Cold summer weather, constrained restoration, and the use of antidepressants in Sweden

Constraint of restorative activities prolongs chronic stress and may exacerbate depressive symptoms. Treating unseasonable weather as an ecological constraint on restorative activities in outdoor settings, we investigated the relationship between cold summer temperatures and the dispensation of selective serotonin reuptake inhibitors (SSRIs) in Sweden. We obtained nationally aggregated data on defined daily doses of SSRIs dispensed monthly from 1991 through 1998. We analyzed the data using autoregressive, integrated, moving average time-series modeling methods. Dispensation of SSRIs correlated negatively with monthly mean temperature for July, the peak vacation period. The association held for both men and women, net of trends, seasonality, and other statistical controls. The constrained restoration hypothesis augments response style, restricted activity and seasonality explanations for depression. The study provides a novel perspective on green spaces and other outdoor settings as mental health resources. (c) 2007 Elsevier Ltd. All rights reserved.