Background: Most prospective studies on the relationship between sense of coherence (SOC) and mental health have been conducted using subjective health indicators and short-term follow-ups. The objective of this prospective occupational cohort study was to examine whether a strong sense of coherence is a protective factor against psychiatric disorders over a long period of time.
Methods: The study was conducted in a multinational forest industry corporation with domicile in Finland. Participants were 8029 Finnish industrial employees aged 18-65 at baseline (1986). Questionnaire survey data on SOC and other factors were collected at baseline; records of hospital admissions for psychiatric disorders and suicide attempt were derived from the National Hospital Discharge Register while records of deaths due to suicide were derived from the National Death Registry up until 2006.
Results: During the 19-year follow-up, 406 participants with no prior admissions were admitted to hospital for psychiatric disorders (n=351) or suicide attempt (n=25) or committed a suicide (n=30). A strong SOC was associated with about 40% decreased risk of psychiatric disorder. This association was not accounted for by mental health-related baseline characteristics, such as sex, age, marital status, education, occupational status, work environment, risk behaviours or psychological distress. The result was replicated in a sub-cohort of participants who did not report an elevated level of psychological distress at baseline (hazard ratio=0.59, 95% confidence interval from 0.40 to 0.86).
Conclusions: A strong SOC is associated with reduced risk of psychiatric disorders during a long time period.