Seasonal affective disorder: report from India (latitude 26 degrees 45'N).

BACKGROUND: A number of studies have established the entity of seasonal affective disorder (SAD) and delineated the presence of atypical depressive features of carbohydrate craving, hyperphagia and hypersomnia. Most literature has emanated from research carried out in temperate climates, and only few reports are available from tropical countries, especially India.
METHODS: Consecutive patients with recurrent mood disorder (who had at least 2 episodes of depression in the past) comprised the study sample. The diagnosis of mood disorder was made according to DSM-III-R criteria. The sample was divided into two groups - seasonal and non-seasonal according to the DSM-III-R criteria of seasonal pattern. The depressed patients were rated on SADD and HDRS, and manic patients on BRMRS.
RESULTS: Eighteen of 93 patients fulfilled the criteria of seasonal pattern; 7 of these seasonal patients, and 25 of the non-seasonal patients were currently in depressive phase. Males dominated the sample in both the groups. The seasonal and non-seasonal groups as regards symptomatology, differed only on a few items - decreased libido on SADD, and suicidal ideation and helplessness on HDRS. Atypical vegetative features were not seen in any of the seasonal patients.
CONCLUSIONS: SAD is seen at lower latitudes also, although atypical vegetative features are not a prominent part of the symptomatology. LIMITATIONS: The study sampled was obtained from a very select population, and thus does not indicate the prevalence of SAD in India. Secondly, the small sample size precludes any categorical comments of the symptomatology. Moreover, winter and summer depressives were considered as one group. CLINICAL RELEVANCE: Emphasising the presence of SAD in a tropical country where there is relatively less variation in daylight periods, this report forms a base for future studies. It also raises the question of the role of variations in daylight in the aetiology SAD.