F20-F29: Schizophrenia, schizotypal and delusional disorders

F22: Persistent delusional disorders

Persistent Delusional Disorders are a group of mental health conditions defined by prolonged and consistent delusions -- false beliefs that persist even in the face of conflicting evidence. These disorders can manifest in a variety of ways. For example, a patient may hold irrational fears about being persecuted (persecutory type), may believe they're suffering from a disease without medical evidence (somatic type), or may have other groundless beliefs entrenched in their thinking patterns. The cause of Persistent Delusional Disorders is not fully known, but factors like genetic predisposition, traumatic experiences, and stressful life events may play a role. The main symptom is the presence of one or more delusions that persist for a month or more. These delusions can cause significant distress or impairment in social or occupational functioning. The course of the disease usually involves long periods of stability with gradual progression.