Longitudinal study with a normal population demonstrates a strong seasonal effect on depression, hostility, anger and irritability

Many people believe that the season has an affect on depression and other mood states, but researchers have often reached inconsistent results when putting this widely held belief to the test. Now, a new longitudinal study involving over 600 adult members of a large health maintenance organization (HMO) has demonstrated a strong seasonal effect showing depression highest in winter and lowest in summer. This study by psychologist Morton G. Harmatz, Ph.D., and other researchers will be presented at the 107th Annual convention of the American Psychological Association in Boston. The researchers also found higher ratings of hostility, anger, irritability and anxiety in the winter.

Patients of the Fallon Healthcare System in Massachusetts were followed for a period of one year during which time measurements were made of medical and psychological variables during each season. For the 329 participants who provided scores in each season, there was a significant relationship between season of the year and mood. Feelings of depression, hostility, anger, irritability and anxiety were highest in the winter and lowest in the summer, with spring and fall being between the extremes. The seasonal effect occurred irrespective of the age or gender of the participants.

The researchers say additional research should focus on what factors are responsible for the seasonal mood differences. "Diet, activity, and light exposure all show seasonal variation and might, singly or in combination, be contributing factors to the seasonal effects demonstrated by these findings."

Presentation: "Seasonal Variation of Depression and other Moods: a Longitudinal Approach" by Morton G. Harmatz, Ph.D., Arnold D. Well, Christopher E. Overtree, Kathleen K. Kawamura, University of Massachusetts of Amherst and Ira S. Ockene, MD, and Milagros Rosal, Ph.D., University of Massachusetts Medical School, Session 1162, 12:00 PM - 1:50 PM, August 20, 1999, Hynes Convention Center, Exhibit Hall A, Poster B-8.

Dr. Harmatz can be reached at (413) 256-6028 or by email at [email protected] .

(Full text available from the APA Public Affairs Office.)

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