsets. At Times 1-6, every 6 months, participants will complete assessments of reward-relevant and social rhythm disruption life events and self-report and diagnostic assessments of bipolar symptoms and episodes. Yearly, at Times 1, 3, and 5, participants also will complete self-report measures of circadian chronotype (morningness-eveningness) and social rhythm regularity, a salivary dim light melatonin onset (DLMO) procedure to assess circadian phase, self-report, behavioral, and neural (fMRI) assessments of monetary and social reward responsiveness, and a 7-day ecological momentary assessment (EMA) period. During each EMA period, participants will complete continuous measures of sleep/wake and activity (actigraphy), a daily sleep diary, and three within-day (morning, afternoon, evening) measures of life events coded for reward-relevance and social rhythm disruption, monetary and social reward responsiveness, positive and negative affect, and hypo/manic and depressive symptoms. The fMRI scan will occur on the day before and the DLMO procedure will occur on the first evening of the 7-day EMA period. DISCUSSION: This study is an innovative integration of research on multi-organ systems involved in reward and circadian signaling in understanding first onset of BSD in adolescence. It has the potential to facilitate novel pharmacological, neural, and behavioral interventions to treat, and ideally prevent, bipolar conditions.

The relationship between physical activity states and depressive symptoms: Using ambulatory assessment to characterize day-to-day associations among individuals with and without bipolar spectrum disorder.

INTRODUCTION: The role of activation in the pathogenesis of bipolar spectrum disorders (BSD) is of growing interest. Physical activity is known to improve mood, but it is unclear whether low activity levels contribute to inter-episode depressive symptoms observed in BSD. This study examined whether sedentary and vigorous activity, as well as the timing of the activity, were differentially associated with next-day depressive symptoms for individuals at low risk for BSD, high-risk for BSD, and diagnosed with BSD. METHODS: Young adults (n = 111, ages 18-27) from three groups (low BSD risk, high BSD risk, and BSD diagnosis), participated in a 20-day ecological momentary assessment study. Physical activity was measured via wrist actigraphy counts. The percentage of time awake spent in sedentary, light, moderate, and vigorous activity states was calculated, as was the percentage of morning hours and evening hours in each activity state. Multilevel models examined whether the BSD risk group moderated associations between sedentary and vigorous activity and depressive symptoms, which were assessed three times daily. RESULTS: There were no between-group differences in time spent in each activity state, nor were there main effects of sedentary or vigorous activity on depression. Increased time spent engaging in vigorous activity was associated with a greater reduction in subsequent depressive symptoms for the BSD group. An increase in the evening, but not morning, vigorous activity was significantly associated with a reduction in subsequent depressive symptoms for the BSD group after controlling for chronotype. CONCLUSIONS: Interventions targeting physical activity may effectively help regulate inter-episode mood disturbances in BSD.

The path from mood symptoms to substance use: A longitudinal examination in individuals with and at risk for bipolar spectrum disorders.

BACKGROUND: Adolescent substance use poses a critical public health challenge, intertwined with risk-taking behavior, criminality, functional impairment, and comorbid mental and physical health issues. Adolescents with bipolar spectrum disorders (BSD) exhibit heightened susceptibility to substance use, necessitating a nuanced exploration of the bipolar-substance use relationship. METHODS: This study addressed gaps in the literature by employing a prospective, longitudinal design with 443 Philadelphia-area adolescents, tracking BSD symptoms and substance use. We predicted that BSD symptoms would be associated with increases in substance use, and that these effects would be more pronounced for individuals with a BSD and those with high reward sensitivity. RESULTS: Hypomanic symptoms predicted subsequent substance use, with a stronger association observed in individuals diagnosed with BSD. Contrary to expectations, depressive symptoms did not exhibit a similar relationship. Although the hypothesized moderating role of reward sensitivity was not supported, higher reward sensitivity predicted increased substance use. LIMITATIONS: Symptoms and substance use are only captured for the month prior to each session due to the assessment timeline. This highlights the benefits of frequent assessments over a shorter time frame to monitor real-time changes. Alternative classification methods for reward sensitivity, such as brain or behavior-based assessments, might yield different results. CONCLUSIONS: This study's contributions include evaluating substance use broadly, utilizing a longitudinal design for temporal clarity, and shifting the focus from substance use predicting mood symptoms to the inverse. The findings underscore the need for continued exploration of mood symptom predictors of substance use, emphasizing the role of reward sensitivity.

Social and circadian rhythm dysregulation and suicide: A systematic review and meta-analysis.

This systematic review of 52 studies provides a quantitative synthesis of the empirical literature on social and circadian rhythm correlates of suicidal thoughts and behaviors (STB). Small-to-medium pooled effect sizes were observed for associations between evening chronotype and STB and suicidal ideation (SI), although the pooled effect size diminished when accounting for publication bias. Three studies employed longitudinal designs and suggested eveningness was predictive of future STB, with a small-to-medium effect size. Social rhythm irregularity was also a significant correlate of STB with pooled effect sizes in the medium range. Overall circadian rhythm disruption was not associated with STB, although certain circadian rhythm metrics, including mean daytime activity, circadian rhythm sleep-wake disorder diagnosis, and actigraphy-assessed amplitude were associated with STB. Pooled effect sizes for these indices were in the medium to large range. There is a need for additional longitudinal research on actigraphy-based circadian parameters and objective markers of circadian phase (i.e., dim-light melatonin onset) to gain a clearer understanding of associations of endogenous circadian function and STB beyond that which can be captured via self-report.

Social jetlag and trajectories of mood symptoms and reward responsiveness in individuals at low-risk, high-risk, and with bipolar spectrum disorders: An ecological momentary assessment study.

A specific type of sleep disruption, social jetlag, involves an incongruence of sleep time between weekends and weekdays. This study investigated relationships between social jetlag and mood symptom lability and trajectories of daily reward responsiveness and mood symptoms. Participants (N = 130) from three groups (moderate reward sensitivity, high reward sensitivity, and high reward sensitivity with a diagnosed bipolar spectrum disorder [BSD]) were recruited from an ongoing longitudinal study based on their self-reported reward sensitivity and a diagnostic interview. For this study, they completed 20 days of ecological momentary assessment (EMA) of reward responsiveness and mood symptoms and a daily sleep diary. Social jetlag was significantly associated with differences in trajectories of depressive symptoms between groups. Specifically, greater social jetlag was associated with a greater increase in depressive symptoms over the 20 days for participants in the high reward sensitivity and BSD groups compared to the moderate reward sensitivity group. Social jetlag also was significantly associated with depressive symptom lability during the EMA period, but this finding was reduced to a trend toward significance when controlling for self-reported sleep duration. The study adds to the literature with methodological strengths including the EMA design and assessment of symptom and reward responsiveness trajectories.

An examination of bidirectional associations between physical activity and mood symptoms among individuals diagnosed and at risk for bipolar spectrum disorders.

OBJECTIVES: Activation, a construct including energy and activity, is a central feature of Bipolar Spectrum Disorders (BSDs). Prior research found motor activity is associated with affect, and this relationship may be stronger for individuals with BSDs. The aims of this study were to investigate bidirectional relationships between physical activity and mood and evaluate whether bipolar risk status moderated potential associations. METHODS: Young adults at low-risk, high-risk, and diagnosed with BSD participated in a 20-day EMA study in which they wore an actiwatch to measure physical activity and sleep/wake cycles. They also reported depressive and hypo/manic symptoms three times daily. Multilevel linear models were estimated to examine how bipolar risk group moderated bidirectional relationships between physical activity and mood symptoms at within-day and between-day timescales. RESULTS: Physical activity was significantly associated with subsequent mood symptoms at the within-day level. The relationship between physical activity and depressive symptoms was moderated by BSD risk group. An increase in physical activity resulted in a greater reduction of depressive symptoms for the BSD group compared to the low-risk and high-risk groups. CONCLUSIONS: Interventions targeting activity like behavioral activation may improve residual inter-episode mood symptoms.