Evaluation of Global Dystonia Rating Scale as a predictor of unfavorable outcomes among acute antipsychotics poisoned patients

Worldwide, acute antipsychotic poisoning results in high morbidities and mortalities. Though extrapyramidal syndromes are commonly associated, the extent of extrapyramidal syndromes in relation to the severity of antipsychotic poisoning has not been addressed yet. Thus, this study aimed to assess the Global Dystonia Rating Scale (GDRS) as an unfavorable outcomes predictive tool in acute antipsychotic poisoning. A cross-sectional study included 506 antipsychotic-poisoned patients admitted to Tanta University Poison Control Center, Egypt, over three years was conducted. The mean GDRS was 9.1 ± 16.7 in typical antipsychotic poisoning, which was significantly higher than that of atypical antipsychotics (4.2 ± 11.5) (p = 0.003). Patients with GDRS< 20 showed significantly higher liability for all adverse outcomes (p < 0.05). However, poisoning with typical antipsychotics was associated with significantly more cardiotoxicity (p = 0.042), particularly prolonged QRS (p = 0.005), and intensive care unit (ICU) admission (p = 0.000). In contrary to the PSS, which failed to predict the studied adverse outcomes, GDRS significantly predicted all adverse outcomes (p < 0.000) for all antipsychotic generations. In atypical antipsychotics, GDRS above three accurately predicted cardiotoxicities, prolonged QTc interval, and respiratory failure with Area under curves (AUC) of 0.937, 0.963, and 0.941, respectively. In typical antipsychotic poisoning, at higher cutoffs (7.5, 27.5, 18, and 7.5), cardiotoxicities, prolonged QTc interval, and respiratory failure were accurately predicted (AUC were 0.974, 0.961, and 0.960, respectively). GDRS is an objective, substantially useful tool that quantifies dystonia and can be used as an early reliable predictor of potential toxicity in acute antipsychotic poisoning.