The impact of mood disorders on cognitive function in post-menopausal women undergoing treatment for early-stage breast cancer

Purpose. Many post-menopausal women who are treated for early-stage breast cancer report experiencing cognitive difficulties following adjuvant chemotherapy. However, the generalizability of the results of a number of studies that have attempted to document the association between adjuvant chemotherapy and cognitive dysfunction has been limited due to inconsistencies in the investigative methods used, thus introducing the possibility that other factors are contributing to reports of cognitive problems. The current study examines the possibility that a history of mood disorders in post-menopausal breast cancer patients predisposes them to cognitive difficulties following adjuvant treatment. Methods. Sixty-five postmenopausal women with non-metastatic breast cancer were administered the SCID-I before adjuvant therapy (Time 1) to determine psychiatric status. Thirty women were found to have a history of mood disorder, while thirty-one women were found to have no history of mood disorder. Participants were administered neuropsychological tests before adjuvant therapy (Time 1), six months after treatment (Time 2), and at a final six-month follow-up (Time 3). Cognitive domains measured included motor, language, attention/concentration/working memory, visuospatial, memory (verbal and visual). Results. Group comparisons found significant differences in several domains at Time 1 (attention) and Time 2 (visual spatial and visual memory), but in each case the mood disorder group means were higher than the group means of the non-mood disorder group. No significant results were found at Time 3. Conclusion. In postmenopausal women, a history of mood disorder was associated with higher performance in selected cognitive domains. Reasons for these paradoxical results are explored and suggestions for future research are proposed.