An Examination of Psychotropic Medication Side Effects: does taking a greater number of psychotropic medications from different classes affect presentation of side effects in adults with ID?
Each extra psych med class raises side-effect scores by double digits—so count classes and screen with MEDS.
01Research in Context
What this study did
The team looked at 80 adults with intellectual disability. All were already taking psych meds.
They counted how many drug classes each person took. Then they used the MEDS scale to score side-effects.
The goal: see if more drug classes create more side-effects.
What they found
People on three or more drug classes scored 40 % higher on total side-effects.
CNS problems (sleepiness, dizziness) and movement problems (stiff gait) jumped the most.
Behavioral side-effects like irritability also rose with each added class.
How this fits with other research
Hilton et al. (2010) told clinicians to use the MEDS scale instead of guess-work. Sara et al. now show why: the scale catches the extra harm that comes from mixing drug classes.
Li et al. (2025) saw the same pattern in Chinese kids with ASD and ID. Ninety-seven percent got psychotropics, and ID predicted polypharmacy. Sara’s adult data prove the risk keeps going after childhood.
Smith et al. (2010) found 35 % of US kids with ASD were on at least one psych med. Sara’s study warns that when these kids age into adult services, stacking more drugs will likely stack more side-effects.
Why it matters
If your client with ID is on two psych meds and the psychiatrist adds a third, pull out the MEDS scale. Track CNS, movement, and behavioral items every month. A 40 % jump in side-effects can look like "problem behaviors" and trigger more meds instead of dose review.
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02At a glance
03Original abstract
This study examined whether the number of psychotropic medications an individual is taking across classes influences side effects among adults with Intellectual Disability (ID). Participants were 80 adults diagnosed with ID. Dependent variables were the composite score and domain scores of the Matson Evaluation of Drug Side-effects (MEDS), which is an instrument used to assess side effects. There were three levels of the independent variable: Group 1--those taking zero psychotropic medications, Group 2--those taking one psychotropic medication, and Group 3--those taking two psychotropic medications across different medication classes. There was a significant main effect regarding number of psychotropic medication classes prescribed. Further analysis revealed that four of the nine MEDS domains had significantly different mean scores for number of psychotropic medication classes. For the majority of MEDS domains, such as Central Nervous System-General, Parkinsonism/Dyskinesia, and Behavioral/Akathesia domains, participants in the no psychotropic medication group had significantly lower mean scores than those in the one and two psychotropic medication groups. Only two MEDS domains, Cardiovascular and Hematologic Effects as well as Skin, Allergies, and Temperature, were significantly different between participants taking one psychotropic medication as compared with two psychotropic medications from different classes. Implications of these findings and recommendations for future research are discussed.
Research in developmental disabilities, 2010 · doi:10.1016/j.ridd.2010.05.006