Psychosis is caused by a complex interplay of factors including mental health conditions, physical illnesses, substance use, and traumatic experiences. Psychological causes include schizophrenia, bipolar disorder, severe depression, serious stress or anxiety, and lack of sleep. Physical conditions such as brain injuries, tumors, strokes, Parkinson’s, Alzheimer’s, HIV/AIDS, and infections can trigger psychosis. Substance-induced psychosis can result from the use of drugs like cannabis, cocaine, amphetamines, and certain prescription medications. Traumatic events such as severe stress, abuse, or bereavement also play significant roles. Genetic vulnerability and chemical imbalances in the brain, especially involving dopamine, contribute as well.

Neurobiology points to dopaminergic system overactivity and involvement of pathways in the brain such as the mesolimbic pathway, though other neurodegenerative processes also have a role. The endocannabinoid system is implicated, with substances like THC potentially inducing psychotic symptoms. Diagnosis involves careful assessment to exclude other causes and identification of symptoms like hallucinations, delusions, and disordered thinking. Early treatment with antipsychotic medications and supportive therapies improves outcomes.

In summary, psychosis arises from a combination of genetic, neurological, psychological, environmental, and substance-related factors, making it a complex condition with diverse causes requiring comprehensive evaluation and personalized treatment.