Incidence and risk factors for depression and anxiety disorders: results from a 34-year longitudinal Swedish cohort study.

This study is based on a total cohort (N = 192) of people born in 1902 and 1903 and living in southern Sweden. Subjects were assessed at baseline when 67 years of age and on eight further occasions over 34 years or until death. The participation rate in the nine examinations ranged from 78-100%. Interviews, psychological tests, and medical examinations were used as well as information on medical diagnoses from primary health care records and hospital records. The cumulative probability for the development of clinical depression during the follow-up was 8% and for anxiety 6%. The incidence rate for depression and for anxiety was highest during the period 67-81 years. Persons with poor financial status were more likely to be diagnosed with depression but no significant risk factor for anxiety was found. Only 14% developed depression and anxiety during the follow-up period, females more often than men. The strongest risk factors for the development of depression were perceived economic problems.