BACKGROUND: Adherence to and persistence with antidepressants are often suboptimal. However, little is known about how patient knowledge and outcome expectations may influence antidepressant adherence and persistence.

METHODS: Individuals who had been prescribed their first antidepressant to treat depression in the preceding six months were recruited to an online survey via Facebook. Knowledge, education received and initial outcome expectations were analysed for associations with persistence and adherence.

RESULTS: There were 220 surveys analysed. A total of 117 participants had taken their antidepressant for at least three months, while 25 had never started or stopped after less than three months without their doctor’s involvement. Differences in expectations and various educational messages amongst persistent and non-persistent participants were identified. The instruction "don’t stop it without checking with your doctor" was a significant independent predictor of persistence (OR = 5.9, 95% CI = 1.4-24.5).

At the time of the survey, 82.7% participants were taking an antidepressant and 77.9% were adherent. Significant independent predictors of adherence were a greater age (OR = 1.1, 95% CI = 1.0-1.2), knowledge (OR = 1.6, 95% CI = 1.1-2.3), being informed of common side effects (OR = 5.5, 95% CI = 1.1 29.0) and having discussed ways to solve problems (OR = 3.9, 95% CI = 1.1-14.5).

DISCUSSION: Improving outcome expectations and particular educational messages may increase adherence and persistence. Greater knowledge may help adherence. Further investigation is warranted to investigate whether a focus on these simple educational messages will improve outcomes in patients who commence an antidepressant.