Late-Life Schizophrenia Associated With Antioxidant System Disturbance

schizophrenia concept
schizophrenia concept
With patients with schizophrenia exhibiting abnormalities in the key antioxidant enzyme, superoxide dismutase (SOD), although findings have been inconsistent, there haven’t been many studies which investigated SOD in late-life schizophrenia (LLS). Researchers investigated changes in SOD activity and what relationship there was between SOD activity and psychotic symptoms, as well as cognitive deficits in LLS.

Patients with late-life schizophrenia (LLS) were associated with disturbances in the antioxidant system. These findings were published in BMC Psychiatry.

Men (n=32) with LLS and healthy controls (n=28) were recruited from the Hui-Long-Guan hospital in China. Study participants were evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Positive and Negative Syndrome Scale (PANSS). Blood samples were also measured for enzymes.

Patients and controls were aged mean 63.63±2.87 and 63.96±3.16 years. They had 10.0±2.81 and 7.89±3.48 years of education, 25% and 89.3% were married (P <.001), and 68.8% and 0% were smokers (P <.001), respectively.

The LLS cohort had an onset of symptoms at age 27.06±6.11 years, 78.1% were on atypical antipsychotics, and they had been taking their current antipsychotic medication for 50.39±50.69 months. PANSS total score was 65.87±10.46, positive symptom subscore was 13.71±5.15, negative symptom subscore was 24.16±5.98, and general psychopathy subscore was 28±4.66.

Patients with LLS had significantly lower RBANS total scores (F, 13.94; P <.001), delayed memory (F, 24.73; P <.001), immediate memory (F, 13.70; P =.001), and language (F, 12.76; P =.001) index scores. Group differences were not observed with attention and visuospatial index scores.

The LLS cohort had significantly higher superoxide dismutase (SOD; F, 31.43; P <.001) than the copper and zinc isoform of SOD (F, 8.12; P =.006). No difference was observed for the manganese isoform of SOD (F, 0.56; P =.46).

Among the LLS group, SOD levels were positively correlated with a higher PANSS total score (r, 0.47; P =.008) and negative symptom scores (r, 0.57; P =.001) and negative correlations were observed with RBANS total score (r, -0.44; P =.013), language performance (r, -0.53; P =.002), and immediate memory performance (r, -0.38; P =.033). After Bonferroni correction, the correlation between PANSS total score, negative symptom score, and language performance remained significant.

Nearly half of the variance in SOD activity (47.3%) was explained by RBANS total score (b, -0.36; P =.022), years of education (b, 0.44; P =.006), and marital status (b, -0.32; P =.037).

This study may be limited by the fact that patients had been hospitalized long-term which may have affected both cognition and SOD levels.

These data indicated that SOD activity was significantly increased among patients with LLS. Additional study is needed to assess the role of antioxidant enzymes in schizophrenia.

Reference

Huo L, Lu X, Wu F, Chang C, Ning Y, Zhang XY. Elevated activity of superoxide dismutase in male late-life schizophrenia and its correlation with clinical symptoms and cognitive deficits. BMC Psychiatry. 2021;21(1):606. doi:10.1186/s12888-021-03604-5