Assessment & Research

The use of clozapine in adults with intellectual disability.

Thalayasingam et al. (2004) · Journal of intellectual disability research : JIDR 2004
★ The Verdict

Clozapine helps adults with ID and psychosis, yet blood safety rules the show.

✓ Read this if BCBAs serving adults with ID in residential or forensic settings
✗ Skip if Clinicians working only with children or non-verbal ASD without psychosis

01Research in Context

01

What this study did

Doctors tracked adults with intellectual disability who started clozapine. They used simple ratings to see if symptoms got better.

The team also counted who moved to community homes and who had to stop the drug because blood counts dropped.

02

What they found

Seven out of ten adults showed at least small gains. More than half left hospital settings for community homes.

One in six had to quit clozapine when white blood cells fell. This side effect needs weekly blood draws.

03

How this fits with other research

Neuringer et al. (2007) extends these safety worries. They gave one man a protective shot called G-CSF. His blood stayed safe and he kept taking clozapine.

de Kuijper et al. (2014) seems to contradict the target paper. Their trial tapered antipsychotics and behavior still improved. The key gap: Hawley et al. (2004) started clozapine for clear psychosis, while de Kuijper et al. (2014) removed drugs that were only for "challenging behavior."

Lerman et al. (1995) and Rieth et al. (2022) show the backdrop: lots of adults with ID get antipsychotics for behavior, sometimes without strong reason.

04

Why it matters

Clozapine can be life-changing for adults with ID and tough psychosis, but you must monitor blood. If counts drop, ask about G-CSF so the client can stay on the drug. Always pair meds with behavior plans and choice-making supports to avoid unnecessary prescriptions.

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→ Action — try this Monday

Check if any adult on your caseload taking clozapine has this week’s blood results on file.

02At a glance

Intervention
not applicable
Design
case series
Sample size
24
Population
intellectual disability
Finding
positive
Magnitude
medium

03Original abstract

BACKGROUND: There are not many studies on the use of clozapine in patients with intellectual disability (ID). The authors describe a case series of patients treated with clozapine, drawn from a medium secure unit, a low secure assessment and treatment service and a community team in the London region. METHOD: A retrospective file-review of patients treated in these three settings during the time period March-June 2002 was performed (n = 24). Information was collected using a semistructured proforma. RESULTS: Of the 24 patients, 67% had schizophrenia, 17% had schizoaffective disorder and 8% had bipolar disorder. Patients had been unwell for a mean of 6 years and had been tried on a mean of four antipsychotics. The mean maximum dose of clozapine was 488 mg. The outcomes on the clinical global impression (CGI) scale showed 29% very much improved, 42% much improved, 21% minimally improved and 8% no change. 54% of the whole sample and 53% of those from the medium secure unit were discharged to homes in the community. The drug had to be stopped in four patients, of which three were because of neutropaenia. CONCLUSION: Clozapine appears to be safe and efficacious in many people with ID. Careful monitoring of side-effects is needed during therapy.

Journal of intellectual disability research : JIDR, 2004 · doi:10.1111/j.1365-2788.2004.00626.x