The Correlations between Results of Short-form Wechsler Adult Intelligence Scale-III and Demographic/Clinical Factors in Patients with Schizophrenia: Preliminary Findings

The Correlations between Results of Short-form Wechsler Adult Intelligence Scale-III and Demographic/Clinical Factors in Patients with Schizophrenia: Preliminary Findings

Objectives: Previous studies showed that the illness duration is related with cognitive performance in patients with schizophrenia. The Wechsler Adult Intelligence Scale (WAIS) has been used extensively to assess the cognitive function in schizophrenia in both research and clinical practice. In this study, we intended to analyze whether a correlation exists between the indices of short form WAIS III and demographic/clinical data (including illness duration, age at onset, and years of education). Methods: We included 34 patients with schizophrenia from a tertiary hospital in Taiwan. Each participant received assessment with the short form WAIS III, consisting of seven core subtests. It provided scores for verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ), full scale intelligence quotient (FSIQ), and four secondary indexes (verbal comprehension, working memory, perceptual organization, and processing speed). Data were analyzed for correlation. Results: The results showed that patients’ age at onset was significantly negatively correlated with years of education (p < 0.05). Significantly positive correlations existed between years of education and WAIS III, including VIQ (p < 0.01), PIQ (p < 0.05), FSIQ (p < 0.05), VC (verbal comprehension) (p < 0.05), PS (processing speed) (p < 0.05), similarities (p < 0.05), information (p < 0.05), picture completion (p < 0.05), and digit symbol coding (p < 0.05). The negative correlations also significantly existed between age at onset and WAIS III (p < 0.05), including VIQ (p < 0.05), FSIQ (p < 0.05), PO (Perceptual Organization) (p < 0.05), similarities (p < 0.05), arithmetic (p < 0.05), and block design (p < 0.05). The significant positive correlations were also found between illness duration and WAIS III, including PS (p < 0.05), digit span (p < 0.05), and digit symbol coding (p < 0.01). Conclusion: The study that positive correlations existed between illness duration and cognitive function differs from previous studies. Those preliminary results also suggest that the education can maintain cognitive function, at least partially, even those have early onset schizophrenia.