Circadian typology and the Alternative Five-Factor Model of personality

Circadian preference is associated with multiple domains of trait and state level impulsivity

Impulsivity is a multidimensional construct with well-documented risk for substance use problems at both the trait- and state levels. A circadian preference towards eveningness has been linked to trait-level, global impulsivity, but whether this association holds true across multiple dimensions of impulsivity and whether actual sleep timing shows parallel associations with impulsivity remain unclear. Here, we extend existing literature by investigating whether eveningness is associated with multiple facets of both trait- and state-level impulsivity. We also examined these associations utilizing daily measures of sleep timing and duration and explored whether they differed by sex and/or race. All participants were moderate-to-heavy social drinkers aged 21-35. Primary analyses included 78 participants (100% White male participants: Sample 1) with circadian preference data (Composite Scale of Morningness: CSM) and sleep timing (midsleep) and duration assessed via daily self-report over 10 days. Five facets of impulsivity were assessed via the UPPS-P, both at baseline (full scale; trait-level) and up to 6 times per day over 10 days (reduced scale; state-level). Linear regression and mixed-effects models were used to examine between- and within-person associations of impulsivity with measures of circadian preference, timing, and duration, accounting for covariates. Exploratory analyses combined Sample 1 with an additional more diverse sample (Sample 2), resulting in a total of 182 participants (29.1% self-identified as Black, 29.7% as female) with daily self-report sleep timing and duration only (no circadian preference). Primary between-person models found that eveningness was associated with multiple facets of impulsivity, at trait (lack of perseverance) and state levels (negative and positive urgency, lack of perseverance, and lack of premeditation), while average midsleep and duration were generally unrelated to impulsivity. Primary within-person models largely paralleled the between-person findings. Exploratory analyses in the larger combined Samples 1 and 2 (without circadian preference) found that later midsleep timing was associated with greater mean state-level impulsivity across multiple facets, associations that may differ by race and sex. In a sample of White male participants, circadian preference for eveningness was strongly associated with multiple facets of impulsivity, at both trait- and state-levels, which may contribute to risk for substance use. Preliminary findings suggest sex and race differences in sleep-impulsivity associations, but future research with objective sleep/circadian measures in larger, more diverse samples will be important to clarify implications for sleep-focused prevention and/or treatment of substance use.

Investigating the relationship between personality, chronotype, computer game addiction, and sleep quality of high school students: A structural equation modelling approach

This study examines the relationship between high school students' age, gender, personality, computer game addiction, chronotype, and sleep quality using structural equation modelling. For this purpose, the study was planned according to the correlational research design, one of the most common quantitative research methods. The sample of the study consisted of 922 students who accepted to participate and completed the scales. Of the 922 high school students in the sample, 528 were girls, and 394 were boys. In the study, the Computer Game Addiction Scale for Adolescents, Sleep Quality Scale, Composite Scale of Morningness (CSM), and Big Five Inventory were used to measure the variables. Among the variables involved, personality traits, such as consciousness, neuroticism, and openness to experience, were significantly related with morningness-eveningness. Besides, gender and being evening or morning types were found to be significantly related with game addiction. However, sleep quality was predicted by computer game addiction and morningness-eveningness. It was found that the fit indices of the model have an acceptable and good fit in explaining the variables.

Personality Profile and Clinical Correlates of Patients With Substance Use Disorder With and Without Comorbid Depression Under Treatment

Background: Among patients with substance use disorder (SUD), major depressive disorder (MDD) is highly prevalent. Even though, personality plays an important role in treatment outcomes for individuals with SUD and SUD + MDD, few studies have explored personality characteristics in these samples. This study aims to describe personality for patients with SUD taking into account the comorbid MDD, using the Alternative Five Factor Model (AFFM). We also aim to compare SUD + MDD patients with population norms and to elucidate possible personality clinical correlates. Methods: For our study, 116 male patients undergoing for SUD treatment were divided in two groups: SUD only (N = 58) and SUD + MDD (N = 58). To examine personality, we used the Zuckerman-Kuhlman Personality Questionnaire and multiple analyses of covariance were performed to identify differences. In a first analysis, age was introduced as a covariate whereas in a second analysis the continuous variables that showed to have a discriminant value for the groups were added as covariates. Variables predicting the presence of dual diagnosis and personality clinical correlates were analyzed by logistic and linear regression models, respectively. We observed that patients with SUD + MDD show distinctive personality characteristics compared with patients with SUD only and population norms. Results: According to the AFFM, SUD + MDD patients are characterized by higher Neuroticism-Anxiety (positively associated to depressive symptoms) and Impulsivity; and by lower Parties and Friends. Moreover, the probability of having a dual depressive disorder was represented by the amount of medications and substances used. The preference for hard work and the energy self-reported levels (Work Activity trait) are linked to these clinical variables rather than to the presence/absence of a dual depressive disorder. Conclusions: Even when controlling clinical variables related to a higher probability of having a dual depressive disorder, the Neuroticism-Anxiety is a personality trait that strongly differentiates between SUD only and SUD + MDD patients. Further investigation is needed to explore the role of this personality trait as endophenotype in dual depressive men. Our results underline the importance of a dimensional understanding of personality and its clinical correlates among patients with SUD + MDD; this approach could provide us information on specific treatment strategies to improve the prognosis of patients.

Eveningness among late adolescent males predicts neural reactivity to reward and alcohol dependence 2 years later

Eveningness, a preference for later sleep-wake timing, is linked to altered reward function, which may explain a consistent association with substance abuse. Notably, the extant literature rests largely on cross-sectional data, yet both eveningness and reward function show developmental changes. We examined whether circadian preference during late adolescence predicted the neural response to reward 2 years later. A sample of 93 males reported circadian preference and completed a monetary reward fMRI paradigm at ages 20 and 22. Primary analyses examined longitudinal paths from circadian preference to medial prefrontal cortex (mPFC) and ventral striatal (VS) reward responses. We also explored whether reward responses mediated longitudinal associations between circadian preference and alcohol dependence, frequency of alcohol use, and/or frequency of cannabis use. Age 20 eveningness was positively associated with age 22 mPFC and VS responses to win, but not associated with age 22 reactivity to reward anticipation. Age 20 eveningness was indirectly related to age 22 alcohol dependence via age 22 mPFC response to win. Our findings provide novel evidence that altered reward-related brain function could underlie associations between eveningness and alcohol use problems. Eveningness may be an under-recognized but modifiable risk factor for reward-related problems such as mood and substance use disorders.