Introduction The interrelationship of obesity and depression is not fully elucidated. Treatment strategies that target recovery of the homeostatic balance, might offer opportunities for patients that suffer from the co-occurrence. We tested whether a 75wk combined lifestyle intervention with cognitive behavioral therapy (CLI+) has a beneficial effect on both obesity and depressive symptoms.

Method Patients with obesity (n=123, 75% female) were recruited at the obesity center CGG (Centrum Gezond Gewicht, Erasmus MC), a multidisciplinary tertiary referral center for patient-tailored diagnostics and treatment. Inclusion criteria were: lifestyle-related obesity, BMI >30 kg/m², age ≥18 years and ≥1 obesity-related comorbidity. Patients were excluded when underlying causes of obesity were detected that necessitated individual treatment, e.g., clinical depression. The CLI+ was completed after 75wks of guidance, in groups of 10-12 patients. An intermediate assessment took place after 10wks. We analyzed changes in Hospital Anxiety and Depression Scale (HADS) scores and Impact of Weight on Quality of Life (IWQoL) scores, in association with change in weight and waist circumference, over time.

Results Both HADS and IWQoL scores improved over time, with sex-differences observed in HADS scores. In longitudinal analyses, these effects were associated with the decrease in weight and waist circumference.

Conclusion Patients with obesity that were treated with our in-house CLI+ experienced a significant improvement of both their obesity, depressive symptoms and weight-related quality of life. Accordingly, a CLI+, that is proven to be effective for lifestyle-related obesity, might be used to treat the co-occurrence of obesity and depression in adults. Studying group characteristics of patients that benefit most of such an approach is warranted.