Psychosis is broadly defined as the presence of delusions and hallucinations and can be organic or functional in nature. The former is secondary to an underlying medical condition, such as delirium or dementia, the latter to a psychiatric disorder, such as schizophrenia or bipolar disorder. Functional psychosis is relatively common in the general population, with epidemiological studies estimating its prevalence to be approximately 0.2-0.7%. Prevalence in the elderly increases to 4.8%. The identification and treatment of psychosis is important as it is associated with a 10% lifetime risk of suicide and significant social exclusion. Delays in recognition can ultimately lead to a worse prognosis.