1 Partial Psychosis Domina Petric, MD ABSTRACT Partial psychosis is a delusional disorder characterized by at least one month of delusions without other psychotic symptoms. Ongoing behavior can be influenced by delusional content, but impairments in psychosocial functioning are less severe than those seen in other psychotic disorders, and behavior is not obviously bizarre. Delusions are defended in an intelligent way and person can still function in the reality. One part of individual´s psyche is in accord with reality, but other part has well-organized delusions that are fixed and continuous. INTRODUCTION In his textbook from 1838, Esquirol made the first comprehensive psychopathological description of paranoia, which he labeled partial psychosis. This was a condition with encapsulated, well organized, and persistent delusions. These are defended with a great deal of emotions and sharp argument. The individual appears quite convincing, especially because he or she otherwise behaves rationally. The intellectual capacity is used to achieve defined goals according to the delusional content. This condition is difficult to uncover because of dissimulation and adaptation 1 . PARTIAL PSYCHOSIS Karl Jaspers described delusions as abnormal beliefs held with conviction, impervious to experiential evidence or counter-arguments, and often bizarre 2 . According to DSM-5, schizophrenia spectrum and other psychotic disorders are defined by abnormalities in one or more of the following five domains: delusions, hallucinations, disorganized thinking, grossly disorganized or abnormal motor behavior, and negative symptoms 3 . The disorders are organized along a gradient of psychopathology with delusional disorder in the ˝benign˝ end as a condition limited to one domain of psychosis only, namely delusions 1 . Delusional disorder is characterized by at least 1 month of delusions without other psychotic symptoms. In patients with delusional disorder, ongoing behavior can be influenced by delusional content, but