In a large meta-analysis of pooled data from more than 16,000 patients there were no differences between the individual agents within the SSRI class of antidepressants, or between the individual agents within the SNRI class of antidepressants.1 Although higher doses of SSRIs achieved greater responses, there was no effect of dose with SNRIs.1
From a meta-analysis of 58 studies, a univariable analysis found no correlation between benzodiazepine dosage and change from baseline in Hamilton Anxiety rating scale (HAM-A) score in patients with GAD.2
In an analysis of pooled data from 5 fixed-dose randomized controlled trials in patients with GAD, for overall symptoms, the improvement in HAM-A score increased from placebo up to a dose of 450 mg/day with a reduced effect at 600 mg/day.3 The effect of pregabalin on psychic anxiety symptoms peaked at 400 mg/day, whereas the effect on somatic symptoms continued to increase up to the maximum dose of 600 mg/day.3
In a meta-analysis of 3 randomized controlled trials, mean change from baseline in HAM-A score was consistently greater with quetiapine monotherapy vs placebo at all doses studies, while response and remission rates showed superiority with quetiapine vs placebo only at the 50 mg/day and 150 mg/day dose levels (but not the 300 mg/day dose level).4 The pooled number needed to treat for response with quetiapine 50 mg/day or 150 mg/day was 8.4.4