INTRODUCTION: A generally held clinical impression is that patients with psychological Distress (PD, e.g., Depression, Anxiety, Bi‐Polar Disorder) are likely to have poorer treatment outcomes. The literature provides some support for this impression, but the generalizability across patient cohorts and evidence for a causal link between PD and outcome remain controversial.

METHODS: Patients with lumbar intervertebral disc herniations (IDH) were studied. Patients with MCS scores <= 35 were defined as having PD and, otherwise, were classified as not distressed (Non‐PD). Longitudinal regression models including baseline covariates were used to control for confounding when evaluating patients' Bodily Pain (BP), Physical Function (PF) and Oswestry Disability Index (ODI) outcomes.

RESULTS: The SPORT IDH cohort included 1190 patients: 66% underwent surgery, and 22% reported being depressed at baseline. Change from baseline in PF outcome at 1‐ and 2‐year follow‐up for surgical and non‐operative PD and Non‐PD patients at baseline are summarized below.

Surgical patients demonstrated greater average improvement than non‐operative patients for all three outcomes, p<.0001. However, PD patients treated non‐operatively demonstrated less improvement than Non‐PD patients. In contrast, differences in outcomes in patients with and without PD who underwent surgical intervention were neither statistically significant nor clinically relevant.

DISCUSSION: In this IDH patient cohort, surgical outcomes were unrelated to baseline PD, but, for patients treated non‐operatively, the average amount of improvement from baseline for PD patients was not as good as for non‐PD patients. These results are consistent with the notion that patient non‐compliance – mediated by PD – may be a more reasonable explanation for reduced treatment efficacy when treatment requires greater patient participation.