Cultural perceptions of mental disorders such as psychosis or schizophrenia are believed to be caused by jinn (spirits) in Muslim majority countries. Furthermore, those in Arab-Muslim societies perceive those who act differently than the social norm as “crazy” or as abnormal behaviour. This differs from the lived experience of individuals in India and how they attain their perspectives on mental health issues through a variety of spiritual and healing traditions. In Cambodia, hallucinations are linked with spirit visitation, a term they call “cultural kindling”. These examples of differences are attributed to culture and the way it shapes conceptions of mental disorders. These cultural differences can be useful in bridging the gap of cultural understanding and psychiatric signs and symptoms. Diagnosis
To make a diagnosis of a mental illness in someone with psychosis other potential causes must be excluded. An initial assessment includes a comprehensive history and physical examination by a health care provider. Tests may be done to exclude substance use, medication, toxins, surgical complications, or other medical illnesses. A person with psychosis is referred to as psychotic. Delirium should be ruled out, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, indicating other underlying factors, including medical illnesses.
Causes or triggers include:
Falling asleep and waking: hypnagogic and hypnopompic hallucinations
Bereavement, in which hallucinations of a deceased loved one are common
Severe sleep deprivation
Extreme stress (see below)

Trauma and Stress
Traumatic life events have been linked with an elevated risk of developing psychotic symptoms. Childhood trauma has specifically been shown to be a predictor of adolescent and adult psychosis. Individuals with psychotic symptoms are three times more likely to have experienced childhood trauma (e.g., physical or sexual abuse, physical or emotional neglect) than those in the general population. Increased individual vulnerability toward psychosis may interact with traumatic experiences promoting an onset of future psychotic symptoms, particularly during sensitive developmental periods. Importantly, the relationship between traumatic life events and psychotic symptoms appears to be dose-dependent in which multiple traumatic life events accumulate, compounding symptom expression and severity. However, acute, stressful events can also trigger brief psychotic episodes. Trauma prevention and early intervention may be an important target for decreasing the incidence of psychotic disorders and ameliorating its effects.A healthy person could become psychotic if he is placed in an empty room with no light and sound after 15 minutes a  phenomenon known as sensory deprivation.Neuroticism, a personality trait associated with vulnerability to stressors, is an independent predictor of the development of psychosis.