Send to

Choose Destination
Psychiatry Res. 1990 Feb;31(2):131-44.

Prevalence of seasonal affective disorder at four latitudes.

Author information

Uniformed Services University of the Health Sciences, Bethesda, MD.


The Seasonal Pattern Assessment Questionnaire (SPAQ) was mailed to a sample population balanced for sex and randomly selected from local telephone directories in four areas: Nashua, NH, New York, NY, Montgomery County, MD, and Sarasota, FL. On the basis of responses to this questionnaire, prevalence rates of winter seasonal affective disorder (winter SAD), summer seasonal affective disorder (summer SAD), and subsyndromal winter SAD were estimated for the four areas. Rates of winter SAD and subsyndromal SAD were found to be significantly higher at the more northern latitudes, while no correlation was found between latitude and summer SAD. The positive correlation between latitude and prevalence of winter SAD applied predominantly to the age groups over 35.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center