Individuals with established cognitive limitations exhibit signs of early cerebral hypoplasia, whereas neuropsychologically normal and deteriorated patients display brain tissue loss consistent with progression or later cerebral dysmaturation, according to a study of 228 individuals.
131 participants with psychosis and 97 healthy subjects underwent structural magnetic resonance imaging and neuropsychological testing. They were divided into neuropsychologically normal and impaired groups. The latter group was divided into groups reflecting average (neuropsychologically impaired) and below average (neuropsychologically compromised) premorbid intellect. Investigators compared intracranial volume (ICV) and total brain volume (TBV).
Among the results:
• Neuropsychologically impaired patients exhibited smaller TBV, reduced grey matter volume in frontal, temporal, and subcortical brain regions, as well as widespread white matter volume loss vs healthy participants.
• Neuropsychologically compromised patients had smaller ICV than healthy, neuropsychologically normal, and deteriorated patients, but relatively normal TBV.
• Deteriorated patients exhibited smaller TBV compared to healthy participants, but relatively normal ICV.
• When adjusted for ICV, TBV was reduced in neuropsychologically normal patients, which researchers did not expect.
Citation: Woodward N, Heckers S. Brain structure in neuropsychologically defined subgroups of schizophrenia and psychotic bipolar disorder. Schizophr Bull. 2015;41(6):1349-1359.