While depression generally improves after bariatric surgery, less is known regarding heterogeneity in long-term symptom change. Given that depressive symptoms have been associated with weight change following bariatric surgery, identifying and characterizing subgroups with more severe depressive symptoms may have prognostic utility for understanding post-surgical weight loss. This study sought to characterize patterns of change in depressive symptoms and evaluate associations with weight loss in the seven years following bariatric surgery.

Participants were 2308 patients who underwent bariatric surgery as part of the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) study. Depressive symptoms (measured by the Beck Depression Inventory) and weight were assessed annually following surgery.

A group-based trajectory model identified six subgroups that evidenced distinct patterns of change in depressive symptoms, with the majority (87.0%) exhibiting stable low to average levels. Generalized linear mixed models indicated trajectory groups differed in percent total weight loss (%TWL), with trajectories characterized by initial decreases in depressive symptoms over the first two years (5.2% of participants) experiencing the highest %TWL (20.7% vs. 14.9–18.4% in the other trajectories at 7 years).

Findings demonstrate meaningful heterogeneity in the pattern of changes in depressive symptoms after surgery. While most patients experience relatively low stable levels of depressive symptoms, those who have initial symptom improvement demonstrate the greatest magnitude of weight loss. Further research is necessary to explore the directionality of this association and the time-varying mechanisms by which depression and weight may mutually influence each other.