These could also be thought of as internal causes (inside your brain/body) and external causes (outside your brain/body).

• Genetics. Human genes are very complicated, and researchers still don’t know if there is a specific gene or set of genes that can make someone more likely to have schizophrenia. What we do know is that if one member of your immediate family (like a parent, brother or sister) has schizophrenic tendencies, you’re more likely to as well.2-4
• Brain biology. Researchers have found that some people with schizophrenia have a slightly different brain structure to people without schizophrenia.5 There are also a number of chemicals called neurotransmitters in the brain. It appears that an imbalance of one or more of these neurotransmitters, e.g. dopamine, might also have a role to play in schizophrenia.3,4

• Stressful life events. Going through a lot of stress at any time of life can lead to mental health issues for many people, and it’s thought that these kinds of events might also trigger schizophrenia.3 Highly stressful events or traumas might be things like living/growing up with abuse or harassment, being made homeless, bereavement, divorce or losing a job.3,5 These things affect us all in different ways. What one person takes in their stride might be experienced very differently by someone else.
• Recreational drugs and alcohol. Scientists still don’t know if use of drugs or alcohol actually causes schizophrenia, and it’s not clear why some drug users go on to develop schizophrenia and some don’t. What we DO know is that using drugs or alcohol can make schizophrenia symptoms worse and can make some prescribed treatments less effective. 2,3,5