OBJECTIVES: Shared decision-making (SDM) utilization has increased in the recent years with a noted increase in the effectiveness of treatment. Many studies confirmed that decision aids (DAs) improve participation in SDM more than standard counseling. This study is aimed to evaluate a DA that support depressed patients in decision-making regarding using antidepressant treatment and improve the quality of decision by increasing patients’ involvement in SDM METHODS: A pilot randomized controlled double-blinded study was conducted at Al-Amal Complex for Mental Health in Riyadh City, Saudi Arabia between March and May, 2014. The impact of the developed DA on patients' involvement was assessed using observing patient involvement in decision-making (OPTION Scale) in a counseling session by a trained clinical pharmacist and an assistant researcher and the data are analyzed using the Statistical Package for Social Sciences version 17 RESULTS: The impact of the DA was assessed by interviewing 44 depressed participants in SDM sessions. Based on OPTION scale, a 13% difference was noted between the controlled group and intervention group with a result of 66% and 79% of involvement, respectively. There is a significant improvement in the involvement of patient in the intervention group (p<0.05) in comparison with the controlled group. However, there is a statistically significant difference at level (p<0.01) in the elicitation of the patient's preferred level of involvement in decision-making in favor of intervention group CONCLUSIONS: The DA showed an evidence of improving patients’ participation in SDM process which was assessed by OPTION-Scale. Further research is needed to evaluate the DA’s true effectiveness and its impact on long-term outcomes