Psychological Response In Spinal Manipulation (PRISM): a systematic review of psychological outcomes in randomised controlled trials

BACKGROUND:
The most important risk factors for back and neck pain are psychosocial. Nevertheless, systematic reviews of spinal manipulation have concentrated on pain and spine related disability, and ignored psychological outcomes.
OBJECTIVE:
To assess whether spinal manipulation was effective in improving psychological outcome.
DESIGN:
Systematic review of randomised controlled trials (RCTs).
METHODS:
RCTs were identified by searching Medline, CINAHL, Embase, CENTRAL, AMED, PsycINFO until November 2005. Trials reporting psychological outcomes including the mental health components of generic outcomes were extracted, and combined where appropriate in meta-analyses.
RESULTS:
One hundred and twenty nine RCTs of spinal manipulation were identified; 12 had adequately reported psychological outcomes. Six trials with a verbal intervention comparator were combined in a meta-analysis, and found a mean benefit from spinal manipulation equivalent to 0.34 of the population standard deviation (S.D.) [95% confidence interval (CI) 0.23-0.45] at 1-5 months; 0.27 of the S.D. [95% CI 0.14-0.40] at 6-12 months. Eight trials with a physical treatment comparator were combined in a meta-analysis and found a mean benefit of 0.13 of the S.D. [95% CI 0.01-0.24] in favour of manipulation at 1-5 months; 0.11 of the S.D. [95% CI -0.02 to 0.25] at 6-12 months.
CONCLUSIONS:
There was some evidence that spinal manipulation improved psychological outcomes compared with verbal interventions.