Associations between diurnal preference, impulsivity and substance use in a young-adult student sample

A multinational analysis of how emotions relate to economic decisions regarding time or risk

Emotions have been theorized to be important drivers of economic choices, such as intertemporal or risky decisions. Our systematic review and meta-analysis of the previous literature (378 results and 50,972 participants) indicates that the empirical basis for these claims is mixed and the cross-cultural generalizability of these claims has yet to be systematically tested. We analysed a dataset with representative samples from 74 countries (n = 77,242), providing a multinational test of theoretical claims that individuals' ongoing emotional states predict their economic preferences regarding time or risk. Overall, more positive self-reported emotions generally predicted a willingness to wait for delayed rewards or to take favourable risks, in line with some existing theories. Contrary to the assumption of a universal relationship between emotions and decision-making, we show that these relationships vary substantially and systematically across countries. Emotions were stronger predictors of economic decisions in more economically developed and individualistic countries.

Exploring the Causal Association between Morning Diurnal Preference and Psychiatric Disorders: A Bidirectional Two-Sample Mendelian Randomization Analysis

BACKGROUND

The causal connection between morning diurnal preference and psychiatric disorders remains enigmatic. Using bidirectional two-sample Mendelian randomization (MR), we aim to explore the potential causal associations between morning diurnal preference and seven prominent psychiatric disorders.

METHODS

MR is a genetic epidemiological method that leverages genetic variants as instrumental variables to infer causal associations between exposures and outcomes. We obtained morning diurnal preference data from genome-wide association study (GWAS) datasets and identified 252,287 individuals as morning people. Psychiatric disorder data were sourced from the FinnGen consortium R9 dataset. Our primary analysis used the inverse-variance weighted (IVW) approach to evaluate the overall causal effect by combining the estimates from each genetic variant. Addition analyses, including weighted median, MR-Egger regression, weighted mode, and simple mode techniques were conducted to ensure robustness.

RESULTS

Being a morning person is related to reduced odds of multiple psychiatric disorders, including depression or dysthymia (OR: 0.93, 95% CI: 0.88, 0.999), anxiety disorders (OR: 0.90, 95% CI: 0.84, 0.96), self-harming behaviors (OR: 0.87, 95% CI: 0.76, 0.99), substance-use disorders (OR: 0.81, 95% CI: 0.71, 0.93), alcohol dependence (OR: 0.82, 95% CI: 0.73, 0.92), alcohol use disorders (OR: 0.85, 95% CI: 0.76, 0.94), acute alcohol intoxication (OR: 0.86, 95% CI: 0.76, 0.96), schizophrenia (OR: 0.77, 95% CI: 0.65, 0.92), and schizophrenia or delusion (OR: 0.80, 95% CI: 0.70, 0.92). Alcohol dependence (OR: 0.97, 95% CI: 0.94, 0.999) and alcohol use disorders (OR: 0.96, 95% CI: 0.94, 0.99) were also related to a lower morning diurnal preference.

CONCLUSIONS

Our study provides evidence that being a morning person is a protective factor for various psychiatric disorders from a genetic perspective. The results provide insights for potential targeted interventions to improve mental wellbeing.

Disrupted Circadian Rhythms and Substance Use Disorders: A Narrative Review

Substance use disorder is a major global health concern, with a high prevalence among adolescents and young adults. The most common substances of abuse include alcohol, marijuana, cocaine, nicotine, and opiates. Evidence suggests that a mismatch between contemporary lifestyle and environmental demands leads to disrupted circadian rhythms that impair optimal physiological and behavioral function, which can increase the vulnerability to develop substance use disorder and related problems. The circadian system plays an important role in regulating the sleep-wake cycle and reward processing, both of which directly affect substance abuse. Distorted substance use can have a reciprocal effect on the circadian system by influencing circadian clock gene expression. Considering the detrimental health consequences and profound societal impact of substance use disorder, it is crucial to comprehend its complex association with circadian rhythms, which can pave the way for the generation of novel chronotherapeutic treatment approaches. In this narrative review, we have explored the potential contributions of disrupted circadian rhythms and sleep on use and relapse of different substances of abuse. The involvement of circadian clock genes with drug reward pathways is discussed, along with the potential research areas that can be explored to minimize disordered substance use by improving circadian hygiene.

Chinese self-report version of biological rhythms interview for assessment in neuropsychiatry (C-BRIAN-SR) - psychometric properties and prospective follow-up in patients with non-seasonal depression

This study examined the psychometric properties and longitudinal changes of the self-reporting Traditional Chinese version of Biological Rhythms Interview for Assessment in Neuropsychiatry (C-BRIAN-SR) among healthy controls (HC) and patients with major depressive episode (MDE). Eighty patients with a current MDE and 80 HC were recruited. Assessments were repeated after two weeks in HC, and upon the discharge of MDE patients to examine the prospective changes upon remission of depression. The C-BRIAN-SR score was significantly higher in the MDE than HC group. The concurrent validity was supported by a positive correlation between scores of C-BRIAN-SR, Insomnia Severity Index and the Hospital Anxiety Depression Scale. C-BRIAN-SR negatively correlated MEQ in the MDE group (r = .30, p = 0.009), suggesting higher rhythm disturbances were associated with a tendency toward eveningness. A moderate test-retest reliability was found (r = .61, p < 0.001). A cut-off of 38.5 distinguished MDE subjects from HC with 82.9% of sensitivity and 81.0% of specificity. C-BRIAN-SR score normalized in remitted MDE patients but remained higher in the non-remitted. The C-BRIAN-SR is a valid and reliable scale for measuring the biological rhythms and may assist in the screening of patients with MDE.

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.

Personality Risk Factors for Vape Use amongst Young Adults and Its Consequences for Sleep and Mental Health

(1) Background: The surge in vape (e-cigarette) use among young adults is concerning, as there is limited knowledge about risk factors and health consequences. This study explores the personality traits linked to vape use, and associations between vaping and chronotype, sleep quality, and mental health, among young adults. (2) Methods: 316 participants, aged 18-25, completed measurements of mindfulness, rumination, self-compassion, anxiety/depression, chronotype, and sleep quality. (3) Results: the vape user group scored significantly lower on mindfulness, higher on rumination, and lower on self-compassion. Vape users were more likely to be evening types and had significantly lower sleep quality and higher anxiety symptoms, as well as higher alcohol use and loneliness (at trend) (4) Conclusions: These novel findings enhance our understanding of what might predispose young adults to vaping and the potential impact on their mental health and sleep quality. Findings point to specific cognitive/personality traits as vaping risk factors, which could inform intervention strategies.

Disruption of circadian rhythms promotes alcohol use: a systematic review

This systematic review investigates the bidirectional relationship between alcohol consumption and disrupted circadian rhythms. The goal of this study was to identify (i) the types of circadian rhythm disruptors (i.e. social jet lag, extreme chronotypes, and night shift work) associated with altered alcohol use and (ii) whether sex differences in the consequences of circadian disruption exist. We conducted a search of PubMed, Embase, and PsycINFO exclusively on human research. We identified 177 articles that met the inclusion criteria. Our analyses revealed that social jet lag and the extreme chronotype referred to as eveningness were consistently associated with increased alcohol consumption. Relationships between night shift work and alcohol consumption were variable; half of articles reported no effect of night shift work on alcohol consumption. Both sexes were included as participants in the majority of the chronotype and social jet lag papers, with no sex difference apparent in alcohol consumption. The night shift research, however, contained fewer studies that included both sexes. Not all forms of circadian disruption are associated with comparable patterns of alcohol use. The most at-risk individuals for increased alcohol consumption are those with social jet lag or those of an eveningness chronotype. Direct testing of the associations in this review should be conducted to evaluate the relationships among circadian disruption, alcohol intake, and sex differences to provide insight into temporal risk factors associated with development of alcohol use disorder.

Circadian preference and mental health outcomes in youth: A systematic review and meta-analysis

Youth is a vulnerable developmental period associated with an increased preference for eveningness and risk for developing psychopathology. Growing evidence suggests a link between eveningness and poorer mental health outcomes, but the findings in the current literature are inconsistent, and a comprehensive synthesis of evidence in this area remains lacking. This meta-analysis aimed to 1) synthesise the existing evidence on the association between circadian preference and mental health outcomes in youths and 2) explore potential sleep-related factors that may moderate the relationship between circadian preference and mental health outcomes. A systematic search of five electronic databases resulted in 81 observational studies included in the review. Eveningness was found to be significantly associated with general mental health (r = 0.20), mood-related disturbances (r = 0.17), and anxiety problems (r = 0.13). The qualitative review also identified that eveningness was associated with greater risks for psychotic symptoms and maladaptive eating behaviours. These findings highlighted the need to consider circadian preference in the clinical management of youth mental health problems. Further research is needed to examine the efficacy of a circadian-focused intervention in the context of youth mental health.

Is evening chronotype associated with higher alcohol consumption? A systematic review and meta-analysis

A broader understanding of whether and to what extent chronotype should be considered a risk factor for alcohol consumption is needed. The aim of this systematic review was to summarize the evidence on the association between evening chronotype and alcohol consumption. A systematic search of observational studies on this association was conducted in the PubMed, Scopus, Web of Science, Cochrane Library and PsycINFO databases up to April 30th, 2023. Random-effect models estimated the pooled odds ratio (OR) of alcohol consumption according to chronotype. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Quality Assessment tool for Observational Cohorts and Cross-sectional Studies from the National Heart, Lung and Blood Institute were followed. A total of 33 studies involving 28 207 individuals (age range: 18-93 years) were included in this review. Overall, most studies indicated a higher volume and frequency of alcohol consumption in evening-type individuals than in individuals with different chronotypes. Additionally, a meta-analysis including 13 studies showed that evening-type individuals were 41% more likely to consume alcohol than those with other chronotypes (OR = 1.41, 95% confidence interval: 1.16-1.66; I2 = 38.0%). Limitations of the present findings are the predominance of cross-sectional studies and varied definitions of alcohol consumption. The available evidence supports an association between the evening chronotype and alcohol consumption. The evening-type population, especially young adults, is a specific target for educational interventions for preventing or reducing alcohol consumption.PROSPERO number: CRD42022343778.

The subjective amplitude of the diurnal rhythm matters - Chronobiological insights for neuroimaging studies

Multiple aspects of human psychophysiology, including mood and cognition, are subjected to diurnal rhythms. While the previous magnetic resonance imaging (MRI) studies have focused solely on the morningness-eveningness (ME) preference dichotomy, i.e. the circadian phase, the second key dimension of the diurnal rhythms, i.e. the strength of these preferences (amplitude; AM), has been completely overlooked. Uncovering the neural correlates of AM is especially important considering its link with negative emotionality. Structural T1-weighted neuroimaging data from 79 early (EC) and 74 late (LC) chronotypes were analysed to compare grey matter (GM) volume and cortical thickness. The study aimed to elucidate whether the subjective AM and its interaction with ME was a significant predictor of individual brain structure. Both GM volume and cortical thickness of the left primary visual cortex was negatively correlated with AM scores across the entire sample. Furthermore, EC and LC differed in their association between AM scores and the GM volume in the right middle temporal gyrus, with the positive and negative correlations reported respectively in the two groups. The current study underlines the importance of the visual system in circadian rhythmicity and provides possible neural correlates for AM-related differences in negative affect processing. Furthermore, the presence of the opposite correlations between brain anatomy and AM in the two groups suggests that the behavioural and neuronal chronotype differences might become more pronounced in individuals with extreme diurnal differences in mood and cognition, highlighting the necessity to additionally account for AM in neuroimaging studies.

Associations between circadian misalignment and telomere length in BD: an actigraphy study

BACKGROUND

Life expectancy is significantly decreased in bipolar disorder (BD). This is associated with accelerated cellular aging which can be estimated by telomere length (TL). However, specific determinants of shorter TL in BD are under-explored. This study examines whether circadian misalignment (i.e. mismatch between preferred and actual phase of circadian activity rhythms) is associated with shorter TL in BD.

METHODS

Euthymic individuals with BD (n = 101) undertook 21 consecutive days of actigraphy recording and completed the Composite Scale of Morningness (CSM) to assess phase preference for activities (chronotype). Polymerase chain reaction was used to measure TL in blood. Cluster analysis identified circadian aligned/misaligned subgroups as defined by preferred (CSM score) and actual phases of activity (actigraphically determined onset of active and inactive periods). We tested for any associations between TL and clusters, with adjustments for between-cluster differences in socio-demographic and illness factors.

RESULTS

We identified three clusters: an "Aligned Morning" cluster (n = 31) with preferred and actual timing of activity in the morning, an "Aligned Evening" cluster (n = 37) with preferred and actual timing of activity in the evening and a "Misaligned" cluster (n = 32) with an evening chronotype, but an earlier objective onset of active periods. After adjustment for confounders, we found that TL was significantly associated with circadian misalignment and older age.

CONCLUSIONS

Circadian misalignment may partly explain shorter TL in BD and could contribute to accelerated aging in these individuals.

Sleep, substance misuse and addictions: a nationwide observational survey on smoking, alcohol, cannabis and sleep in 12,637 adults

For a good night's sleep, we consensually recommend avoiding alcohol, smoking and drugs. However, these addictions are highly prevalent in the general population, and it is difficult to estimate their real impact on sleep. The aim of this study is to clarify the association between sleep habits and disorders, and addictions. The design was a telephone crossover national recurrent health poll survey (Santé publique France, Baromètre santé, 2017; Questionnaire, pp. 53; Saint Maurice) in a representative sample of French adults. There were 12,367 subjects (18-75 years old) who answered the survey. Sleep log items assessed sleep schedules (total sleep time) on work and leisure days: at night, while napping, and over 24 hr using a sleep log. Retained items include: (1) short sleep (≤ 6 hr/24 hr); (2) chronic insomnia (International Classification of Sleep Disorders, 3^rd edition criteria); and (3) chronotype (evening-morning-neutral). Psychoactive substances retained included tobacco (current or former users), alcohol (daily consumption and weekly binge drinking), cannabis (Cannabis Abuse Screening Test), and other drugs (consumption during the past year). We found that: (1) daily smokers (lightly or heavily dependent) were more frequently short sleepers than occasional smokers and non-smokers; (2) heavily dependent daily smokers were more likely to suffer from insomnia than other smokers or non-smokers; (3) short sleep and insomnia were not significantly associated with the consumption of alcohol, cannabis or any other drug; (4) the evening chronotype was significantly associated with the consumption of tobacco, alcohol and cannabis. In conclusion, our study highlights significant relationships between the use of psychoactive substances and sleep characteristics among adults, emphasizing the need to take into account each subject individually.

Delayed circadian rhythms and substance abuse: dopamine transmission's time has come

Disrupted sleep and circadian rhythms are linked with substance abuse risk. Human studies that investigate relationships between sleep, circadian rhythm, and substance use reward generally rely on indirect means to infer dopaminergic function, such as functional magnetic resonance imaging. In this issue of the JCI, Zhang and colleagues used positron emission tomography (PET) to image striatal dopamine D1 (D1R) and D2/3 receptor (D/3R) availability in healthy adults. The authors assessed rest-activity rhythms, then conducted PET scans using radioligand antagonists selective for D1 receptors or D2/D3 receptors to measure D1R and D2/3R availability. They also measured the subjective drug effects of oral methylphenidate. Higher D1R availability in caudate and a greater methylphenidate reward sensitivity were associated with delayed rest-activity rhythms. Unexpectedly, lower overall activity was associated with higher D2/3R availability in the nucleus accumbens, which coincided with greater methylphenidate reward score. These findings may inform personalized prevention and/or treatment interventions.

Sleep and self-control: A systematic review and meta-analysis

Controlling impulses and overcoming temptations (i.e., self-control) are key aspects of living a productive life. There is a growing yet disperse literature indicating that sleep is an important predictor of self-control. The goal of this meta-analysis is to empirically integrate the findings from multiple literatures, and investigate whether sleep quality, and sleep duration predict self-control. To provide a thorough understanding of the proposed relationships, this meta-analysis also investigated potential differences between the level of analysis (between-individual vs. within-individual), research design (experiment vs. correlation; and cross-sectional vs. time-lagged), and types of measure (subjective vs. objective for sleep and self-control). A systematic review was conducted through ABI/Inform (including PsycInfo), ERIC, ProQuest Dissertation & Theses, PubMed, and Psychology Database using keywords related to self-control and sleep. Sixty-one independent studies met the inclusion criteria. The results, in general, suggest that sleep quality (between-individual 0.26, CI 0.21; 0.31; and within-individual 0.35, CI 0.24; 0.45), and sleep duration (between-individual 0.14, CI 0.07; 0.21; and within-individual 0.20, CI 0.09; 0.31) are all related to self-control. Given the impact of self-control on how individuals live productive lives, a future research agenda should include a deeper investigation in the causal process (potentially via prefrontal cortex activity) linking sleep and self-control, and an examination of the moderators (individual and contextual variables) that could impact the relationship between sleep and self-control.