We don't have all of this sorted out yet, but dopamine does seem centrally involved in assessing whether rewards align with expectations. This means dopamine is playing some role in all addictions, whether to dopamine-engaging drugs, or behavioral addictions including gambling, sex, and internet gaming.

But what individuals find soothing/attractive/enticing/completing may certainly involve other neurotransmitters and pathways in the brain.

I also usually point out that "lack" is almost always relative or partial. If you completely lacked dopamine, or serotonin, you're brain wouldn't function at all, you'd be dead.