Antidepressant use before and after initiation of diabetes mellitus treatment

Although current literature suggests an association between diabetes and depression, the direction of the association is unclear. We examined the temporal association between diabetes and depression by studying antidepressant and benzodiazepine use around the initiation of diabetes treatment.

From a pharmacy registry database we selected 49,593 diabetic patients and a random sample of non-diabetic individuals (n = 154,441), all >40 years old. Antidepressant and benzodiazepine use was calculated for the 7 years before and 7 years after the index date. The index date in diabetes patients was defined as the date of initiation of diabetes medication. A random index date was assigned to non-diabetic individuals. Time-specific incidence rate ratios of antidepressant and benzodiazepine use were calculated for intervals of 1 year, 3 months and 1 month.

Antidepressant and benzodiazepine use was increased 2 months before and 3 months after the initiation of diabetes treatment compared with non-diabetic individuals. The strongest increase in incidence of antidepressant and benzodiazepine use was seen in the month after initiation of diabetes treatment with incidence rate ratios of 2.4 (95% CI 2.0-3.0) and 3.4 (95% CI 3.0-3.8) respectively, after adjustment for age, sex and Chronic Disease Score.

The increased incidence of antidepressant and benzodiazepine use may be a consequence of the burden of disease, of starting with diabetes medication or of being diagnosed with diabetes. Our findings could also reflect earlier detection by their physician.