Preliminary analysis of positive and negative syndrome scale in ketamine-associated psychosis in comparison with schizophrenia
Journal of Psychiatric Research December 24, 2014 Ke Xu, J. Krystal, Y. Ning et al. 65 citations
Ketamine, a drug that blocks NMDA glutamate receptors, produces symptoms resembling schizophrenia. Analyzing the Positive and Negative Syndrome Scale (PANSS) in four groups—135 healthy people given ketamine or saline, 187 chronic ketamine abusers, 154 early-course schizophrenia patients, and 522 chronic schizophrenia patients—revealed five similar symptom dimensions (positive, negative, cognitive, depressed, excitement/dissociation) across all groups. The chronic ketamine group's symptom structure more closely matched the schizophrenia groups than the acute ketamine group did. Symptoms were milder in ketamine users than in schizophrenia patients (Cohen's d = 0.7). The findings suggest ketamine-induced psychosis shares symptom dimensions with schizophrenia, though confounding factors warrant caution.