Are Owls and Larks Different When it Comes to Aggression? Genetics, Neurobiology, and Behavior

Sleep quality mediates the association between chronotype and mental health in young Indian adults

There is increasing recognition of 'higher preference for eveningness' as a potential independent risk factor for poor mental health. To examine the chronotype-mental health relationship while also quantifying the potential roles of poor sleep quality, relevant personality traits, and childhood trauma, we assessed 282 young adults (18-40 years; 195 females) residing in North India, between January and March 2023 (to control for seasonal variation), using self-report measures of diurnal preference, sleep patterns, mental health (depression, anxiety, and stress), personality traits (extraversion, neuroticism, schizotypy, and impulsivity), and childhood trauma. The results showed a significant association between eveningness and poor mental health but this association was fully mediated by poor sleep quality. Neuroticism, emotional abuse and cognitive disorganisation were correlated with eveningness as well as with poor mental health and sleep quality. Neuroticism and emotional abuse, but not cognitive disorganisation, also had indirect effects on mental health via sleep quality. Our findings highlight the crucial role played by sleep quality in the chronotype-mental health relationship.

Sex differences in the relationship between morningness-eveningness components, mood and well-being among Bangladeshi university students

On the Morningness/Eveningness (M/E) continuum, eveningness has been related to mood disorder and poor well-being. M/E differs between men and women throughout their lifespan. However, there is a lack of information on sex differences in the relationship between M/E, mood, and well-being. This study aimed to test sex differences in the M/E, mood, and well-being relationship with consideration of two components of M/E, morning affect, and morning preference. A sample of 981 Bangladeshi university students (607 men) aged 18 to 27 (M = 21.95) completed Bangla versions of the Composite Scale of Morningness (CSM), BRUnel Mood Scale (BRUMS), and Positive Mental Health scale (PMH-scale) through an online survey. Multiple regression analyses were used to test the relationship of M/E components with mood and well-being. The results showed that the relationship between M/E, mood, and well-being was greater in women than in men. A lower score on both M/E components was related to higher negative moods (anger, confusion, depression, fatigue, and tension) and poor well-being. In regression analysis, only morning affect was found to be significant, which means that morning affect mainly contributes to the relation between M/E, mood, and well-being. Finally, sex by morning affect interaction indicated that the relation was higher for women. Therefore, higher eveningness could be more hazardous for women than men. Greater insight into the independent contribution of morning affect may facilitate understanding of the chronotype effects on psychological outcomes in men and women.

Assessment of subjective sleep quality and issues in aggression: Intermittent Explosive Disorder compared with psychiatric and healthy controls

BACKGROUND

While prior research has linked clinical sleep issues and aggression, little is known about how clinical sleep issues among individuals with Intermittent Explosive Disorder (IED), which is characterized by a pervasive pattern of impulsive aggression and associated with consequences across multiple life-domains. The present study aims to examine clinical sleep issues among individuals with IED in contrast to individuals with other psychopathology and healthy controls.

METHODS

257 adults, including 100 healthy controls, 85 psychiatric controls and 72 individuals with IED, took part in this study. Participants completed the Structured Clinical Interview for DSM-V Diagnoses, Assessment of clinical sleep issues included the Pittsburgh Sleep Quality Inventory (PSQI), obstructive sleep apnea (OSA) screening, and the Epworth Sleepiness Scale (ESS) as well as assessments of aggression and impulsivity.

RESULTS

IED study participants reported significantly worse sleep quality, increased sleep latency, greater daytime sleepiness and symptoms of OSA. Daytime sleepiness and sleep quality was correlated with impulsivity and aggression.

CONCLUSIONS

This study suggests that individuals with IED have clinically relevant sleep anomalies, and that these are directly associated with measures of impulsivity and aggression. Clinicians treating aggressive individuals are advised to assess and treat such individuals for sleep issues.

Owls and larks do not exist: COVID-19 quarantine sleep habits

Background

The coronavirus pandemic presented a unique opportunity to study the daily temporal patterns and sleep habits of humans. The question to be explored was: Are there discernible differences in sleep between the normal operational environment and the stay-at-home condition?

Methods

This international prospective study analyzed results from the sleep-wake patterns questionnaire, daily logs, and interviews. Surveys were administered to the healthy volunteers (age 15–60 y) with stay-at-home for a month or more, without previous sleep disorders and mood-related complaints; volunteers were not involved in online education/work daily timetable-related activities.

Results

We analyzed 3787 subjects with average stay-at-home of 65 ± 9 days. The most significant changes in sleep occurred during the first ten days when the difference between weekdays and weekends disappeared and changes occurred in napping habits. The majority of the participants (66.8%) shifted toward eveningness when the self-selected sleep was possible and 1869 volunteers appeared to be owls (49.4%), 823 (21.7%) exercised “typical” sleep, 478 (12.6%) were larks, and 617 (16.3%) participants were completely desynchronized to the end of stay-at-home. In addition, 497 participants (13.1%) alternated their sleep habits. The most of the desynchronized participants (n = 414) were older than 50 years (age correlation r = 0.80), and predominantly males (n = 297, r = 0.76).

Conclusion

In self-selected sleep conditions, the timing of sleep and sleep habits significantly differ from those of socially and economically fixed daily routine conditions. The changes in daily temporal patterns of humans during a prolonged stay-at-home situation indicate that human sleep habits may change according to existing living conditions.

Potential Pathways for Circadian Dysfunction and Sundowning-Related Behavioral Aggression in Alzheimer's Disease and Related Dementias

Patients with Alzheimer's disease (AD) and related dementias are commonly reported to exhibit aggressive behavior and other emotional behavioral disturbances, which create a tremendous caretaker burden. There has been an abundance of work highlighting the importance of circadian function on mood and emotional behavioral regulation, and recent evidence demonstrates that a specific hypothalamic pathway links the circadian system to neurons that modulate aggressive behavior, regulating the propensity for aggression across the day. Such shared circuitry may have important ramifications for clarifying the complex interactions underlying "sundowning syndrome," a poorly understood (and even controversial) clinical phenomenon in AD and dementia patients that is characterized by agitation, aggression, and delirium during the late afternoon and early evening hours. The goal of this review is to highlight the potential output and input pathways of the circadian system that may underlie circadian dysfunction and behavioral aggression associated with sundowning syndrome, and to discuss possible ways these pathways might inform specific interventions for treatment. Moreover, the apparent bidirectional relationship between chronic disruptions of circadian and sleep-wake regulation and the pathology and symptoms of AD suggest that understanding the role of these circuits in such neurobehavioral pathologies could lead to better diagnostic or even preventive measures.

Time of Day Matters: An Exploratory Assessment of Chronotype in a Forensic Psychiatric Hospital

A growing body of evidence links the late chronotype to mental illness, aggression, and aversive personality traits. However, much of what we know about these associations is based on healthy cohorts, and it is unclear how individuals with high levels of aggression, including forensic psychiatric populations, but not offenders, are affected. The present study aimed to measure chronotype in a forensic psychiatric inpatient population, evaluate the impact of diagnosis, and identify any interactive relationships between chronotype, diagnosis, aggression, and dark triad traits. Subjects completed the reduced Morningness-Eveningness Questionnaire (rMEQ), Munich ChronoType Questionnaire (MCTQ), Pittsburgh Sleep Quality Index (PSQI), Buss Perry Aggression Questionnaire-Short Form (BPAQ-SF), and Short Dark Triad Questionnaire (SD3). We sampled 55 forensic psychiatric patients (52 males) between the ages of 23 and 73 years (mean ± SD: 39.6 ± 14.3 years). Among the patients sampled, 25% were evening types and 36% were morning types. Eveningness was greater in patients with a personality disorder; however, no chronotype differences were found for psychosis patients. Patients without psychosis had a positive association between anger and eveningness, as well as between hostility and eveningness. For subjects with a substance use disorder, morningness was positively associated with narcissism. Conversely, an association between eveningness and greater narcissism was identified in patients who did not have a substance use disorder. These findings suggest that, compared to the general population, evening types are more prevalent in forensic psychiatric populations, with the strongest preference among patients diagnosed with a personality disorder. No differences in chronotype were identified for psychosis patients, which may be related to anti-psychotic medication dosing. Given the sex distribution of the sample, these findings may be more relevant to male populations.