Dietary supplements for aggressive behaviour in people with intellectual disabilities: A randomised controlled crossover trial.
David A A Gast, Robert Didden, Johanna J Westera and 3 others
PMID 36224110WHAT IT FOUND
Daily vitamin, mineral, and omega-3 supplements did not reduce aggressive incidents or improve quality of life in people with intellectual disabilities compared to placebo.
The study found no benefit for the primary outcome of aggression frequency.
Key findings
01There was no significant difference in the mean number of aggressive incidents per day between participants receiving dietary supplements and those receiving placebo.
02Quality of life scores did not change significantly differently between the active supplement group and the placebo group.
03Adverse events were reported by a similar proportion of participants in both the active supplement and placebo groups.
STILL TO COME
How it was doneWhat they found
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What it does not show
Nearly 30% of the study trajectories occurred during the COVID-19 pandemic, which significantly increased aggression incidents and may have masked any potential effect. The crossover component included only 24 participants, which is a small and selected sample. Support staff reported that the MOAS scale was difficult to apply to people with severe intellectual disabilities, particularly for rating verbal aggression in non-verbal individuals. The washout period for the crossover phase may have been insufficient to clear the effects of micronutrients from the first phase.
Declared interests
The study was funded by the Healthcare Insurance Fund in the Netherlands. Bonusan, the manufacturer of the supplements, donated the trial supplements and placebos but had no role in the study design or analysis.
The easy way to misread this
Do not assume supplements are ineffective because the trial was small or poorly blinded. The trial was well-powered for the primary outcome, had high adherence, and successful blinding. The null finding is robust for this population, although the pandemic context adds uncertainty.