Seasonal affective disorder among primary care attenders and a community sample in Aberdeen

There are no large published studies of the prevalence of seasonal affective disorder (SAD) among UK populations. To determine the prevalence of SAD among patients attending a general practitioner (GP). Patients aged 16-64 consulting their GPs in Aberdeen during January were screened with the Seasonal Pattern Assessment Questionnaire (SPAQ). SPAQs were also mailed to 600 matched patients, who had not consulted their GP during January. Surgery attenders who fulfilled SPAQ criteria for SAD were invited for interview to determine whether they met criteria for SAD in DSM-IV and the Structured Interview Guide for the Hamilton Rating Scale for Depression--Seasonal Affective Disorder Version (SIGH-SAD). Of 6161 surgery attenders, 4557 (74%) completed a SPAQ; 442 (9.7%) were SPAQ cases of SAD. Rate of caseness on the SPAQ did not differ between surgery attenders and non-attenders. Of 223 interviewed SPAQ cases of SAD, 91 (41%) also fulfilled DSM-IV and SIGH-SAD criteria. There is a high prevalence of SAD among patients attending their GPs in January in Aberdeen; this is likely to reflect a similar rate in the community.