Interaction between demand-control and social support in the occurrence of common mental disorders

OBJECTIVE: To analyze the interaction between the psychosocial aspects of work and the occurrence of common mental disorders among health workers. METHODS: This is a cross-sectional study conducted with a representative sample of workers of the primary health care of five municipalities of the State of Bahia, Brazil, in 2012. The variable of outcome were the common mental disorders evaluated by the SRQ-20, and the variables of exposure were high demand (high psychological demand and low control over the work) and low social support in the workplace. Interaction was checked by the deviation of the additivity of the effects for the factors studied from the calculation of excess risk from interaction, proportion of cases attributed to interaction, and the synergy index. RESULTS: The global prevalence of common mental disorders was 21%. The group of combined exposure has shown higher magnitude (high demand and low social support), reaching 28% when compared to the 17% in the situation of no exposure (low demand and high social support). CONCLUSIONS: The results strengthen the hypothesis of interaction between the factors investigated, directing to the synergy of the effects.