Relationships between demographic-, treatment-, and sickness-related factors, metabolic control (HbA1c), perceived burden of illness, and degree of depressive symptoms were examined in a group of 155 insulin-dependent diabetic patients, aged 35.3 +/- 8.9 years. The patients completed a questionnaire measuring depressive symptoms and three aspects of perceived burden of illness. No gender differences in HbA1c level or occurrence of late diabetic complications were found. Both men and women showed a modestly elevated degree of depression compared with norm groups. Self-reported burden of illness was strongly related to depression but was largely unrelated to objective disease-related measures. Level of depression was correlated neither with degree of metabolic control nor with the presence of such late diabetic complications as retinopathy and nephropathy. Some 44% of the variance in depression could be explained by worries about complications in those patients with the lowest HbA1c levels, by perceived restrictions in everyday life in patients with intermediate metabolic control, and by problems of glycaemic regulation in patients with poor metabolic control. Degree of depression was largely unrelated to disease severity, but was found to be related to the perceived daily burden of living with the disease, the specific worries and concerns associated with a depressed mood varying with degree of metabolic control.