Reducing doses of antipsychotics in patients with bipolar disorder (BD) or major depressive disorder (MDD) may result in higher rates of inpatient and psychiatric admissions and emergency room (ER) visits, according to research presented at the 2017 Psych Congress, held September 16 to 19.

This retrospective study conducted by a team of researchers led by Sanjay Gandhi, PhD, from the Global Health Economics Department at Teva Pharmaceuticals in Frazer, Pennsylvania, sought to determine the healthcare burden associated with reducing antipsychotic dosing in patients with BD or MDD. The team used rates of all-cause and mental health-related hospitalization and ER visits as an indicator.

Using Medicaid data from 6 states (Iowa, Kansas, Mississippi, Missouri, New Jersey, and Wisconsin) collected between 2008 and 2017, the researchers studied patients ≥18 years with a diagnosis of either BD (n=23,992, 37.8% male) or MDD (n=17,776, 33.5% male) and ≥2 oral antipsychotic prescription fills following diagnosis. They reviewed the data of patients on antipsychotic monotherapy for whom the medication dose had been reduced by ≥10%, and compared it with that of patients on a stable dose for ≥91 days (number-, age-, and gender-matched controls). Patients were followed for 1 year after initial dose reduction for cases, and for 1 year after first refill following the 90-day stable dose period for controls.

Dose reductions were similar for the 10 most commonly prescribed antipsychotics (including quetiapine, aripriprazole, and risperidone) in the cohort of study participants with BD or MDD. Patients who had experienced a ≥10% antipsychotic dose reduction had higher rates of inpatient admissions compared with controls (for BD: hazard ratio [HR], 1.17; 95% CI, 1.12, 1,23; P <.001; for MDD: HR, 1.11; 95% CI, 1.05, 1.16; P <.001), as indicated by a cox regression analysis. Similar results were found for ER visits and psychiatric admission for ≥10% and ≥30% dose reductions in patients with BD or MDD, compared with their counterparts on stable-dose antipsychotics (P <.001 for all).

Among patients with BD, those with a ≥10% dose reduction demonstrated a first-year event rate of 52.1% vs 49.9% for controls (HR, 1.09; 95% CI, 1.05, 1.13); <.001). For patients with MDD, those with a ≥10% dose reduction had a first-year event rate of 51.1% vs 50.2% for controls (HR, 1.07; 95% CI, 1.02, 1.11; <.01).