The designs of the included studies were unclear. A total of 49 studies were included: 33 of pharmacological treatments and 16 of non-pharmacological treatments.
All results are presented as the number of independent samples contributing to the pooled effect size (n) and the pooled effect size (ES). The heterogeneity test results were not reported.
Pharmacological treatments.
Antidepressants: the ES was 0.37 (n=11, p<0.05) for physical status, 0.49 (n=12, p<0.05) for FMS symptoms, 0.22 (n=4, p>0.05) for psychological status, and 0.15 (n=4, p>0.05) for daily functioning.
Muscle relaxants: the ES was 0.89 (n=7, p<0.05) for physical status, 0.47 (n=7, p<0.05) for FMS symptoms, 0.26 (n=3, p<0.05) for psychological status, and 0.24 (n=1, p>0.05) for daily functioning.
Non-steroidal anti-inflammatory drugs: the ES was 0.08 (n=3, p>0.05) for physical status, 0.06 (n=3, p>0.05) for FMS symptoms, 0.49 (n=1, p>0.05) for psychological status, and -0.25 (n=1, p>0.05) for daily functioning.
Other: physical status: the ES was 0.73 (n=17, p<0.05) for physical status, 0.50 (n=17, p<0.05) for FMS symptoms, 0.68 (n=10, p<0.05) for psychological status, and 0.15 (n=2, p>0.05) for daily functioning.
Non-pharmacological treatments.
Physically-based: the ES was 0.71 (n=7, p<0.05) for physical status, 0.56 (n=8, p<0.05) for FMS symptoms, 0.38 (n=5, p<0.05) for psychological status, and 0.29 (n=3, p>0.05) for daily functioning.
Psychologically-based: the ES was 0.60 (n=6, p<0.05) for physical status, 0.63 (n=6, p<0.05) for FMS symptoms; 0.60 (n=5, p<0.05) for psychological status, and 0.38 (n=3, p<0.05) for daily functioning.
Combination: the ES was 0.55 (n=4, p<0.05) for physical status, 0.63 (n=3, p<0.05) for FMS symptoms; 0.56 (n=3, p<0.05) for psychological status, and 0.49 (n=3, p<0.05) for daily functioning.