Objectives: Current treatments of oral lichen planus are palliative, not curative. Because psychiatric disorders significantly influence the development and severity of oral lichen planus, the use of psychiatric drug therapy may be an adjunct in treatment. The purpose of this study was to determine the efficacy of drug therapy of psychiatric disorders in oral lichen planus. Study design: Our controlled clinical study consisted of forty-six patients with oral lichen planus and psychiatric disorders who were randomly divided into two groups. Both groups were given topical corticosteroids and the study group received additional psychiatric drug therapy. Patients were monitored for a period of 6 months. Response to treatment was evaluated in each group and was compared with the other group using Mann-Whitney tests. We evaluated the correlation between psychiatric disorders and the recovery of oral lesions using Spearman?s correlation coefficient analysis. Results: Decrease in the size of the lesions was significantly greater in the study group after six months, but this difference was not significant in relationship to the pain experienced and the kind of lesion. Spearman?s correlation coefficient analysis demonstrated that, in the sixth month, there was a significant and direct relationship between recovery from the psychiatric disorders and response to treatment of OLP lesions, particularly as it pertained to the kind of lesion. Conclusion: The present study indicates that the combination of psychiatric drug therapy and routine treatment methods were effective in reducing the size of the lesions, but did not have any significant effect on the symptoms.