The purpose of the present study has been to assess the societal cost of major depression and the distribution into different cost components. The impact of adherence and treatment response was also explored.

Data were collected from a randomized controlled trial of patients with major depressive disorder who were treated in a naturalistic primary care setting. Resource use and quality of life were followed during the two-year trial.

The mean total cost per patient during two years was KSEK 363 (EUR 38 953). Indirect costs were the most important component (87%), whereas the cost of drugs was minor (4.5%). No significant differences in costs or quality of life between treatment arms or between adherent and non-adherent patients were demonstrated. However, treatment responders had 39% lower total costs per patient and experienced a larger increase in quality of life compared to non-responders.

Major depression has high costs for society, primarily due to indirect costs. Treatment responders have considerably lower costs per patient and higher quality of life than non-responders. This indicates that measures to increase response rates are also important from an economic perspective.