Associations between chronotype and psychiatric symptoms across the adult lifespan

Chronotype, the individual propensity towards morningness or eveningness, is a transdiagnostic factor implicated in mental health. How chronotype covaries with distinct psychiatric symptoms across the adult lifespan remains underinvestigated. In this cross-sectional study, 428 participants (18-70 years, evenly distributed across five age groups; 282 women, 143 men, other gender identity) completed the Reduced Morningness-Eveningness Questionnaire to approximate chronotype, and 11 validated scales assessing common psychiatric symptoms. Regression analyses and generalized additive models (GAMs) were used to examine linear and nonlinear relationships between chronotype, age, and psychiatric symptoms. Eveningness was associated with (in decreasing order of strength): emotion dysregulation, attention-deficit/hyperactivity disorder (ADHD), depression, autism, emotional instability, generalized anxiety, social anxiety, and impulsivity symptoms. Morningness was associated with mania symptoms. No significant associations were found between chronotype and delusional ideation or obsessive compulsive disorder (OCD) symptoms. Psychiatric symptom severity was generally lower with increasing age, particularly for emotional instability, emotion dysregulation, and ADHD. Nonetheless, certain symptoms persisted across age in eveningness (depression, generalized anxiety, OCD, ADHD), while other symptoms were lower (mania) or higher (social anxiety and delusional ideation) with eveningness at older ages. Except for mania symptoms, morningness in older age was not associated with higher symptom burden than eveningness for any other psychiatric domains. These results are consistent with the idea that morningness may be protective, being associated with lower psychiatric symptom levels in both younger and older age groups. In contrast, eveningness was associated with higher levels of autism, social anxiety and delusional ideation symptoms in older age.