Depressive symptomatology differentiates subgroups of patients with seasonal affective disorder

Patients with seasonal affective disorder (SAD) may vary in symptoms of their depressed winter mood state, as we showed previously for nondepressed (manic, hypomanic, hyperthymic, euthymic) springtime states [Goel et al., 1999]. Identification of such differences during depression may be useful in predicting differences in treatment efficacy or analyzing the pathogenesis of the disorder. In a cross-sectional analysis, we determined whether 165 patients with Bipolar Disorder (I, II) or Major Depressive Disorder (MDD), both with seasonal pattern, showed different symptom profiles while depressed. Assessment was by the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version (SIGH-SAD), which includes a set of items for atypical symptoms. We identified subgroup differences in SAD based on categories specified for nonseasonal depression, using multivariate analysis of variance and discriminant analysis. Patients with Bipolar Disorder (I and II) were more depressed (had higher SIGH-SAD scores) and showed more psychomotor agitation and social withdrawal than those with MDD. Bipolar I patients had more psychomotor retardation, late insomnia, and social withdrawal than bipolar II patients. Men showed more obsessions/compulsions and suicidality than women, while women showed more weight gain and early insomnia. Whites showed more guilt and fatigability than blacks, while blacks showed more hypochondriasis and social withdrawal. Darker-eyed patients were significantly more depressed and fatigued than blue-eyed patients. Single and divorced or separated patients showed more hypochondriasis and diurnal variation than married patients. Employed patients showed more atypical symptoms than unemployed patients, although most of the subgroup distinctions lay on the Hamilton Scale. These results comprise a set of biological and sociocultural factors-including race, gender, and marital and employment status-which contribute to depressive symptomatology in SAD. Significant mood and sociocultural factors, in contrast to biological factors of gender and eye color, were similar to those reported for nonseasonal depression. Lightly pigmented eyes, in particular, may serve to enhance photic input during winter and allay depressive symptoms in vulnerable populations.