Final answer:
Enlarged brain ventricles in schizophrenics are likely due to a mix of genetic vulnerability and environmental stress, leading to structural brain abnormalities and disrupted neurotransmission.
Step-by-step explanation:
The most likely cause of enlarged brain ventricles in individuals with schizophrenia is a combination of genetic vulnerability and environmental factors that lead to structural brain abnormalities. In schizophrenia, structural changes such as ventricle enlargement are thought to involve dopaminergic and glutamatergic neurotransmission malfunction. Studies suggest that schizophrenia involves not only genetic predisposition but also environmental stress, such as being raised in a disturbed family environment, which can contribute to the onset of the disorder. Enlargement of the brain ventricles is sometimes seen in neuroimaging studies of patients with schizophrenia, indicating loss of brain tissue and potentially contributing to cognitive and emotional symptoms.