A comparison of normal, bipolar and seasonal affective disorder subjects using the Seasonal Pattern Assessment Questionnaire.

The Seasonal Pattern Assessment Questionnaire is an instrument for retrospective self-rating of change in mood and vegetative functions with the seasons. It has been used in studies to identify and characterise patients with Seasonal Affective Disorder (SAD) in three countries. In this paper, the test-retest reliability of all items and the sensitivity to differences between groups have been investigated. Clear differences were found between the SAD group and a normal group. A group of bipolar affective disorder patients had intermediate scores on reported seasonal changes between the normal and SAD groups. All groups reported significant changes in mood and vegetative functions during the winter in the direction symptomatic for SAD suggesting that SAD patients may suffer an exaggerated form of a normal seasonal variation.