Located in a community mental health center, the first decision support center in psychiatry used peer support and an Internet-based software program, CommonGround, to assist consumers in decisional uncertainty about psychiatric medication use and to foster shared decision making between the consumer and prescriber. This study examined the impact of the decision support center on the consumer-doctor interaction in the medication consultation. A pretest/posttest design assigned consumers to either an experimental or control group for 4 months. The Measure of Patient-Centered Communication (MPCC) (Brown, Stewart, McCracken, McWhinney, & Levenstein, 1986) was used to evaluate the medication consultation. The Patient Perception of Patient-Centeredness Questionnaire (PPPC) (Stewart, Meredith, Ryan, & Brown, 2004) was used to evaluate the consumer's and prescriber's perceptions of the consultation. A one-way multivariate analysis of covariance was not significant for the combined dependent variable of the measures at Time 2, while controlling for the measures at Time 1. When the CommonGround report was referenced in the experimental group, post hoc analyses revealed significant differences (t[41] = 4.14, p =.001) in the PPCC-consumer score. This study provides provisional evidence of the effectiveness of a shared decision-making intervention. The clinical potential of a program that assists mental health consumers in communicating decisional uncertainty and developing shared decisions concerning medication use is worthy of further study.