When a gambling addict spends money on a bet, they're actually spending that money on a moment of hope. After the bet is placed but before the cards fall, they can live in a place where there is at least a possibility that they can make enough money to escape their problems. That moment of possibility is experienced as hope, and it's a feeling that's truly addictive to the hopeless.

It's scary like all addiction, but particularly sad at its core.

i've always wondered at the intimate relation between risk, dopamine, anticipation, and utility. I'm not an expert and only going by amateur armchair observation, but i suspect that evolution has spent a lot of attention on the problem of non-guaranteed rewards, and the phenomenon of gambling addiction is merely a reflection of that, just like how that of adhd is a reflection of ancient humans needing to be overly alert for subtle signs of danger (or something like that, not an expert)

That "live in a place with possibility" surely triggers the anticipation part of dopamine (which is what it really is, more so than the pleasure part). Dopamine is also intimately connected to movement: i.e. the shakes for people with neurological conditions as well as addicts going through withdrawal or about to relapse.