Factors influencing adherence to antidepressants in Thai depressed patients

This study aimed at examining factors influencing adherence to antidepressants treatment in Thai depressed patients focusing on socioeconomic characteristics, treatment characteristics and attitudes towards antidepressant treatment and physicians. The study design was a descriptive cross-sectional survey by using questionnaires. The study samples were Thai depressed patients diagnosed of depression by psychiatrists and admitted as outpatients at psychiatric clinic of King Chulalongkorn Memorial Hospital during April to December 2007. The study samples were 217 patients. Most of the patients had high adherence using both Likert scale measurement (mean ± SD; 22.63 ± 3.25) and visual analog scale (mean ± SD; 87.68 ± 16.81). The study showed that 80.6 % of patients experienced side effects from antidepressants. Most common side effects were dry mouth, somnolence, fatigue, insomnia and weight gain, respectively. The main reasons for antidepressant nonadherence were medicine forgotten, feeling better, adverse events, fear of antidepressant dependence, respectively. Most of the patients had favorable beliefs about antidepressants (mean ± SD of score; 3.69 ± 0.48) and had higher favorable beliefs about physicians (mean ± SD of score; 4.06 ± 0.54). Patients with low income, increased impact of side effects, forgetting of drugs and unfavorable attitudes towards antidepressants were related to nonadherence to treatment. Multiple regression of adherence to antidepressants found impact of side effects, medicine forgotten and two aspects of attitudes towards medications; i.e., efficacy of antidepressants and taking less when feeling better, significantly predicted the adherence to antidepressant treatment and accounted for 12.6 % of the coefficient of determination. Thus, adherence to antidepressants treatment was improved by increasing favorable attitudes towards medications, enhancing awareness to take medications and decreasing impact of antidepressant side effects.