I’ve heard that some shooters use it to damp down the body’s normal small tremors and regulate the heart. Don’t know if it is bunk.
I know I’d sure try it if there were lives on the line.
Should diazepam reduce dispersion?
A quick Google search doesn’t show any hits other than forum users asking around if it’s true. I don’t think it’d really affect shooting/dispersion to such a degree that it matters in-game (both balance-wise and “realism”-wise). The hits I saw asked about it in relation to professional shooting (snipers, competitive, etc.), and I don’t think CDDA models that level of shooting enough.