Life stress and the symptoms of major depression.

Life stress has been found to be associated with onset of depression and with greater severity of depressive symptoms. It is unclear, though, if life stress is related to particular classes or specific symptoms in depression. The association between severe life events and depressive symptoms was tested in 59 individuals diagnosed by Research Diagnostic Criteria with endogenous primary nonpsychotic major depression. As predicted, life stress was associated principally with cognitive-affective symptoms, not somatic symptoms. There also was a consistent association across different assessment methods between severe events and suicidal ideation. Finally, associations held specifically for severe events occurring before onset, not for severe events occurring after onset. Symptom variation in major depression is related specifically to severe stressors before onset and includes primarily cognitive-affective types of symptoms. There is an especially pronounced association of prior severe stress with suicidal ideation. The implications of stress-symptom associations are addressed for enlarging understanding of symptom heterogeneity and subtype distinctions in major depression.