Trajectories of depressive symptoms following breast cancer diagnosis

Abstract

Background: This longitudinal study sought to identify groups of breast cancer survivors exhibiting distinct trajectories of depressive symptoms up to 24 months following diagnosis, and to describe characteristics associated with these trajectories.

Methods: A total of 653 women completed baseline questionnaires within 8 months of breast cancer diagnosis on patient characteristics, symptoms, and psychosocial variables. Depressive symptoms were assessed at baseline and 6, 12, and 18 months after baseline. Chart reviews provided cancer and treatment-related data. Finite mixture modeling identified trajectories of depressive symptoms measured with the Beck Depression Inventory (BDI).

Results: Six distinct trajectories were identified. Just over half of the sample had consistently very low (3.8%) or low (47.3%) BDI scores well below the traditional BDI cutoff point of 10 thought to be indicative of clinically significant depression; 29.2% had consistently borderline scores; 11.3% had initially high scores that declined over time, but remained above the cutoff point; 7.2% showed increased BDI over time; and a small but unique group (1.1%) reported chronically high scores above 25. Women in groups with lower depressive symptom levels were older, had less rigorous chemotherapy, fewer physical symptoms (fatigue and pain), and lower levels of illness intrusiveness.

Conclusions: Approximately 20% of women had levels of depressive symptoms indicative of clinical depression that were maintained 2 years postdiagnosis. Factors related to trajectory membership such as illness intrusiveness, social support, fatigue, pain, and vasomotor symptoms suggest targets for possible intervention.

Impact: Results demonstrate the heterogeneity of depressive symptoms following breast cancer and the need for continued screening posttreatment.

Figure 1

Predicted (dashed lines) and observed (solid lines) levels of depressive symptoms for each trajectory group by months since diagnosis. Scores of 10 and above are indicative of clinically significant depression. Percentages refer to the percent of participants in each trajectory group.