The key diagnostic criteria for Seasonal Affective Disorder (SAD) in adults include the presence of a recurrent major depressive episode that occurs with a seasonal pattern, typically beginning in autumn or winter and remitting in spring or summer. This seasonal pattern must have been observed for at least two consecutive years without non-seasonal depressive episodes during the same period.
Symptoms commonly include low mood, anhedonia, hypersomnia, increased appetite (especially craving carbohydrates), weight gain, and social withdrawal. These symptoms cause significant distress or impairment in social, occupational, or other important areas of functioning.
It is essential to exclude other psychiatric disorders or medical conditions that could explain the seasonal pattern of symptoms. The diagnosis is clinical, based on history and symptom pattern, as there are no definitive laboratory tests.
These criteria align with the ICD-10 and DSM-5 specifiers for seasonal pattern in major depressive disorder, as well as UK clinical guidelines on depression management. The literature emphasizes the importance of the temporal relationship of symptoms to seasons and the reproducibility of this pattern over multiple years Magnusson & Partonen 2005Thaler et al. 2011 NICE NG222.
Key References
- NG222 - Depression in adults: treatment and management
- CG91 - Depression in adults with a chronic physical health problem: recognition and management
- (Magnusson and Partonen, 2005): The diagnosis, symptomatology, and epidemiology of seasonal affective disorder.
- (Thaler et al., 2011): Second-generation antidepressants for seasonal affective disorder.
- (Nussbaumer-Streit et al., 2021): Second-generation antidepressants for treatment of seasonal affective disorder.