OBJECTIVES: The Canadian Psychiatric Association (CPA) treatment guidelines for generalized anxiety disorder (GAD) were developed using evidence-based criteria. CPA recommends: selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) as 1st line; benzodiazepines, bupropion, buspirone, pregabalin, and imipramine as 2nd line; and hyroxyzine, mirtazapine, trazadone as 3rd line treatments including adjunctive olanzapine or risperidone for treatment-resistant patients. A comprehensive quantitative synthesis of guideline-recommended drug therapies for GAD has not been located. The objective of the study was to quantify the rates of clinical outcomes of CPA guideline-recommended pharmacotherapies by line treatment. METHODS: Evidence from randomized clinical trials cited by the CPA and (original research) from meta-analytic evidence were included for review. Pooled analyses, duplicates, inappropriate condition, and studies with non-extractable data were excluded. Response, remission rates, and baseline, endpoint or mean reductions scores of the Hamilton Rating Scale for Anxiety (HAM-A) were extracted. Review Manager-5 software (Cochrane Collaboration 2008), with fixed effects model using inverse variance weighting, was used to pool results. RESULTS: First line: 36 studies included, 21 excluded [pooled-analysis(4) duplicate(14), non-extractable(1), not published(1); inappropriate condition(1)], 2nd line: 67 included, 34 excluded [pooled-analysis(2) duplicate(30) non-extractable(2)], 3rd line: 7 studies included, 0 excluded. Mean HAM-A at baseline for 1st line: 24.8(SD=1.94, N=2594), 2nd line: 25.7(SD=2.08, N=2592), 3rd line: 23.4(SD=3.54, N=274). Mean HAM-A score reductions were: 1st line: -13.48[CI95%-14.33, -12.63, N=1990], 2nd line: -12.19[CI95%-12.38, -12.00, N=2046], 3rd line: -12.31[CI95%-12.96, -11.67, N=238]. Summary remission rates were: 1st line: 39.7%[CI95%35.2-44.1%, N=1502], 2nd line: no pooled results, 3rd line: 35.7%[CI95%23.1-48.2%, N=56]. Summary response rates were 1st line: 67.7%[CI95%64.1-71.4%, N=2311], 2nd line: 54.5%[CI95%48.0-61.1%, N=1409], 3rd line: 54.9%[CI95%39.7-70.2%, N=242]. CONCLUSIONS: Summary results overlapped substantially; no statistical conclusion could be drawn as to which line of therapy was clinically superior.