Background: The provision of clinical pharmacy related services involves not only medication therapy, but decisions about medication selection, dosages, routes and methods of administration, medication therapy monitoring, and the provision of medication-related information and counselling to individual patients. Objective: To evaluate the clinical pharmacist's interventions with a focus on resolving drug related problems (DRPs). Methods: This is a prospective study that was performed in a tertiary mental health hospital in Abha city, Saudi Arabia. The clinical pharmacy team conducted a clinical rotation on a daily basis for rendering clinical pharmacy services. Based on the clinical pharmacist's assessment, the identified DRP's were identified and communicated with other clinicians to concerned patient-centered care and the resulting outcomes were measured. Also, the acceptance rate for the clinical pharmacist ’ s interventions was evaluated. Results: A total of 824 DRPs were identified for 420 cases. The most common DRPs reported were found to be regarding Therapeutic Drug Monitoring (n=345, 41.87%) followed by need for counselling (n=175, 21.24%), drug selection (n=180, 21.84%), over or under dosage (n=87, 10.6%), adverse reactions (n=20, 2.43%), compliance (n=14, 1.7%), and under treatment (n=3, 0.36%). For all the identified DRP's a total of 446 interventions (54.13%) were proposed and accepted by the clinicians. Conclusion: Present study showed that introducing clinical pharmacist within the psychiatry team improves the therapeutic optimization and the clinical pharmacist is a trustworthy team member.