Neurocognitive performance stability in a multiplex multigenerational study of schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Genetics

Background:

• Cognitive deficits are heritable and distinguish schizophrenia risk.
• Previous longitudinal studies on neurocognitive stability are limited in duration and methodology.
• Traditional studies often focus on average performance, overlooking variability.

Purpose of the Study:

• To examine the neurocognitive stability in patients with schizophrenia, unaffected relatives, and healthy controls over approximately 5 years.
• To assess both mean performance (accuracy, speed) and intra-individual variability (IIV) using a computerized neurocognitive battery (CNB).
• To investigate patterns of change in performance and IIV within families affected by schizophrenia.

Main Methods:

• A longitudinal study involving 34 patients with schizophrenia, 65 unaffected relatives, and 45 healthy controls.
• Utilized a computerized neurocognitive battery (CNB) to measure performance accuracy and speed, as well as intra-individual variability (IIV).
• Data collected over approximately 5 years to track changes in neurocognitive measures.

Main Results:

• Patients with schizophrenia maintained stable accuracy but demonstrated slower performance across multiple neurocognitive domains compared to controls.
• Patients exhibited higher across-task IIV in speed compared to family members, who showed lower IIV.
• Patients showed an increase in IIV over time, while unaffected family members displayed a decrease in IIV.

Conclusions:

• Mean performance and IIV of speed in CNB may serve as indicators of genetic susceptibility to schizophrenia.
• Dissociable patterns of IIV change in speed between patients and relatives offer insights into disease mechanisms.
• Neurocognitive measures, including variability, provide valuable information for understanding schizophrenia risk and progression.