Introduction nce viewed as rare so as not to warrant a separate classification, in recent years paranoid disorder has emerged as a focus of clinical research and treat- ment innovation. Growing literature has revitalized the ef- forts to understand, define, characterize and treat this disor- der. However despite these advances, clinicians are relatively ill-informed about this disorder and many may have only seen an occasional case. This is so as persons with this dis- order don't regard themselves as mentally ill and actively oppose psychiatric referral, experience little impairment and in the infrequent psychiatric encounter may get labeled with schizophrenia or mood disorder (Manschrek, 2000). The present review tries to update on historical aspects, current nosology and validity of the concept, and treatment strategies for the delusional disorder within the constraints of the search strategies employed. The search strategies for