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Seasonality in Major Depressive Disorder: Effect of Sex and Age
Matthäus Fellinger1, Thomas Waldhör2, Alessandro Serretti3
1Clinical Division of Social Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
Background:
Aside from the concept of seasonal affective disorder, the evidence for a seasonal pattern (SP) of major depressive disorder (MDD) is controversial. Furthermore, the effect of sex and age is still unclear.
Methods:
This is a nationwide, registry-based study assessing all inpatient admissions in mental health hospitals due to MDD episodes according to ICD-10 (moderate (F32/33.1), severe (F32/33.2) and severe with psychotic features (F32/33.3)) in Austria across 14 years. Calculations were based on deviations from expected monthly admissions.
Results:
The sample comprised 231,824 hospitalisations (36.8% men) for MDD. A significant SP (p=0.001) in moderate and severe depressive episodes in both women and men with decreased admission rates in the summer months and December was detected. In psychotic depression a significant SP was only evidenced in women (p = 0.002, men: p = 0.291). Patients older than 55 years had a reduced SP compared to those being younger.
Limitations:
Only anonymised admission data of inpatient treatments were available. Hospitalization rates cannot fully be equated to the occurrence of MDD.
Conclusions:
The current study indicates a seasonal variation in MDD symptoms that may go beyond seasonal affective disorder. Knowledge about the predictability of depressive symptoms in patients should encourage preventive strategies.
Insights
Major depressive disorder (MDD) shows seasonal patterns, with fewer hospital admissions in summer and December. This seasonal variation in depression may extend beyond seasonal affective disorder, informing preventive strategies.
Area of Science:
- Psychiatry
- Epidemiology
- Mental Health Research
Background:
- The existence of a seasonal pattern in major depressive disorder (MDD) beyond seasonal affective disorder (SAD) remains debated.
- The influence of sex and age on seasonal variations in MDD is not well-established.
Purpose of the Study:
- To investigate the seasonal pattern (SP) of major depressive disorder (MDD) across different severities and patient demographics.
- To determine if seasonal variations in MDD extend beyond the scope of seasonal affective disorder.
Main Methods:
- A nationwide registry-based study analyzed 14 years of inpatient mental health admissions for MDD in Austria.
- Data included moderate, severe, and severe with psychotic features MDD episodes (ICD-10 codes F32/33.1-3).
- Calculations focused on deviations from expected monthly admission rates.
Main Results:
- A significant seasonal pattern (p=0.001) was observed in moderate and severe MDD, with lower admission rates during summer and December for both sexes.
- Psychotic depression exhibited a significant seasonal pattern only in women (p=0.002).
- Individuals over 55 years old demonstrated a reduced seasonal pattern compared to younger patients.
Conclusions:
- The study confirms a seasonal variation in MDD symptoms that may be broader than previously understood, extending beyond seasonal affective disorder.
- Understanding the predictability of depressive symptoms seasonally can aid in developing proactive and preventive mental health strategies.
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