14.1 : 精神病と抗精神病薬: 概要

Psychosis is a mental disorder characterized by abnormal thinking and perceptions.

It can manifest in various forms, such as mood disorders, dementia, delirium with psychotic features, substance-induced psychosis, brief psychotic disorder, delusional disorder, schizoaffective disorder, and schizophrenia.

Schizophrenia, affecting about 1% of the global population, is the most prevalent psychotic disorder.

In schizophrenia, patients display positive symptoms like hallucinations, delusions, incoherent speech, disorganized or agitated behavior, and negative symptoms like anhedonia, apathy, and alogia. Additionally, cognitive defects may also be observed.

Antipsychotic drugs alleviate psychotic symptoms by blocking dopamine receptors in the brain.

First-generation antipsychotics act at D₂ receptors, while second-generation drugs also antagonize the 5HT_2A receptor.

The goal of antipsychotic treatment is to ease positive symptoms while improving negative symptoms and cognitive dysfunction.

Long-term antipsychotic therapy is vital for chronic disorders like delusional or schizoaffective disorders, schizophrenia, and Parkinson's disease psychosis.