Biological Factors in Schizophrenia
Schizophrenia has a strong genetic component, but it's not 100% genetic. Family members of people with schizophrenia also have higher risks for related conditions like schizotypal personality and bipolar disorder. The condition is likely polygenic (involving multiple genes) and may involve genes related to dopamine metabolism, glutamate function, and immune functioning.
Prenatal exposures significantly influence risk. Maternal infections during pregnancy (like flu or rubella), rhesus incompatibility, birth complications affecting oxygen supply, malnutrition, and major stressors during pregnancy can all increase the risk of developing schizophrenia later in life.
Brain imaging studies show enlarged brain ventricles fluid−filledspaces in people with schizophrenia, indicating less brain volume. This is especially noticeable in men and is often present at the onset of illness. Some people also experience progressive loss of brain volume in specific regions:
- Gray matter in the prefrontal cortex
- Temporal lobes
- Parts of the limbic system (amygdala, hippocampus, thalamus)
There are also reductions in white matter volume, particularly in the frontal lobe, causing difficulties with brain connectivity. Some research suggests excessive "pruning" of neural connections during adolescence contributes to these changes.
⚠️ Watch Out: Head injuries between ages 11-15 can increase schizophrenia risk, highlighting how brain development disruptions during critical periods can have long-term consequences.