Evidence Summaries

A Cochrane review ¹ included 21 studies with a total of 2693 subjects with depression. Seven studies used placebo (n = 771) and 20 used cyclic antidepressants (n = 1765). The typical duration of the studies was 4 to 6 weeks. When alprazolam was compared with placebo for reduction in symptoms all estimates indicated a positive effect for alprazolam. Pooled estimates of efficacy data showed a moderately large continuous mean difference (MD) at the end of trial (-5.34, 95% CI -7.48 to -3.20; 7 studies, n=771). The risk difference (RD) for the dichotomous measure of clinical response (50% improvement) was 0.32 in favour of alprazolam (95% CI 0.22 to 0.42; 3 studies, n=312), with NNT of 3 (95% CI 2 to 5). The RD of all-cause withdrawals did not differ between alprazolam and placebo. When depression severity was measured as a continuum, the effect of alprazolam did not differ statistically or clinically from the effects of any of the conventional antidepressants combined (MD 0.25, 95% CI -0.93 to 1.43; 17 studies, n=1636). However, for dichotomised depression severity, alprazolam had less effect than antidepressants (RR 0.86, 95% CI 0.75 to 0.99; RD -0.11, 95% CI -0.24 to 0.01; NNT 9, 95% CI 4 to 100; 7 studies, n=543). The RD of all-cause withdrawals was -0.04 (95% CI -0.07 to 0.00; 18 studies, n=1873), in favour of alprazolam.

Comment: The quality of the evidence is downgraded by study quality (unclear allocation concealment) and potential publication bias (all studies sponsored by the pharmaceutical company manufacturing alprazolam).

References