Delusional Disorder 2021

Despite being considered a valid diagnosis, in the last decades there has been a great confusion concerning the terminology used to describe delusional disorder. Furthermore, the clinical utility of the classification according to the content of delusions has been found to be controversial. The aim of the present review is to summarize epidemiological, clinical and treatment outcomes in patients with delusional disorder. The prevalence of delusional disorder is low (0.03%), being higher in emergency departments and in prisons. The basic psychopathological phenomenon is the morbid or patho- logical significance, which differentiates “paranoia delusions” from delusions of schizophrenia or affective delusions. Studies focusing on clinical trajectories of delusional disorder report rates of diagnos- tic stability to be around 80%. Classical authors have defined two main phenotypes potentially useful for the clinicians: 1) Paranoia vera (similar to interpretative delusion) and 2) Paranoia querulans (litigant’s delusion); but the most important controversy remains response to treatment. A recent systematic review reports response rates between 5-50%. No consensus seems to exist with regard to the operational definition of antipsychotic response, a fact that may partly explain heterogeneity in response data. The identification of predictive factors of treatment response may help to improve clini- cal outcomes. Variables potentially moderating response in DD are age, gender, reproductive status, comorbidity, brain structure and genetic variants of dopaminergic receptors and drug metabolizing enzymes. Antipsychotic plasma levels, functional brain changes and hormonal levels are considered mediators of antipsychotics response. Therapeutic adherence in delusional disorder remains one of the major challenges in psychosis.