(1) To cross-sectionally and longitudinally investigate relationships between the availability and adequacy of both close personal attachment and interactional support, and psychiatric morbidity in a sample of early stage breast cancer patients participating in a 6-week psychoeducational intervention. (2) To address the question of directionality in these longitudinal relationships. (3) To investigate the effects of the intervention on levels of social support.

Eighty-nine women were enrolled in the study, and randomly assigned to either the treatment or control condition. They were evaluated with the Interview Schedule for Social Interaction (ISSI), the Beck Depression Inventory (BDI), the Global Severity Index (GSI) of the Symptom Checklist (SCL) –90-R, and the Structured Clinical Interview for DSM-III-R (SCID) at three time periods: baseline (pre-intervention), 1 year post-intervention and 2 years post-intervention. Relationships between social support and the psychiatric measures were evaluated both cross-sectionally and longitudinally.

Cross-sectionally, there were strong associations at each time period between being diagnosed with a DSM-III-R Axis I disorder and having less adequate perceived social support from both close relationships and more distant social ties. Initial levels of psychiatric symptoms on the BDI and GSI were better predictors of later social support than initial social support variables were of later psychiatric symptoms. Participation in the group intervention did not result in changes in social support at 1 or 2 years post-intervention.

Cross-sectionally, there was a strong relationship between social support and psychiatric morbidity in these patients with early-stage breast cancer. Longitudinally, it appeared that although social support influenced psychiatric symptomatology somewhat, the influence of psychiatric symptoms on social support was greater. This illustrates the importance of both working to bolster social support and dealing with psychiatric symptomatology in this population. Copyright © 2002 John Wiley & Sons, Ltd.