Aggression and violent incidents are a major concern in psychiatric inpatient care. Nutritional supplementation was found to reduce aggressive incidents and rule violations in forensic populations and in children with behavioral problems.

To assess whether multivitamin, mineral, and n-3 PUFA supplementation would reduce the number of aggressive incidents among long-stay psychiatric inpatients.

The trial was a pragmatic, multicenter, randomized, double-blind, placebo-controlled study. Data were collected from 25 July 2016 through 29 October 2019 at 8 local sites for mental healthcare in the Netherlands and Belgium. Participants were randomized (1:1) to receive either three supplements containing multivitamins, minerals, and n-3 PUFA or placebo for 6 months. The primary outcome was the number of aggressive incidents using the Staff Observation Aggression Scale – Revised (SOAS-R). Secondary outcomes were the patients’ quality of life, affective symptoms, and adverse events.

In total, 176 participants were randomized (supplements, n = 87; placebo, n = 89). Participants were on average 49.3 years old (SD = 14.5), and 64.2% were male. Most patients had a psychotic disorder (60.8%). The primary outcome of SOAS-R incidents was similar in those assigned to supplements (1.03 incidents per month; 95% confidence interval [CI]: 0.74-1.37) and placebo (0.90; 95% CI: 0.65-1.19), with a rate ratio of 1.08 (95% CI: 0.67-1.74; p = .75). Differential effects were not found in sensitivity analyses on the SOAS-R or on secondary outcomes.

Six months of nutritional supplementation did not reduce aggressive incidents among long-stay psychiatric inpatients.

No significant relationships.