Psychiatry Research 120 (2003) 53–59 0165-1781/03/$ - see front matter  2003 Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S0165-1781Ž03.00147-1 The Seasonal Pattern Assessment Questionnaire as a measure of mood seasonality: a prospective validation study Greg Murray* School of Social and Behavioural Sciences, Swinburne University of Technology, P.O. Box 218 John Street, Hawthorn 3122, Australia Received 27 December 2002; received in revised form 28 April 2003; accepted 25 May 2003 Abstract The aim of this study was to test the validity of the Seasonal Pattern Assessment Questionnaire (SPAQ) as a measure of winter pattern seasonality of mood in the general population. The criterion was four repeated measurements of mood, collected in summer and winter each year for 2 years in a longitudinal questionnaire study. To account for the imperfect reliability of SPAQ reports, the SPAQ was completed on two occasions, and aggregate SPAQ variables created. Three variables from the SPAQ were tested for their correlation with prospectively measured lowering of mood in winter: seasonal pattern type, Global Seasonality Score (GSS) and self-reported problems with seasonal variation. The sampling frame was the electoral roll in a suburban region of Melbourne, Australia. Complete four- wave data were obtained from 304 respondents (53.9% female). Seasonal pattern type (self-report as feeling worst in winter months) was the only SPAQ variable to show a significant association with prospectively measured winter pattern seasonality of mood. It is provisionally concluded that the SPAQ can function as a measure of seasonality of mood in the normal population, but that validity has only been confirmed for the relatively gross variable of seasonal pattern type.  2003 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Circa-annual rhythms; Winter depressions; Psychometrics 1. Introduction Seasonal affective disorder (SAD)(Rosenthal et al., 1984) is typically understood as the extreme end of a continuum of normative seasonal variation in mood and behaviour (Hardin et al., 1991). In fact it has been suggested that the individual tendency towards seasonal variation in mood (‘sea- sonality’) may have more empirical support than *Fax: q61-3-9819-0574. E-mail address: gwm@swin.edu.au (G. Murray). categorical SAD (Bauer and Dunner, 1993). Sea- sonality is, therefore, a variable of interest in its own right, as demonstrated by its prominence in numerous studies (e.g. Eagles et al., 2002; Gordon et al., 1999; Hebert et al., 2002; Perry et al., 2001). The Seasonal Pattern Assessment Questionnaire (SPAQ: Rosenthal et al., 1987) is a retrospective self-report instrument, originally designed to screen for SAD. Major strengths of the instrument are its brevity, high face validity and adequate psychometric properties (factor structure and test–