Drug Repurposing Is a New Opportunity for Developing Drugsagainst Neuropsychiatric Disorders

Better the drugs you know than the drugs you do not know. Drug repurposing is a promising, fast, and cost effective method thatcan overcome traditional de novo drug discovery and development challenges of targeting neuropsychiatric and other disorders.Drug discovery and development targeting neuropsychiatric disorders are complicated because of the limitations in understandingpathophysiological phenomena. In addition, traditional de novo drug discovery and development are risky, expensive, and time-consuming processes. One alternative approach, drug repurposing, has emerged taking advantage of off-target effects of theexisting drugs. In order to identify new opportunities for the existing drugs, it is essential for us to understand the mechanismsof action of drugs, both biologically and pharmacologically. By doingthis,drugrepurposingwouldbeamoreeffectivemethodtodevelop drugs against neuropsychiatric and other disorders. Here, we review the difficulties in drug discovery and development inneuropsychiatric disorders and the extent and perspectives of drug repurposing.