Lesson 3 of 7
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What Causes Psychosis?

Stressful Events & Psychosis

Stressful Events & Psychosis

There are different ideas about why psychotic experiences become a problem. But it’s generally thought that some people are more vulnerable to them, and that very stressful or traumatic events make them more likely to occur. A person’s own attitude to their experience, as well as the attitude of those around them, also plays a part.

People who have been through very difficult or unhappy events may need to push their feelings and memories away because they are so painful. Some therapists suggest that psychotic experiences are an expression of these overwhelming feelings and forbidden thoughts. In other words, these are a way of coping with life events, such as abuse.

Biochemical/Genetic Factors that Lead to Psychosis

The experiences involve biological changes in brain structure or brain chemistry, but whether these are the cause or the effect of the psychotic experience is impossible to say. Research into whether there’s an inherited vulnerability is inconclusive. If one member of a family is diagnosed with schizophrenia or bipolar disorder then there seems to be more chance of another family member being similarly diagnosed. But no single gene has been found to be responsible. Early experiences in life may be important in helping to prevent problems. One theory suggests that over-critical or over-protective families make people more vulnerable to psychosis.

Social & Environmental Factors that Lead to Psychosis


It’s also been suggested that they are traits we all share, to varying degrees, but which are interpreted differently, according to our culture or social standing. Someone regarded as ‘charmingly eccentric’ in an artistic community, may be condemned as ‘abnormal’ elsewhere. It’s been pointed out that a very high proportion of disadvantaged young men are likely to receive a diagnosis of schizophrenia, many of them from the Black community. Misdiagnosis may come from misunderstanding. Some people suggest that it is evidence of underlying racism.

Upbringing & Psychosis

All our experiences colour the way we interpret what happens to us in life. Many people who have psychotic experiences seem to have been physically, emotionally or sexually abused. Their experience of life can make them anxious and suspicious about other people, as well as lowering their self-esteem. So, if they have a psychotic experience, it may be particularly frightening and disturbing to them. This sets up a vicious, negative circle. For instance, someone who hears voices may think they are being bugged. They may become afraid that the secret service is persecuting them and interpret everything they see as supporting this view. They may start to avoid all streets with white vans in them, or refuse to go outside at all. Feeling threatened and on constant alert can be very frightening, tiring, and preoccupying. It may interfere with sleep and daily life, and make it very hard to trust anyone.

Recreational Drugs

Researchers still aren’t sure whether using recreational drugs directly causes psychosis but you may be more likely to hear or see things as a result of taking certain recreational drugs, like cannabis, amphetamines (including speed and ice), LSD (acid), magic mushrooms, ketamine, ecstasy and cocaine. There is considerable evidence that psychotic experiences are connected to using cannabis in some vulnerable people. If you have already experienced psychosis, using recreational drugs can make the symptoms worse, in particular, if you take high-potency cannabis (‘skunk’).

Physical Factors that Lead to Psychosis

Almost anyone can have a brief psychotic episode. It may result from a lack of sleep (through severe jet lag, perhaps). You may experience hallucinations (seeing or hearing things that aren’t there) if you have a high fever (including malaria, pneumonia, ‘flu and other viral infections), head injury, or lead or mercury poisoning. If you have Alzheimer’s disease or Parkinson’s disease you may also experience hallucinations or delusions

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