Objective To present a visual clinical decision support tool to help personalize first-line antidepressant pharmacotherapy for adults with major depressive disorder (DCD) in a Canadian setting. Information sources A literature search was conducted using Google Scholar, PubMed, the Cochrane Database of Systematic Reviews and Trip Pro using the MeSH headings in English depression, antidepressive agents, primary care, practice patterns, medication adherence and decision making, shared. Main message Major depressive disorder affects approximately 4.7% of Canadians each year and is frequently observed and diagnosed in primary care. Untreated depression is linked to a lower quality of life, an increased risk of suicide, as well as a deterioration in physical health when depression occurs simultaneously with other chronic health problems. In a network meta-analysis, antidepressant drugs (such as selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, bupropion, and vortioxetine) reduced symptoms of depression by 50% or more. depression versus placebo in the acute treatment of adults with moderate to severe DCD. Poor adherence to treatment and high rates of discontinuation limit successful treatment of DCD. Factors such as strong therapeutic alliances between patients and prescribers, collaborative care, patient education and sustained self-management have been shown to increase treatment adherence. The most recent CANMAT (Canadian Network for Mood and Anxiety Treatments) depression treatment guidelines, published in 2016, offer 15 different first-line antidepressant options for the treatment of DCD. Evidence-based decision aids are needed to personalize antidepressant treatment for patients diagnosed with DCD. Conclusion Recent studies of antidepressants have indicated that no antidepressant is superior to another in the treatment of patients with DCD. This suggests that it may be possible to improve treatment adherence and success by personalizing antidepressant treatment according to individual patient preferences. The Antidepressant Selection Tool was developed to help prescribers and adult patients engage in shared decision-making to choose a personalized and optimal first-line antidepressant for the treatment of acute DCD.