The use of the Internet as a research tool: the nature and characteristics of seasonal affective disorder (SAD) amongst a population of users

Seasonal affective disorder (SAD) is a cyclical syndrome characterized by recurrent episodes of autumn or winter depression and atypical depressive symptoms. This paper describes the characteristics of an international sample of 425 Internet users who responded to newsgroup advertisements seeking people who experienced seasonal changes in mood and behaviour, and completed a modified version of the Seasonal Patterns Assessment Questionnaire. The relationship between SAD and latitude and the relatively novel use of the Internet as a means of data collection are discussed, with emphasis upon the theoretical, methodological and ethical issues encountered during such research. (C) 1997 Elsevier Science B.V.