Nineteen studies (n=834) were included in the review: 17 RCTs (12 parallel-group design and 5 crossover design) and 2 CCTs.
The median score for methodological quality in the included studies was 4 (range: 2 to 7). When considering scores above 6 as high, only 2 studies were considered to have high quality; the most common shortcoming was blinding and allocation concealment.
Relaxation.
Two studies of very small sample size presented data with inconsistent results: comparison with waiting list showed a significant difference while comparison with placebo (attention) did not.
Biofeedback (6 studies).
One study compared biofeedback with placebo, two compared the additional effect of biofeedback on relaxation, or relaxation plus behavioural management, two compared biofeedback with waiting list, and one compared clinical-based thermal biofeedback with home-based thermal biofeedback. No statistically significant differences were found
CBT (2 studies).
One study compared cognitive coping with placebo (attention) and one compared the effect of behavioural management of pain added to thermal biofeedback treatment. No significant differences were found post-treatment, but inconsistent results were found at 3 to 4 months’ follow-up.
Combined behavioural treatments (6 studies).
Two studies compared relaxation combined with thermal biofeedback to waiting list. The pooled RR showed a significant post-treatment difference in favour of the intervention (RR 4.20, 95% CI: 1.79, 9.83). One study comparing relaxation plus CBT with waiting list showed no significant difference. One study comparing home-based relaxation plus behavioural therapies with placebo showed a significant difference favouring the intervention (RR 2.78, 95% CI: 1.31, 5.90), but no significant difference between clinical-based relaxation plus CBT and home-based relaxation plus CBT, or between clinic-based relaxation plus CBT and placebo. One study compared relaxation and stress management with metoprolol or cephalic vasomotor feedback plus stress management and found no significant difference between groups. Two studies compared relaxation plus CBT plus biofeedback with waiting list, and the effect size post-treatment was significant in favour of the combined intervention (RR 2.84, 95% CI: 1.04, 7.77).
Other non-pharmacologic prophylactic treatments (7 studies).
One study evaluated instruction to follow guidelines towards improving sleep hygiene and found significantly lower headache frequency compared with the non-instruction group at 3 months’ follow-up (RR 0.38, 95% CI: 0.15, 0.96) and 6 months’ follow-up (RR 0.33, 95% CI: 0.12, 0.93). No difference was found in the use of red- or blue-tinted glasses. One study showed that the exclusion of foods with vasoactive amines in a diet rich in fibre did not improve headache. Two studies showed that oligoantigenic diets (diets that exclude milk, eggs, food additives and vasoactive amine-containing foods) are more effective than placebo (RR 0.23, 95% CI: 0.12, 0.47; RR 6.11, 95% CI: 2.12, 17.5). One high-quality study compared the use of fish oil with placebo (olive oil) and found no significant differences. Another small high-quality study compared acupuncture with placebo and found significantly lower headache in the intervention group (SMD -7.31, 95% CI: -9.84, -4.78).