Definition of Psychosis:

Psychosis is a loss of contact with reality, usually including false beliefs about what is taking place or who one is (delusions) and seeing or hearing things that aren't there (hallucinations).

Causes, incidence, and risk factors:

A number of substances and medical conditions can cause psychosis, including:

• Alcohol and certain illegal drugs, both during use and during withdrawal
• Brain tumors or cysts
• Dementia (including Alzheimer's disease)
• Degenerative brain diseases, such as Parkinson's disease, Huntington's disease, and certain chromosomal disorders
• HIV and other infections that affect the brain
• Some prescription drugs, such as steroids and stimulants
• Some types of epilepsy
• Stroke

Psychosis is also part of a number of psychiatric disorders, including:

• Bipolar disorder (manic or depressed)
• Delusional disorder
• Depression with psychotic features
• Personality disorders (schizotypal, shizoid, paranoid, and sometimes borderline)
• Schizoaffective disorder
• Schizophrenia