Chronotype distribution and stability in hospitalized patients with depression

Introduction: Circadian preference (chronotype) is assumed to be a rather stable trait with the “morningness-eveningness” dimension showing a normal distribution in most general population samples. Eveningness seems to be related to depressive disorders. The distribution and stability of morningness-eveningness was investigated in hospitalized patients with affective disorder. Methods: In patients with depressive disorder (85% major depression; 15% depressive adjustment disorder), chronotype was assessed with the Morningness-Eveningness Questionnaire (MEQ) after admission, and in a subsample of patients again before discharge. Distribution and stability of MEQ scores were analyzed. Results: MEQ scores (mean 49 ± 11, range 23–75, higher scores indicating morningness) in n = 93 acutely depressed inpatients (age 41 ± 14y; 63% women; hospitalization 48 ± 22 d) were normally distributed (Kolmogorov-Smirnov test, n. s.) with 59% intermediate types, 19% evening types, and 22% morning types. In n = 19 patients, MEQ change scores from admission to discharge were non-significant (−1.3 ± 5.0); scores at admission and discharge were highly correlated (r = 0.82; P < 0.001). Conclusions: According to our findings evening types were not clearly overrepresented in patients with depression. MEQ scores were rather stable in depressed inpatients.