PURPOSE: Anecdotal evidence suggests that antidepressants (ADs) may complicate glycaemic control. The objective of this longitudinal study was to investigate the influence of ADs on glycaemic control within diabetes patients. METHODS: From the pharacy registry database PHARMO, we selected insulin users who did not use oral antidiabetics. The study population comprised: 133 patients with at least 12 months insulin use before and 6 months during an AD episode, including 56 patients with an additional 6 months of insulin use after the AD episode; 180 patients with 24 months insulin use without an AD episode. Glycaemic control was measured as the amount of insulin used, which was calculated intra-individually in 3-month periods. We stratified for selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). RESULTS: Mean age (s.d.) of the subjects was 53.9 (19) years; 46.9% were men. Overall, the amount of insulin used did not change during or after AD use. No-AD users showedan increase of 16% in amount of insulin used over a period of 2 years (p < 0.001). SSRI users showed a decrease of 13% in amount of insulin used during the AD episode (p = 0.029), while no change was seen in TCA users. Notable was the large intra- and interindividual variation in amount of insulin used across all groups. CONCLUSIONS: Overall, AD use did not influence glycaemic control in diabetes patients. The tendency for a difference between SSRIs and TCAs is suggestive for a pharmacologic effect ofADs rather than a general effect of depression on glycaemic control.