Patients who suffer from depression and anxiety disorders comorbidity take a longer time to respond to medication. They also have a higher relapse risk than patients with only one disorder. Consequently, Patients with comorbidity are given a longer-term treatment than other patients. The tolerability and the easiness of use of those medications are important factors in the treatment of comorbidity because they determine the continuity of usage. Elderly patients have a high chance of taking other medication and might have altered drug metabolism. Therefore, the needs of this group of patients should be considered when formulating or prescribing comorbidity medications to ensure the tolerability and safety of these medications.