The brain differences found in people with schizophrenia are mainly the result of the disease itself or its treatment, as opposed to being caused by genetic factors, according to a Dutch study.
Schizophrenia is a mental disorder that significantly affects cognition and usually contributes to chronic problems with behavior and emotion. Along with a breakdown of thought processes, the disorder is also characterized by poor emotional responsiveness, paranoia, auditory hallucinations and delusions.
People with schizophrenia are likely to have additional conditions, including major depression and anxiety.
The strong familial link of schizophrenia is thought to be as high as 81 percent, and researchers have suggested that schizophrenia-related brain abnormalities may be present in unaffected relatives, a notion that has been supported by several studies.
For the current study, Heleen Boos and a team from University Medical Center Utrecht performed structural magnetic resonance imaging (MRI) whole-brain scans on 155 patients with schizophrenia, 186 of their non-psychotic siblings, and 122 healthy controls (including 25 sibling pairs).
Researchers used the images to measure volume, cortical thickness and to map the brain anatomy in order to evaluate group differences.
Compared with healthy controls, participants with schizophrenia had strong reductions in total brain, gray matter, and white matter volumes, and significant increases in lateral and third ventricle volumes after taking into account age, gender, intracranial volume, and left or right handedness.
However, there were no significant differences in brain volume between unaffected siblings and healthy controls.
Schizophrenia patients also showed cortical thinning compared with healthy controls, and had decreased gray matter density. Again, this was not found in unaffected siblings and healthy controls.
“Our study did not find structural brain abnormalities in nonpsychotic siblings of patients with schizophrenia compared with healthy control subjects, using multiple imaging methods,” the team says.
“This suggests that the structural brain abnormalities found in patients are most likely related to the illness itself.”