• DSM-III-R criteria, applied retrospectively in a research-oriented psychiatric clinic, identified patients (N=146) with a mood disorder and a seasonal pattern of recurrence (seasonal mood disorder). The seasonal mood disorder syndrome was not rare (10% of all mood disorders); diagnostic distribution was as follows: recurrent depression, 51%, and bipolar disorder, 49%, with 30% of the latter having mania (bipolar disorder type I) and 19% having hypomania (bipolar disorder type II). Most patients were women (71%); onset age averaged 29 years, with a mean of eight cycles in 12 years of illness; mean episode duration was 5.0 months. Mood disorder was found in a high proportion (68%) of the families. All but one patient followed one of two seasonal patterns in equal frequency: type A, fall-winter depression with or without spring-summer mania or hypomania; and type B, spring-summer depression with or without fall-winter mania or hypomania. Both types showed consistent times of onset and remission. These results emphasize that DSM-III-R seasonal mood disorder includes severe cases of recurrent depression and bipolar disorder and support a distinction between two seasonal subtypes.
Faedda GL, Tondo L, Teicher MH, Baldessarini RJ, Gelbard HA, Floris GF. Seasonal Mood DisordersPatterns of Seasonal Recurrence in Mania and Depression. Arch Gen Psychiatry. 1993;50(1):17–23. doi:10.1001/archpsyc.1993.01820130019004