Based on a behavioral medicine perspective, modern recommendations for physical therapists treating patients with spinal pain include performing a trustworthy physical examination, conveying the message that back pain is benign, and stressing that activity is a key to recovery. However, little evidence is available on how patients perceive these biopsychosocial messages and how patients' perceptions of these messages relate to their recovery. The aim of this study was to explore the relationships between perceptions of treatment delivery that are related to an evidence-based approach and psychological factors, treatment outcome, and treatment satisfaction. A cohort study with 3 measurement points was conducted. Data on 281 participants were collected. High catastrophizing and lower mood in the participants were correlated to "not perceiving the biopsychosocial message" measured at 6 weeks after treatment start. Participants who did not perceive the biopsychosocial message were at higher risk for disability and had lower treatment satisfaction 6 months after treatment start even when controlling for pretreatment pain intensity. "Not perceiving the biopsychosocial message" was not a mediator for treatment outcome and treatment satisfaction. Physical therapists' treatment orientations or attitudes were not related to the perception of the message by the patients. There was no measure of actual practice behavior. Maladaptive cognitions and negative emotions appear to affect the way information provided during treatment is perceived by patients. The way information is perceived by patients influences treatment outcome and treatment satisfaction. Physical therapists are advised to check that patients with higher levels of catastrophizing and lower mood are correctly perceiving and interpreting a biopsychosocial message.