Authored by Jussi Vahtera of the Finnish Institute of Occupational Health in Helsinki, the five-year study focussed on a sample of 16,627 people with undisturbed sleep and 2,572 with disturbed sleep.
An assessment of each person's liability to anxiety was made at the onset. The occurrence of post-onset life events (death or illness in the family, divorce, financial difficulty and violence) and sleep disturbances were measured at follow-up five years later.
According to the results, both liability to anxiety and exposure to negative life events were strongly associated with sleep disturbances.
Among those liable to anxiety, the odds of sleep disturbances were 3.11 times higher for those who had experienced a severe life event within six months than for the others.
Those not liable to anxiety had odds of only 1.13 for sleep disturbances. "This five-year follow-up showed that exposure to severe stressful events can trigger sleep disturbances in people with undisturbed sleep before the event," said Vahtera.