Intelligence quotient changes over 10 years: Diversity of cognitive profiles in first episode of psychosis and healthy controls.

OBJECTIVE

This study aimed to analyse whether intelligence quotient (IQ) improves, declines, or remains stable over 10 years among FEP patients and healthy subjects.

METHODS

A group of FEP patients enrolled in a Program of First Episode Psychosis in Spain called PAFIP, and a sample of Healthy Controls (HC) completed the same neuropsychological battery at baseline and approximately 10 years later, which included the WAIS vocabulary subtest to estimate premorbid IQ and 10-year IQ. Cluster analysis was performed separately in the patient group and the HC group to determine their profiles of intellectual change.

RESULTS

One hundred and thirty-seven FEP patients were grouped into five clusters: "Improved low IQ" (9.49 % of patients), "Improved average IQ" (14.6 %), "Preserved low IQ" (17.52 %), "Preserved average IQ" (43.06 %), and "Preserved high IQ" (15.33 %). Ninety HC were grouped into three clusters: "Preserved low IQ" (32.22 % of the HC), "Preserved average IQ" (44.44 %), and "Preserved high IQ" (23.33 %). The first two clusters of FEP patients, characterized by a low IQ, earlier age at illness onset, and lower educational attainment, showed a substantial cognitive improvement. The remaining clusters demonstrated cognitive stability.

CONCLUSIONS

The FEP patients showed intellectual improvement or stability, but no decline post-onset of psychosis. However, their profiles of intellectual change are more heterogeneous than that of HC over 10 years. Particularly, there is a subgroup of FEP patients with a significant potential for long-term cognitive enhancement.