Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom severity
[51] Systematic review	1056 people 4 RCTs in this analysis	Non-response rate 8 to 28 weeks 277/606 (46%) with antidepressants (imipramine, paroxetine, and venlafaxine) 280/449 (62%) with placebo	RR of not responding 0.70 95% CI 0.62 to 0.79 NNT 6 95% CI 5 to 9	Small effect size	antidepressants
[53] RCT	230 people In review [51]	Proportion of people with participant-assessed global improvement 8 weeks 73% with imipramine 67% with trazodone 66% with diazepam 39% with placebo	P <0.026 for any drug v placebo Results not analysed by intention to treat	Effect size not calculated	antidepressants
[52] Systematic review	1342 people 3 RCTs in this analysis	Proportion of people who relapsed after responding to treatment 6 months 93/664 (14%) with continuation of antidepressants 304/678 (45%) with placebo	OR 0.2 95% CI 0.15 to 0.26 NNT 3 95% CI 2.86 to 3.85	Moderate effect size	antidepressants