Toxic psychosis

Facts box Toxic psychosis is characterized by the presence of psychotic symptoms usually associated with acutely impaired cognitive functions. A number of centrally active prescription drugs taken in excessive amount can cause neurotoxicity. Clinical manifestations include delirium with features of altered consciousness, impairment of general cognitive functions, acute onset, fluctuating course, nocturnal worsening, and presence of delusions, hallucinations, and thought disorder. It is sometimes difficult to differentiate between toxic psychosis and primary psychiatric conditions. General risk factors include older age, underlying dementia, and severe physical illness. Several classes of drugs have been implicated. Pathogenesis of toxic psychosis is poorly understood. However, current knowledge is that there is dysfunction of a number of neurotransmitters such as acetylcholine, dopamine, GABA, and glutamate. Management includes the identification and treatment of the underlying cause, which is often multifactorial. Common clinical situation: clinicians should be able to correctly identify this state to reduce mortality. Current research is flawed by methodological issues. Future research should include a large number of patients, use standardized measurements, study individual drugs, and control confounders. Introduction A number of terms have been used in literature to describe psychosis associated with acutely impaired cognitive functions. These include toxic psychosis, acute brain syndrome, acute organic psychosis, acute confusional state, ICU psychosis, metabolic encephalopathy, toxic confusional state, and delirium. The multiple terms used to denote this state lead to confusion both in clinical and research practice. Therefore, the more recent psychiatric diagnostic and classification systems (DSM-IV and ICD-10) opted to use the term “delirium”.