Publication date

Depression in the general practice: do weather conditions influence incidences?

Brake, H. te, Verheij, R. Depression in the general practice: do weather conditions influence incidences? Occhio Clinico: 2006(suppl. 6) 234. Abstract. 12th Regional Conference of the European Society of General Practice/Family Medicine: "Towards medical renaissance bridging the gap between biology and humanities", Florence, Italy on 27-30 August 2006.
Clinical studies have shown that seasonality in affective disorders exists. Even though most depressive disorders are managed exclusively by the GP, there is little population based research that has examined these seasonal influences in a primary care setting. Furthermore, little is known about the contribution of weather conditions to these seasonal variations. This study aims to examine seasonal effects on the incidence of depression in general practice. By including meteorological data in the analysis, the influence of actual weather conditions within seasons is also assessed. In the Netherlands, every patient is listed with one GP (fixed list system). We used ICPC coded electronic medical records (2001-2004) from a representative group of 53 to 70 GPs with, on average, 250000 patients. Meteorological data was provided by the Royal Netherlands Meteorological Institute. Preliminary results show that the relative percentage of depression (ICPC code P76) was significantly higher in winter (1.22%) than in summer (1.14%). Remarkably, in winter, no association was found between diagnosis depression and any meteorological circumstances. The amount of light (i.e., hours of sunshine and cloudiness) showed a significant correlation in summer (R = 0.3 - 0.4), while the effects of temperature were most pronounced in autumn (R = 0.3). These initial results indicate that seasonality is also present in a primary care setting, and that the weather conditions have an independent effect within the seasons. Further analyses on the exact incidences of depression will be presented. (aut.ref.)