Long‐acting injectable paliperidone palmitate for severe anorexia nervosa and comorbid autism spectrum disorder: A case report

TL;DR

A patient with anorexia nervosa and autism spectrum disorder showed improved stability after treatment with long-acting injectable paliperidone palmitate.

Contribution

Demonstrates the potential effectiveness of LAI paliperidone palmitate in treatment-resistant anorexia nervosa with comorbid ASD and intellectual disability.

Findings

The patient achieved psychiatric and nutritional stability over three years with no rehospitalizations.

LAI paliperidone palmitate was well-tolerated without severe adverse effects.

The treatment was effective in managing obsessive traits and nonadherence issues.

Abstract

Anorexia nervosa (AN), comorbid with autism spectrum disorder (ASD), poses significant treatment challenges due to cognitive rigidity, poor insight, and frequent nonadherence to pharmacological interventions. Although second‐generation antipsychotics (SGAs) have been used off‐label in AN, evidence for long‐acting injectable (LAI) formulations remains scarce, particularly in adult patients with neurodevelopmental disorders.

We report the case of a 27‐year‐old woman with severe AN and comorbid ASD who exhibited repeated hospitalizations due to critical underweight and persistent refusal of oral medications. Cognitive assessment revealed mild intellectual disability (IQ 56). The patient demonstrated obsessive‐compulsive traits and extreme rigidity toward food intake, and was resistant to multiple oral antipsychotics. While risperidone was tolerated, poor adherence limited its efficacy. After obtaining informed consent, LAI paliperidone palmitate was initiated (initial dose 25 mg, increased to 50 mg monthly). Following a short period of psychoeducation and lifestyle intervention, the patient maintained psychiatric and nutritional stability over a 3‐year outpatient follow‐up without rehospitalization. Her body mass index stabilized at approximately 24 kg/m2. No severe adverse effects were reported.

This case highlights the potential role of LAI paliperidone palmitate in managing treatment‐refractory AN with comorbid ASD and intellectual disability, particularly in patients with poor adherence and prominent obsessive traits. Although antipsychotics are not standard for AN, LAI formulations may offer pragmatic, sustainable benefits in selected cases. Further studies are warranted to assess long‐term safety and efficacy in this population.

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