Aripiprazole lauroxil (AL), a new long-acting injectable antipsychotic, demonstrated safety and efficacy in treating acute exacerbation symptoms of schizophrenia in a 12-week placebo-controlled trial of two doses of AL (441mg and 882mg) administered every 4weeks. We performed a post hoc analysis of this trial to evaluate the efficacy of AL in the subgroup of patients with severe psychotic symptoms, defined as those with baseline Positive and Negative Syndrome Scale (PANSS) Total score above the median score of 92 (n=309). Change from baseline to Day 85 in PANSS Total score; Positive, Negative, and General Psychopathology subscale scores; and overall response rate were assessed. Statistically significant and clinically meaningful improvements in PANSS Total score were demonstrated with AL 441mg and AL 882mg, with placebo-adjusted differences of -14.7 (p<0.0001) and -16.6 (p<0.0001), respectively. Significant and clinically meaningful findings with both doses of AL were also demonstrated for the PANSS subscales and responder rates. Overall responder rates at Day 85 were significantly greater for AL 441mg (49%; p<0.001) and 882 mg (61%; p<0.001) groups vs. placebo (18%). Common adverse events (>5%) were schizophrenia, akathisia, headache, insomnia, and anxiety. AL demonstrated robust efficacy in treatment of the subgroup of patients experiencing severe psychotic symptoms. Both doses (441mg and 882mg) were effective, with numerically greater improvement in symptoms and proportion of responders favoring the higher dose arm. Both doses had a side effect profile consistent with the known safety profile of aripiprazole.