I have a 20 yo ASD with good verbal skills in residential care since middle school who's been on all the usuals for explosive violence, sexually inappropriate behavior, and chronic irritability. He admitted to a group home I visit about 6 months ago on:

Asenapine 10 mg sl bid

Depakote ER 500 mg bid (level=99)

Trazodone 100 mg qhs

Levothyroxine 25 mcg, 1 tab q MWF and 1.5 tabs q Sun/Tue/Thu/Sat

Metformin 500 mg bid

Famotidine 20 mg daily

A month ago he began complaining of AH/VH and shared delusions of a tall Native American named Fred following him around and threatening to kill him with an ax. He spent 7 days in an ER then 7 days in a psych unit where he was diagnosed with schizophrenia and paliperidone 3 mg daily was added.

Shortly after discharge he started stuttering and its been getting worse. During my last Zoom he could barely speak more than a sentence. He's still delusional and suffering AH/VH but he's been more cooperative and is participating in groups.

A recent lit review mentions "86 episodes of stuttering in 82 cases." Given the millions on antipsychotics, kinda rare. But perhaps underreported. Clozapine --famous for not so much the EPS-- has the most case reports.

The most episodes of DIS were related to antipsychotic drugs (57%), mostly including clozapine, followed by central nervous system agents (11.6%) and anticonvulsant drugs (9.3%). The majority of the cases were male and between the ages of 31 and 40 years. Repetitions were the most frequent core manifestations of DIS. In 55.8% of the episodes of DIS, the offending drug was withdrawn to manage stuttering, which resulted in significant improvement or complete relief of stuttering in all cases. Based on the suggested pathophysiological mechanisms for developmental stuttering and neurotransmitters dysfunctions involved in speech dysfluency, it seems that the abnormalities of several neurotransmitters, especially dopamine and glutamate, in different circuits and areas of the brain, including cortico-basal ganglia-thalamocortical loop and white matter fiber tracts, may be engaged in the pathogenesis of DIS. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8900588/pdf/WJP-12-236.pdf

Nice to know that "Asenapine, in a limited open-label trial for stuttering, indicated improved fluency on well-tolerated doses of 5–10 mg (Maguire et al., 2011)." https://www.frontiersin.org/articles/10.3389/fnins.2020.00158/full

I'm probably going to d/c paliperidone but there's a fair chance this will destabilize the patient and he'll be back in the ER. Hopefully our state will find an inpatient psych bed someplace. I don't think that's a bad outcome because group home staff aren't trained in the management of acute psychosis. But I'll have to make sure the guardian and all the others involved are okay with the plan before I write the order.

It's probably a long shot but if anyone has experience with drug induced stuttering, I would love to compare notes.