Background: There is increasing recognition of the importance of addressing clinical depression in patients with Type 1 or Type 2 diabetes. Depression in people with Type 1 or Type 2 diabetes has been associated with increased blood glucose levels, risks of complications and mortality and poorer self-management of diabetes and quality of life (1). However, few studies have examined the impact of mild (‘subthreshold’) depression in patients with diabetes.
Aims: This observational study aimed to compare three groups of adults with Type 1 or Type 2 diabetes – those with i) no symptoms of depression, ii) mild symptoms of depression and iii) moderate-to-severe symptoms of depression – on a range of variables. Specifically, we aimed to compare the three groups on diabetes-related distress, anxiety and somatic symptoms, quality of life and HbA1c.
Method: 244 adults attending two hospital diabetes services in 2007-8 completed self-report measures assessing severity of depression, anxiety, and somatic symptoms (Patient Health Questionnaire), diabetes-related distress (Problem Areas in Diabetes) and quality of life (SF12). Clinical interviews with a psychiatrist examined past and current mental health. HbA1c levels on the day of recruitment were recorded from case notes. Participants were divided into three groups based on the severity of their depression scores on the PHQ-9 self-report measure.
Results: Compared to those with no symptoms of depression, participants with mild depression had significantly higher levels of diabetes-related distress, anxiety, somatic symptoms and mental-health related quality of life. The ‘moderate-severe depression’ group scored the most severely on each of these measures. The three groups did not differ significantly on HbA1c.
Conclusion: Even mild depression in patients with Type 1 or Type 2 diabetes is associated with higher levels of diabetes-related distress and anxiety and lower quality of life. Screening for mild depression, well as clinical depression, may be helpful in diabetes services.