Affective Bias, Chronophysiology, and Depression: Toward a Synthesis.

Depression is associated with disruptions in affective processing and chronophysiology. However, the relationships between affective processing and chronophysiology are not well-described. This dissertation addresses critical gaps in the literature on affective bias in depression, the effects of circadian rhythms and sleep on affective processing, and organization of brain activity during sleep in depression. First, anticipation for future affective events was examined in individuals with dysthymia (DYS) and controls. Warning stimuli forecasted the affective valence of subsequently presented adjectives, and participants indicated whether each adjective would describe them over the next two weeks. Controls expected fewer negative, and individuals with DYS expected fewer positive, adjectives to apply to them in the future. Event-related potentials (ERP) indicated increased physiological anticipation in controls prior to positive versus other adjectives. In sum, controls and individuals with DYS exhibit different behavioral and neurophysiological biases in anticipation for future affective events. Second, the impact of time of day and sex on incentive-based decision making was assessed in controls. Participants completed the Iowa Gambling Task (IGT) either in the morning (08:00- 10:00) or evening (20:00- 22:00). Males had better IGT performance in the morning than evening. Furthermore, pre-session sleep duration was positively correlated with morning IGT performance in females, but not males. Overall sex differences in IGT performance were not observed. In sum, chronophysiology predicts decision making, but does so differently for females and males. Third, rhythms in bursts of beta- and delta-frequency activity during sleep were characterized in individuals with major depressive disorder (MDD) and controls. Period amplitude analysis (PAA) quantified the percent time in beta- and delta-frequency activity across a night of sleep, and power spectral analyses (PSA) applied to PAA results quantified the rhythmicity of activity bursts. Participant sex, rather than diagnosis, predicted PSA results. In sum, bursts in beta- and delta-frequency activity during sleep are less predictably organized in females than males. Together, these studies provide a foundation for integrative research on affective processing, chronophysiology, and depression. They also indicate that sex differences in sleep and circadian rhythms are important to consider when evaluating decision making skill and organization of brain activity.Ph.D.PsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/77900/1/mcasemen_1.pd

Conditional risk for PTSD among Latinos: A systematic review of racial/ethnic differences and sociocultural explanations

Conditional risk for Posttraumatic Stress Disorder (PTSD)—defined as prevalence, onset, persistence, or severity of PTSD after traumatic exposure—appears to be higher among Latinos relative to non-Latinos after accounting for sociodemographic factors. This systematic review focuses on differences in conditional risk for PTSD between Latinos and non-Latinos (White, Black, or combined) and across Latino subgroups in studies that adjust for trauma exposure. We discuss methodological characteristics of existing articles and sociocultural explanatory factors. Electronic bibliographic searches were conducted for English-language articles published in peer-reviewed journals between 1991 and 2012. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Twenty-eight articles met inclusion criteria. Consistent support was found for elevated rates of PTSD onset and PTSD severity among Latinos relative to non-Latino Whites. The evidence on racial/ethnic differences in conditional risk for PTSD prevalence and PTSD persistence is mixed. Twenty-four articles evaluated sociocultural explanations, with the strongest support found for racial/ethnic variation in peri-traumatic responses and structure of PTSD. There were also consistent main effects for social disadvantage in studies that simultaneously adjusted for effects of race/ethnicity. Future research should use theoretically-driven models to formally test for interactions between sociocultural factors, race/ethnicity, and PTSD probability

Sleep‐disordered breathing in major depressive disorder

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99077/1/jsr12029.pd

The time course of off-line motor sequence learning

The acquisition of motor skill occurs with practice, but skill can also increase between sessions, a process termed “off-line learning”. Here, we investigated the amount of time required for the off-line development of skills. Participants were tested on an implicit version of the Serial Reaction Time Task and re-tested 1, 4 or 12 h later. Only those re-tested 4 h or 12 h after initial testing showed off-line improvements. This demonstrates that implicitly acquired skills can increase between sessions and the process occurs over hours

Digital Cognitive Behavioral Therapy for Insomnia Promotes Later Health Resilience During the Coronavirus Disease 19 (COVID-19) Pandemic

STUDY OBJECTIVES: Stressful life events contribute to insomnia, psychosocial functioning, and illness. Though individuals with a history of insomnia may be especially vulnerable during stressful life events, risk may be mitigated by prior intervention. This study evaluated the effect of prior digital cognitive-behavioral therapy for insomnia (dCBT-I) versus sleep education on health resilience during the COVID-19 pandemic. METHODS: COVID impact, insomnia, general- and COVID-related stress, depression, and global health were assessed in April 2020 in adults with a history of insomnia who completed a randomized controlled trial of dCBT-I (n = 102) versus sleep education control (n = 106) in 2016-2017. Regression analyses were used to evaluate the effect of intervention conditions on subsequent stress and health during the pandemic. RESULTS: Insomnia symptoms were significantly associated with COVID-19 related disruptions, and those previously received dCBT-I reported less insomnia symptoms, less general stress and COVID-related cognitive intrusions, less depression, and better global health than those who received sleep education. Moreover, the odds for resurgent insomnia was 51% lower in the dCBT-I versus control condition. Similarly, odds of moderate to severe depression during COVID-19 was 57% lower in the dCBT-I condition. CONCLUSIONS: Those who received dCBT-I had increased health resilience during the COVID-19 pandemic in adults with a history of insomnia and ongoing mild to moderate mental health symptoms. These data provide evidence that dCBT-I is a powerful tool to promote mental and physical health during stressors, including the COVID-19 pandemic

Self-efficacy in Insomnia Symptom Management after Digital CBT-I Mediates Insomnia Severity during the COVID-19 Pandemic

STUDY OBJECTIVES: Digital cognitive behavioral therapy for insomnia (dCBT-I) can reduce acute insomnia and depressive symptoms and prevent symptom recurrence. The current study evaluated self-efficacy in managing insomnia symptoms as a potential mediator of the relationship between prior dCBT-I and subsequent insomnia and depressive symptoms assessed during the coronavirus 2019 (COVID-19) pandemic. METHOD: Participants were 208 adults who completed a randomized controlled trial of dCBT-I versus sleep education in 2016-2017 and also completed self-report assessments of insomnia, depression, and self-efficacy in managing insomnia symptoms. Data were collected in May 2020, five weeks into state-wide COVID-19 stay-at-home orders. Regression and mediation analyses were used to evaluate the extent to which self-efficacy accounted for the relationship between treatment condition and improvement in insomnia and depressive symptoms from pre-treatment to COVID-19 follow-up. RESULTS: Prior dCBT-I predicted greater self-efficacy in managing insomnia symptoms. Self-efficacy accounted for 49% and 67% of the protective effect of dCBT-I against COVID-era insomnia and depressive symptoms, respectively. CONCLUSIONS: This study affirms the importance of self-efficacy as a key intervention outcome and potential mechanism by which dCBT-I predicts future sleep and mental health. Future studies that evaluate the role of self-efficacy in treatment effectiveness and resilience can provide additional clues about how to optimize dCBT-I for maximum benefit to public health

Neural Reward Processing Mediates the Relationship between Insomnia Symptoms and Depression in Adolescence

Study objectivesEmerging evidence suggests that insomnia may disrupt reward-related brain function-a potentially important factor in the development of depressive disorder. Adolescence may be a period during which such disruption is especially problematic given the rise in the incidence of insomnia and ongoing development of neural systems that support reward processing. The present study uses longitudinal data to test the hypothesis that disruption of neural reward processing is a mechanism by which insomnia symptoms-including nocturnal insomnia symptoms (NIS) and nonrestorative sleep (NRS)-contribute to depressive symptoms in adolescent girls.MethodParticipants were 123 adolescent girls and their caregivers from an ongoing longitudinal study of precursors to depression across adolescent development. NIS and NRS were assessed annually from ages 9 to 13 years. Girls completed a monetary reward task during a functional MRI scan at age 16 years. Depressive symptoms were assessed at ages 16 and 17 years. Multivariable regression tested the prospective associations between NIS and NRS, neural response during reward anticipation, and the mean number of depressive symptoms (omitting sleep problems).ResultsNRS, but not NIS, during early adolescence was positively associated with late adolescent dorsal medial prefrontal cortex (dmPFC) response to reward anticipation and depressive symptoms. DMPFC response mediated the relationship between early adolescent NRS and late adolescent depressive symptoms.ConclusionsThese results suggest that NRS may contribute to depression by disrupting reward processing via altered activity in a region of prefrontal cortex involved in affective control. The results also support the mechanistic differentiation of NIS and NRS