The impact of recent undesirable life events on psychiatric disorders in childhood and adolescence.

The timing and number of recent stressful life events occurring in the year before onset of emotional or behavioural disorder was examined in a consecutive sample of children. Overall, events increase the relative risk of psychiatric disorder by 3-6 times. Events occur throughout the 12 months, but tend to cluster in the 16 weeks nearest onset of symptoms. The number of events influences the onset of disorder: cases with multiple events are more likely to have an event within 16 weeks of onset; cases with single events are more likely to have the event 36-52 weeks before onset. Cases whose onset occurs within 4 weeks of an event may have experienced single or multiple events. The results support the concept of additivity of recent stressful events in some cases of emotional and behavioural disorders in childhood.