Long-Acting Injectable Antipsychotics May Reduce Bipolar Relapses, Suggests Study
Written By : Medha Baranwal
Medically Reviewed By : Dr. Kamal Kant Kohli
Published On 2026-09-21 15:15 GMT | Update On 2026-09-21 15:15 GMT
Hong Kong: A case series study from Hong Kong has found that long-acting injectable (LAI) antipsychotics, compared with oral antipsychotics, were associated with fewer manic or mixed relapses in bipolar disorder and lower healthcare utilization. Importantly, LAI treatment was not associated with an increase in non-psychiatric hospitalizations. The findings, published in the American Journal of Psychiatry, suggest that LAI antipsychotics may offer advantages in preventing relapse, particularly where adherence to oral treatment is challenging.
The study, led by Eunice Kehui Deng from the Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, University of Hong Kong, and colleagues, evaluated differences between LAI and oral antipsychotics in healthcare use, relapse, and safety among people with bipolar disorder.
Researchers used electronic health records from Hong Kong covering January 2004 through December 2023. The analysis included patients with bipolar disorder who had received prescriptions for both treatment approaches, allowing outcomes during LAI and oral antipsychotic treatment periods to be compared within the same individuals.
Among 17,841 people with bipolar disorder, 2,086 (11.7%) had received both LAI and oral antipsychotics. Compared with oral therapy, LAIs were associated with significantly lower rates of several healthcare and relapse outcomes.
Key findings included:
- 15% lower risk of all-cause emergency department visits with LAIs (aIRR, 0.85).
- 21% lower risk of all-cause hospitalizations (aIRR, 0.79).
- 33% lower risk of psychiatric hospitalization (aIRR, 0.67).
- 49% lower risk of hospitalization for manic episodes (aIRR, 0.51).
- 69% lower risk of hospitalization for mixed episodes (aIRR, 0.31).
- No significant difference was observed for depressive episode hospitalizations (aIRR, 1.34), nonpsychiatric hospitalizations (aIRR, 0.97), or cardiovascular hospitalizations (aIRR, 0.84).
Safety analysis showed that LAI treatment was initially associated with a higher risk of extrapyramidal symptoms (EPS), with an aIRR of 2.95. However, this difference was no longer statistically significant after the first 90 days of treatment, suggesting that closer monitoring may be particularly important during treatment initiation.
The authors noted several limitations. The study used data from Hong Kong public hospitals, which may limit its applicability to other healthcare systems. Information on illness severity, medication adherence, bipolar disorder subtype, psychosocial interventions and treatment preferences was unavailable, potentially leading to residual confounding. The study design may also have favored patients with more severe illness because participants had received both LAI and oral antipsychotics and experienced at least one outcome.
Overall, the findings suggest that LAI antipsychotics may reduce healthcare utilization and hospitalizations for manic and mixed episodes without increasing nonpsychiatric or cardiovascular hospitalizations. The researchers support their longer-term use in bipolar disorder, with careful monitoring for EPS, particularly during the initial treatment period.
Reference:
Comparison of Long-Acting Injectable and Oral Antipsychotics in Bipolar Disorder. Eunice Kehui Deng, M.Pharm., Caige Huang, B.Sc., Vincent K.C. Yan, Ph.D., Kyung Jin Lee, M.Sc., Shek-Ming Leung, M.Clin.Pharm., Vanessa W.S. Ng, Ph.D., David J. Castle, M.D., Sherry Kit Wa Chan, M.D., Francisco Tsz Tsun Lai, Ph.D., Andrew A. Nierenberg, M.D., Yue Wei, Ph.D., Esther W. Chan, Ph.D.
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