Fast Five Quiz: Schizophrenia Comorbidities

Stephen Soreff, MD


April 22, 2021

Figure 1. PET scan of the brain (temporal lobe) of a hallucinating patient with schizophrenia. This color-coded cerebral layer scan shows brain activity, from low (blue) to high (yellow). PET scanning relies on an injected radioactive tracer to show metabolic activity in the brain. Normal brain metabolic activity produces a roughly symmetrical pattern in the yellow areas of left and right cerebral hemispheres. PET scanning shows abnormalities of function in the brains of schizophrenic persons. Schizophrenia is characterized by delusions, hallucinations, and depression.

Persons with schizophrenia may use a variety of substances, either legal or illegal, to escape from or lessen some of the symptoms of this disorder. Cannabis use has been shown to be associated with an earlier onset of psychosis. In the setting of schizophrenia, it has also been shown to correlate bidirectionally with an adverse course of psychotic symptoms: People with more severe psychotic symptoms are more likely to use cannabis, and cannabis seems to worsen psychotic symptoms. However, findings to date have been inconsistent; other research shows that cannabis use can lead to better cognitive functioning.

Alcohol abuse, drug abuse, and in particular tobacco use are commonly seen in schizophrenia, though the connection between the two remains unclear. For some individuals, drugs offer relief from symptoms or even from the adverse effects of antipsychotic drugs, but drug use can also increase symptoms.

Comorbid substance abuse is seen in 20%-70% of patients with schizophrenia, often occurring in younger male patients. Substance abuse is associated with increased hostility, crime, violence, suicidality, noncompliance with medication, homelessness, poor nutrition, and poverty. Most people with schizophrenia are not violent. However, hallucinations and delusions may cause episodes of violence. Unfortunately, such events are often highly publicized, adding to the stigma of the disease.

Learn more about complications of schizophrenia.


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