The research was carried out by an independent group of academic researchers at the University of Toronto who had no direct affiliation with the sponsor. The project was, however, sponsored by Wyeth-Ayerst Canada, but the investigators retained the right to publish results regardless of findings.
A comprehensive literature search was undertaken to identify all published papers on the treatment of depression with the drugs included in the analysis. MEDLINE, EMBASE/ Excerpta Medica and International Pharmaceutical Abstracts were searched for studies published from 1984, when SSRIs were introduced, to the end of 1995. Bibliographies, review papers, meta-analyses and economic evaluations published from 1980 were also searched for SSRIs and TCAs.
To minimize bias, only randomized, double-blind, comparative trials were used to determine clinical efficacy. For discontinuation rates, controlled trials were used, but blinding was not required. Abstracts were excluded along with papers presented at scientific meetings and symposia. Canadian Drugs of interest were venlafaxine, fluoxetine, fluvoxamine, paroxetine, sertraline, amitriptyline, imipramine, desipramine and nortriptyline. Drugs must have been given orally in therapeutic doses for four to eight weeks after a washout period of seven to 14 days.