Diurnal variation of symptoms in seasonal affective disorder.

The classic melancholic pattern of depressive symptoms being worse in the morning was present in 3/4 of a sample of 47 seasonal affective disorder patients (SAD), as assessed by global ratings and self-ratings of diurnal variation (DV). The type of DV did not predict response to light, but it did predict relapse within a week: Only those SAD patients with symptoms worse in the evening or no DV did so.