Chronic back pain (CBP) is a major global health problem, while its treatment is hampered by a lack of efficacy and restricted safety profile of common frontline therapies. The present trial aims to determine whether a 3-week open-label placebo treatment reduces pain intensity and subjective and objective functional disability in patients with CBP. This randomized controlled trial, following a pretest–posttest design, enrolled 127 patients with CBP (pain duration .12 weeks) from the Back Pain Center, Neurology, University Hospital Essen, Germany. Patients randomized to the open-label placebo group received a 3-week open-label placebo treatment. Patients in the treatment as usual (TAU) group received no intervention. Both groups continued TAU. Primary outcome was the change in pain intensity. Secondary outcomes included patient-reported functional disability and objective measures of spine mobility as well as depression, anxiety, and stress. One hundred twenty two patients with CBP were randomized to the open-label placebo group (N 5 63) or TAU group (N 5 59). With regard to the study protocol the primary outcome pain intensity, depicted by the composite VAS score (VAScomp) (t(104.3)=-2.649, p<.001) decreased in the OLP+TAU group compared to the TAU group. With respect to functional capacity, as a secondary outcome, the Oswestry Disability Index (ODI) (t(116.470)=2.574, p=.01), showed a decreased functional impairment in the OLP+TAU group. This also applies to the depression subscale of the Depression-Anxiety-Stress-Scale (DASS) (t(99.053)=2.247, p=.02) as an explorative outcome, indicating a decreased depression score. 

Open-label placebo treatment did not affect objective mobility parameters, anxiety and stress. Interestingly, individual pain catastrophizing (at baseline conditions) might modulate the beneficial effect of OLP on objectively measurable motion characteristics. Specifically, an improved movement velocity following the OLP treatment was found only in low pain catastrophizers, which might explain the lack of significant main effect of OLP-treatment on objective measures.Our study demonstrates that a 3-week open-label placebo treatment is safe, well tolerated and reduces pain, disability, and depressive symptoms in CBP. Trial registration: German Clinical Trials Register, DRKS00012712.