Reliability of the Matson Evaluation of Drug Side Effects Scale (MEDS).
The MEDS checklist is a quick, reliable way to spot medication side effects in adults with intellectual disability.
01Research in Context
What this study did
Bacon et al. (1998) tested the Matson Evaluation of Drug Side Effects Scale (MEDS).
They wanted to know if two raters would score the same client the same way.
The study used adults with intellectual disability who took psychoactive drugs.
What they found
The MEDS showed excellent inter-rater reliability and good internal consistency.
In plain words, different staff members agreed on what side effects they saw.
The checklist can be trusted to track drug side effects in clients with ID.
How this fits with other research
Hilton et al. (2010) later used the same MEDS scale to screen for tardive dyskinesia in adults on long-term antipsychotics. This extends the 1998 work into everyday clinical use.
Vassos et al. (2023) reviewed mental-health measures for adults with ID. Only four tools had both good reliability and any validity data. MEDS was not among the four, but the review focused on mood, not side effects. The papers do not clash; they look at different targets.
Drijver et al. (2025) introduced the new DIAB adaptive-behavior scale and also reported excellent inter-rater reliability, echoing the MEDS psychometric pattern.
Why it matters
If you work with adults who take antipsychotics or mood meds, keep a copy of the MEDS checklist at the nurses' station. Use it each month to spot tremors, drooling, or weight gain early. One extra rating per month can catch side effects before they snowball into hospital visits.
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02At a glance
03Original abstract
The potential negative effects of psychoactive medication are well documented. Given the high rate of their use in persons with mental retardation, the need to assess and identify these negative effects is great. The Matson Evaluation of Drug Side Effects (MEDS) was designed to evaluate commonly identified side effects with a psychometrically sound checklist. The initial psychometric properties of this scale are presented and discussed. An examination of interrater reliability and internal consistency revealed that the MEDS has excellent consistency across raters and good internal consistency. Potential uses for the scale and directions for future research are reviewed as well.
Research in developmental disabilities, 1998 · doi:10.1016/s0891-4222(98)00021-3