[Socio-economic position: more than a background characteristic in psychiatry]

Background Mental illness is more common and has a less favorable course in people with a low socioeconomic position (SEP). Aim To clarify the concept of SEP and what mechanisms underlie socioeconomic differences in mental illness. Method Review of theoretical and empirical scientific research. Results For determining socioeconomic differences in mental illness, it matters whether one looks at educational level, occupational level, or income. Mechanisms of social causation and social selection play a role. Among other mechanisms, SEP contributes to mental illness through exposure to stressors, unfavorable living conditions, unhealthy behaviors, and social exclusion. Conversely, mental health problems can negatively influence SEP. Conclusion Researchers and practitioners should be aware that SEP is more than a background characteristic of a patient or a statistical control variable; over the life course there is a complex interaction between SEP and both the etiology and course of mental illness.