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

Chronotype reflects individual differences in circadian preference along a morningness–eveningness continuum. Prior research links eveningness with adverse mental health outcomes (depression, anxiety, psychosis risk), as well as with personality traits such as higher neuroticism, schizotypy, and impulsivity; extraversion may be weakly associated with morningness. Eveningness is also associated with poorer sleep patterns, and poor sleep is common in mental disorders and among individuals with histories of childhood trauma. Recent large non-clinical studies suggest sleep quality relates more strongly to mental health than chronotype does, casting doubt on eveningness as an independent risk factor. The current study aimed to test associations between chronotype and mental health (depression, anxiety, stress) in young Indian adults, and to quantify the roles of sleep quality, personality traits (neuroticism, schizotypy, impulsivity, extraversion), and childhood trauma. The authors hypothesised that both eveningness and poorer sleep quality would relate to worse mental health, with stronger effects for sleep quality than chronotype, and explored whether sleep quality mediates links between chronotype and mental health while accounting for personality and childhood trauma.

The paper reviews evidence that eveningness correlates with depression, anxiety, psychosis risk, impulsivity, and substance use in non-clinical samples; personality traits linked to psychopathology (neuroticism, schizotypy, impulsivity) are often higher in evening types, whereas extraversion may be slightly higher in morning types. Eveningness is associated with poorer sleep quality and irregular sleep-wake patterns, which are themselves prevalent in mental disorders. Childhood maltreatment, especially emotional abuse/neglect, is associated with poor sleep and multiple psychiatric outcomes. Prior mediation work (e.g., UK samples) suggests the eveningness–depression link may be partially mediated by sleep quality, and that sleep quality shows stronger associations with mental and physical health than chronotype per se, particularly in females. However, no prior study had simultaneously quantified the roles of sleep quality, personality, and childhood trauma in a single, homogeneous non-clinical cohort.

Design and participants: Cross-sectional online survey of young adults residing in North India. Data were collected January–March 2023 (to minimise seasonal effects). Initial N=313 (age 18–40 years); 31 excluded for failed attention checks (n=20) or incomplete measures (n=11), yielding N=282 (195 females, 87 males). Inclusion: age 18–40, residing in India, fluent in English, not on regular medication, no diagnosed mental disorders, no non-prescribed drug use, provided informed consent. Ethics: Brunel University London REC (ref 41125-MHR-Mar/2023-44225-4). No compensation. Procedure: All self-reports completed online in a single session. Measures: - Chronotype: Morningness–Eveningness Questionnaire (MEQ; 19 items; higher scores=morningness; α=0.76 current sample). - Mental health: Depression Anxiety Stress Scales-21 (DASS-21) with Depression, Anxiety, Stress subscales (α in current sample: D=0.88, A=0.84, S=0.81). - Sleep quality: Pittsburgh Sleep Quality Index (PSQI; higher scores=worse sleep; α=0.67 current sample). - Personality: Eysenck Personality Questionnaire-Revised Short (EPQ-R-S): Extraversion and Neuroticism (good reliability), Psychoticism excluded due to low reliability (α=0.27). - Schizotypy: Short Oxford-Liverpool Inventory of Feelings and Experiences (sO-LIFE): Unusual Experiences, Cognitive Disorganisation, Introvertive Anhedonia, Impulsive Nonconformity (α=0.75, 0.81, 0.44, 0.54 respectively). - Impulsivity: Short UPPS-P (S-UPPS-P): Negative Urgency, Lack of Perseverance, Lack of Premeditation, Sensation Seeking, Positive Urgency (α=0.73, 0.55, 0.73, 0.66, 0.78). - Childhood trauma: Childhood Trauma Questionnaire-Short Form (CTQ-SF): Emotional, Physical, Sexual Abuse; Emotional, Physical Neglect (α=0.81, 0.87, 0.89, 0.82, 0.58). Additional demographics: ethnicity, BMI, stimulant/sedative use, education/employment. Statistical analysis: Data screened; distributions suitable for parametric tests. Sex differences assessed via independent t-tests. Pearson’s r used for associations between MEQ and mental health, sleep, personality, and childhood trauma; Fisher’s z used to compare correlation strengths (e.g., sleep vs chronotype with mental health; sex differences) with Bonferroni correction where applicable. Effect sizes per Cohen (small 0.10–0.29, medium 0.30–0.49, large ≥0.50). Structural Equation Modelling (SEM) in SPSS AMOS: Predictors included MEQ (chronotype), selected personality traits (Extraversion, Neuroticism, Cognitive Disorganisation, Lack of Perseverance, Lack of Premeditation, Sensation Seeking), and childhood Emotional Abuse and Emotional Neglect; mediator: PSQI (sleep quality); outcome: latent ‘Mental Health’ indicated by DASS Depression, Anxiety, Stress. Predictors allowed to covary; maximum likelihood estimation; multicollinearity checks (VIF<5, tolerance>0.2). Model fit indices: χ2/df, CFI (>0.95), TLI (>0.95), GFI (>0.95), AGFI (>0.90), RMSEA (close fit ~0.05). Significance of paths evaluated with bias-corrected 95% bootstrap CIs. Non-significant paths iteratively removed to yield final model. Multi-group invariance (male vs female) tested via comparison of unconstrained vs fully constrained models using Δχ2 (p>0.05), ΔCFI≤0.005, ΔRMSEA≤0.01; pairwise path comparisons conducted when needed.

Sample characteristics: - N=282 (195F/87M), 92.2% Asian Indian; 95.7% students. 55.3% classified as good sleepers (PSQI≤5), 44.7% poor sleepers. ~47.5% normal BMI, 46.45% underweight. - Females were younger and, compared to males, had higher morning preference (lower MEQ scores indicate eveningness; females showed higher morningness), poorer sleep quality, and higher mean scores on Neuroticism, Depression, Anxiety, Stress, Cognitive Disorganisation, Lack of Perseverance, Lack of Premeditation, and Emotional Abuse; males scored higher on Sensation Seeking, Positive Urgency, and Physical Neglect (all p≤0.039; many p<0.001). Correlations with chronotype (MEQ; lower=eveningness): - Eveningness associated with worse mental health: Depression r=-0.308 (p=0.001), Anxiety r=-0.213 (p=0.001), Stress r=-0.267 (p=0.001). - Eveningness associated with poorer sleep quality (PSQI): r=-0.389 (p<0.001). - Eveningness associated with personality/trauma: Neuroticism r=-0.299 (p=0.001), Cognitive Disorganisation r=-0.287 (p=0.001), Lack of Perseverance r=-0.181 (p=0.002), Lack of Premeditation r=-0.180 (p=0.002), Sensation Seeking r=-0.215 (p=0.001), Emotional Abuse r=-0.196 (p=0.001), Emotional Neglect r=-0.153 (p=0.001). Morningness associated with higher Extraversion r=0.222 (p=0.001). Correlations with sleep quality (PSQI; higher=worse): - Depression r=0.489, Anxiety r=0.474, Stress r=0.518 (all p<0.001). - Personality/trauma: Neuroticism r=0.433 (p<0.001), Unusual Experiences r=0.168 (p=0.001), Cognitive Disorganisation r=0.294 (p=0.001), Introvertive Anhedonia r=0.150 (p=0.012), Impulsive Nonconformity r=0.198 (p=0.001), Negative Urgency r=0.141 (p=0.017); Emotional Abuse r=0.377, Emotional Neglect r=0.275, Physical Abuse r=0.164 (all p≤0.006); Extraversion r=-0.125 (p<0.001). - Sleep–mental health correlations were significantly stronger than chronotype–mental health correlations: Depression z=2.55 (p=0.01), Anxiety z=3.53 (p<0.001), Stress z=3.54 (p<0.001). SEM mediation and model fit: - Initial model fit acceptable (χ2/df=2.11, RMSEA=0.06, GFI=0.97, AGFI=0.90, CFI=0.98), but with non-significant paths; final trimmed model showed excellent fit (χ2/df=1.18; GFI=0.98; TLI=0.99; CFI=0.99; RMSEA=0.02). - No direct effect of chronotype (MEQ) on mental health (β=-0.001, p=0.961). - Sleep quality fully mediated the eveningness–mental health relationship: indirect effect β=-0.10 (p<0.001) such that greater eveningness → poorer sleep → worse mental health. - Sleep quality partially mediated effects of Neuroticism (indirect β=0.11, p<0.001) and Childhood Emotional Abuse (indirect β=0.96, p<0.001) on mental health; no significant mediation for Cognitive Disorganisation (β=-0.04, p=0.427). Sex invariance: - Multigroup comparison indicated broad invariance (Δχ2(20)=25.87, p=0.156; ΔCFI=0.005), though ΔRMSEA=0.02 suggested some non-invariance; pairwise tests showed a stronger direct path from Cognitive Disorganisation to mental health in females (critical ratio=2.138, p<0.05). Overall: Eveningness showed small-to-medium associations with mental health and with certain personality traits/trauma, whereas sleep quality showed medium-to-large associations with mental health and mediated the chronotype–mental health link.

Findings indicate that in young Indian adults, eveningness relates to worse mental health primarily through poorer sleep quality, not via a direct pathway. Sleep quality exhibited substantially stronger associations with depression, anxiety, and stress than chronotype, aligning with recent evidence from Western samples and suggesting that previously publicised risks of eveningness may be contingent on sleep. Eveningness also correlated with higher neuroticism, impulsivity facets, and schizotypy (notably cognitive disorganisation), and with childhood emotional abuse/neglect; neuroticism and emotional abuse further influenced mental health indirectly via sleep quality. These results underscore sleep quality as a key mechanistic factor linking circadian preference to mental health and highlight potential targets for intervention (e.g., sleep-focused strategies) over attempts to shift chronotype. While females showed slightly more morningness on average, the structural relations were largely similar across sexes, with the exception of a stronger direct link from cognitive disorganisation to mental health in females.

The study found no direct association between eveningness and depression, anxiety, or stress in young adults; instead, poorer sleep quality fully mediated the chronotype–mental health relationship. Given sleep quality’s stronger links to mental health than chronotype, interventions promoting better sleep—especially for individuals with high neuroticism or histories of emotional abuse—may be more effective for improving mental health than strategies aiming to shift diurnal preferences. Future research should test these findings across cultures and age groups, incorporate objective circadian and sleep measures alongside self-reports, assess light exposure and hormonal influences, and employ longitudinal or repeated-measures designs to evaluate stability and causality.

• Cross-sectional, correlational design precludes causal inference. - Reliance on self-report measures without objective chronotype/sleep markers; light exposure not assessed. - Predominantly female sample; reproductive hormone fluctuations not measured. - Did not assess socioeconomic status, family dynamics, or cultural beliefs that may affect mental health. - Generalisability may be limited to young North Indian adults; may not extend to older or non-Indian populations. - Some scales (e.g., EPQ Psychoticism, certain sO-LIFE and S-UPPS-P subscales) showed lower reliability in this sample.