Background Suicide mortality is high among the unemployed, but the role of causation and selection models in producing employment status differences remains to be understood. This study analyses the association between unemployment and suicide during different levels of national unemployment adjusting for several factors that might explain or mediate the relationship.

Methods The data comprised annual population-register and death-register information on 25–64-year-old Finns at the beginning of each year in the period 1988–2003; thus, forming 16 separate follow-up cohorts. Experience of unemployment was measured at baseline and during the previous year for each cohort. Suicide was followed for 12 months after each baseline giving a total of 7388 suicides.

Results Overall, age-adjusted suicide mortality was two to three times higher among the unstably employed and almost fourfold among the long-term unemployed. Adjustment for social class and living arrangements had small effect on the HRs, but adjustment for household income per consumption unit decreased the differences by 13% and 31% among the long-term unemployed women and men, respectively. When the national unemployment level was high, excess suicide mortality among the unstably employed was lower than during low unemployment when those becoming unemployed might be more selected. No such differences were found among the long-term unemployed.

Conclusion Long-term unemployment seems to have causal effects on suicide, which may be partly mediated by low income. As the effect of unstable employment is lower during the recessionary stage of the economic cycle some part of the excess suicide among the unstably employed is likely to be attributable to selection into unemployment.