"seasonal affective disorder (sad) is characterized by the regular onset and remission of depressive episodes during the fall/winter months and remission during the summer. the present study compared psychological differences between subclinical sad and nondepressed (control) individuals and the seasonal stability of these differences. psychological characteristics that were assessed include explanatory style for negative outcomes (stability, globality, self-worth implications), coping styles in response to depressed mood (rumination, distraction, problem-solving, dangerous activities), personality style (sociotropy, solitude and independence), stress appraisal of winter stimuli, as well as response latency and immediate and delayed recall of sad, depressed, and neutral words presented during a modified stroop task. the results indicated that sad individuals ruminated more than control individuals during the winter; utilized more stable, global, and self-worth implicating (characterological) explanations; were more sociotropic; and exhibited a greater stress appraisal of winter stimuli. the sociotropy, stress appraisal of winter stimuli, and use of stable explanations in sad individuals did not change with the seasons. during the summer, sad individuals improved in their coping style (less rumination, more distraction and problem solving) and explanatory style (less global and self-worth implicating explanations). the temporal stability of the stress appraisal of winter stimuli suggests the presence of a unique cognitive schema associated with seasonal mood changes.