The causes of schizophrenia are not fully known. However, it appears that schizophrenia usually results from a complex interaction between genetic and environmental factors.
Genetic causes of schizophrenia
Schizophrenia has a strong hereditary component. Individuals with a first-degree relative (parent or sibling) who has schizophrenia have a 10 percent chance of developing the disorder, as opposed to the 1 percent chance of the general population.
But schizophrenia is only influenced by genetics, not determined by it. While schizophrenia runs in families, about 60% of schizophrenics have no family members with the disorder. Furthermore, individuals who are genetically predisposed to schizophrenia don’t always develop the disease, which shows that biology is not destiny.
Environmental causes of schizophrenia
Twin and adoption studies suggest that inherited genes make a person vulnerable to schizophrenia and then environmental factors act on this vulnerability to trigger the disorder.
As for the environmental factors involved, more and more research is pointing to stress, either during pregnancy or at a later stage of development. High levels of stress are believed to trigger schizophrenia by increasing the body’s production of the hormone cortisol.
Research points to several stress-inducing environmental factors that may be involved in schizophrenia, including:
Prenatal exposure to a viral infection
Low oxygen levels during birth (from prolonged labor or premature birth)
Exposure to a virus during infancy
Early parental loss or separation
Physical or sexual abuse in childhood
Abnormal brain structure
In addition to abnormal brain chemistry, abnormalities in brain structure may also play a role in schizophrenia. Enlarged brain ventricles are seen in some schizophrenics, indicating a deficit in the volume of brain tissue. There is also evidence of abnormally low activity in the frontal lobe, the area of the brain responsible for planning, reasoning, and decision-making.
Some studies also suggest that abnormalities in the temporal lobes, hippocampus, and amygdala are connected to schizophrenia’s positive symptoms. But despite the evidence of brain abnormalities, it is highly unlikely that schizophrenia is the result of any one problem in any one region of the brain.
Effects of schizophrenia
When the signs and symptoms of schizophrenia are ignored or improperly treated, the effects can be devastating both to the individual with the disorder and those around him or her. Some of the possible effects of schizophrenia are:
Relationship problems. Relationships suffer because people with schizophrenia often withdraw and isolate themselves. Paranoia can also cause a person with schizophrenia to be suspicious of friends and family.
Disruption to normal daily activities. Schizophrenia causes significant disruptions to daily functioning, both because of social difficulties and because everyday tasks become hard, if not impossible to do. A schizophrenic person’s delusions, hallucinations, and disorganized thoughts typically prevent him or her from doing normal things like bathing, eating, or running errands.
Alcohol and drug abuse. People with schizophrenia frequently develop problems with alcohol or drugs, which are often used in an attempt to self-medicate, or relieve symptoms. In addition, they may also be heavy smokers, a complicating situation as cigarette smoke can interfere with the effectiveness of medications prescribed for the disorder.
Increased suicide risk. People with schizophrenia have a high risk of attempting suicide. Any suicidal talk, threats, or gestures should be taken very seriously. People with schizophrenia are especially likely to commit suicide during psychotic episodes, during periods of depression, and in the first six months after they’ve started treatment.