OBJECTIVES: Increasing rates of disability pension (DP), particularly owing to mental diagnoses, have been observed among young adults in Organisation for Economic Co-operation and Development (OECD) countries. There is a lack of knowledge about the health prognosis in this group. The aim of this study was to investigate whether DP in young adulthood owing to specific mental diagnoses or somatic diagnoses predicts suicidal behaviour and all-cause mortality.

DESIGN: A nationwide prospective cohort study.

SETTING: A register study of all young adults who in 2005 were 19-23 years old and lived in Sweden. Registers held by the National Board of Health and Welfare, Statistics Sweden and the National Social Insurance Agency were used.

PARTICIPANTS: 525 276 young adults. Those who in 2005 had DP with mental diagnoses (n=8070) or somatic diagnoses (n=3975) were compared to all the other young adults in the same age group (n=513 231).

OUTCOME MEASURES: HRs for suicide attempt, suicide and all-cause mortality in 2006-2010 were calculated by Cox proportionate hazard regression models, adjusted for sex, country of birth, parental education and parental and previous own suicidal behaviour.

RESULTS: The adjusted HR for suicide attempt was 3.32 (95% CI 2.98 to 3.69) among those on DP with mental diagnoses and 1.78 (95% CI 1.41 to 2.26) among those on DP with somatic diagnoses. For the specific mental diagnoses, the unadjusted HRs ranged between 2.42 (mental retardation) and 22.94 (personality disorders), while the adjusted HRs ranged between 2.03 (mental retardation) and 6.00 (bipolar disorder). There was an increased risk of mortality for young adults on DP in general, but only those with mental DP diagnoses had a significantly elevated HR of completed suicide with an adjusted HR of 3.92 (95% CI 2.83 to 5.43).