Latency to Long-Acting Injectable Antipsychotic Initiation and Psychiatric Hospitalization in First-Episode...

Objective: Long-acting injectable (LAI) antipsychotics are increasingly recommended for patients in the early phase of schizophrenia. We examined how the timing of LAI initiation affects treatment discontinuation and hospitalization duration in first-episode schizophrenia.

Methods: Using the Korean Health Insurance Review and Assessment Service claims database, we identified 6,380 patients with first-episode schizophrenia receiving continuous LAI treatment. The interval from diagnosis to LAI initiation was categorized into 6 groups (<1, 1-2, 2-3, 3-4, 4-5, and >5 years). Treatment discontinuation and the proportion of psychiatric hospitalization days during continuous LAI use were analyzed using Cox and linear regression models.

Results: Earlier LAI use increased over time, but the duration of continuous treatment declined. Patients who started LAIs >2 years after diagnosis had lower risks of discontinuation than those within the first year (2-3 years: hazard ratio [HR]=0.77 [0.69-0.87]; 3-4 years: HR=0.77 [0.68-0.86]; 4-5 years: HR=0.70 [0.61-0.79]; >5 years: HR=0.66 [0.59-0.74]). Later initiation was associated with greater psychiatric hospitalization burden, particularly among patients with prior hospitalizations (1-2 years: β=0.039, P=.039; 3-4 years: β=0.057, P=.010; >5 years: β=0.162, P <.001), and within the >5-year group, longer delays further increased hospitalization days (β=1.87×10^-4, P<.001).

Conclusion: Although delayed initiation was linked to better treatment adherence, early LAI use reduced hospitalization burden, supporting guidelines advocating earlier LAI treatment in schizophrenia.