A Randomized Placebo-Controlled Cross-Over Pilot Study of Riluzole for Drug-Refractory Irritability in Autism Spectrum Disorder.

Crossman et al. (2018) gave 14 teens and young adults with autism either riluzole or a sugar pill for five weeks. Then they switched the groups so every teen tried both pills.

The team watched for changes in irritability using the ABC-I scale. They kept the dose at 200 mg per day the whole time.

Riluzole did not beat the placebo. Irritability scores stayed the same in both parts of the cross-over.

The drug was safe—no one dropped out—but it simply did not help.

Eisenhower et al. (2006) saw big wins with low-dose risperidone in a similar cross-over design. Risperidone cut irritability by half in about half of clients. The different result shows that not all pills work the same way.

Calamari et al. (1987) tested fenfluramine and also got nothing, just like riluzole. Two null drug trials remind us that medicine for autism irritability is hit-or-miss.

Hattier et al. (2011) reviewed dozens of tiny drug studies and found most use different rulers to measure behavior. Crossman et al. (2018) used the same ABC-I scale as many others, so their null finding is easier to compare.

You now have solid evidence that riluzole 200 mg is not worth trying for drug-refractory irritability. Save client time, insurance money, and side-effect risk. When medicine fails, turn back to behavior plans or explore risperidone with medical colleagues instead.