Many genetic and environmental factors are risk factors for schizophrenia. The dominant model of schizophrenia is that it is a distinct neurodevelopmental disorder with no clear boundary or single cause (i.e., it is caused by multiple mechanisms).
Schizophrenia is thought to develop as a result of extremely complex gene-environment interactions involving vulnerability factors. The interactions of these risk factors are complex, as numerous and diverse medical insults can occur from conception to adulthood.
Deficits in neural circuits that affect sensory input and cognitive functions are caused by a combination of genetic and environmental factors. This theory has historically been widely accepted but impossible to prove due to ethical constraints. The first definitive proof that schizophrenia is caused by multiple biological changes in the brain was recently established in human tissue grown from patient stem cells, where the disease’s complexity was discovered to be “even more complex than currently accepted” due to cell-by-cell encoding of schizophrenia-related neuropathology.
Here are some recognized risk factors associated with schizophrenia:
- Genetic Factors: A family history of schizophrenia raises the chances of developing the disorder. Individuals with a first-degree relative (such as a parent or sibling) with schizophrenia are at a higher risk.
- Neurochemical Imbalances: Certain neurotransmitter imbalances, such as dopamine, glutamate, and serotonin, have been linked to schizophrenia. These imbalances may impair brain function and contribute to the disorder’s development.
- Substance Abuse: Substance abuse has been linked to an increased risk of developing schizophrenia, particularly during adolescence and early adulthood. Drug abuse, particularly cannabis (marijuana), may trigger or worsen symptoms in people who are already predisposed to the disorder.
- Traumatic Experiences: Childhood trauma has been linked to an increased risk of developing schizophrenia later in life, such as physical or sexual abuse, neglect, or emotional trauma. Traumatic events may play a role in the development of psychotic symptoms.
- Social Isolation and Migration: Migration and social isolation have been identified as potential risk factors for schizophrenia. Individuals who are socially isolated or go through significant cultural or social changes may be more prone to developing the disorder.
Schizophrenia typically develops between the ages of 16 and 30 (generally males aged 16-25 and females aged 25-30); approximately 75% of people living with the illness developed it during this time period. Childhood schizophrenia (very early onset schizophrenia) occurs before the age of 13 and is extremely rare (1 in 40,000). Men, on average, have a slightly earlier onset than women, with one hypothesis being the possible influence of the female sex hormone oestrogen and another being socio-cultural influences. Oestrogen appears to have a muffled effect on dopamine receptors.
