The effects of weather on depressive symptoms in patients after cardiac surgery

Patients with cardiovascular disease have depression more often than the general population does. The aim of the study was to detect the associations between the psychological state and weather variables in patients who underwent coronary artery bypass grafting or valve surgery. The prospective study was performed during 2008-2012 in Kaunas, Lithuania. The psychological state of 233 patients was assessed by using the Symptom Checklist-90-Revised instrument. The assessment was carried out at 1.5 months, 1 year, and 2 years after the surgery. A sample of 531 measurements of psychological states was used. To investigate the relationships between psychological scores and daily weather variables, a mixed linear model was used adjusting for sex, the type of surgery, age, the marital status, the presence of arterial hypertension, diabetes, major depressive disorders, dysthymic disorders, agoraphobia, smoking before surgery, and myocardial infarction in the anamnesis. The mean somatisation score and air temperature on the second day prior to the survey were found to have a negative correlation in the multivariate model. Lower mean scores of anxiety and depression were linked to hotter days (air temperature >16.25°C on the second day) that did not occur in July or August. During colder days (air temperature <0.35°C), a higher mean score of anxiety and phobic anxiety was observed. A higher mean score of somatizations, depression, and anxiety was seen on the second day after the day with wind speed ≤2.85 kt and on the day after the day with relative humidity <66%. Both a decrease and an increase in daily atmospheric pressure were associated with a higher depression score. Our results confirm that among patients after open heart surgery, psychosomatic complaints are related to some weather changes. The obtained results can help to determine the complexity of weather patterns linked to poorer psychological health.