You expect an after-school special. Instead you get something that looks you in the eye and doesn't flinch. Refrain treats addiction not as a moral failure but as a quiet kind of drowning, the kind that happens in a bedroom while everyone else is living. One episode is enough because it doesn't need to convince you of anything, it just shows you what it costs, and lets that sit. Most anime about real suffering distances you with spectacle. This one doesn't. It stays close, and that's what makes it brutal.
Refrain is a single-episode OVA made as an educational short film. Its subject is the abuse of paint thinner as an inhalant, and its purpose is to inform viewers about that danger rather than to entertain them. Umanosuke Iida directed the short.