Earlier quoted context omitted.
Nicotine has antidepressive effects through increasing bioavailability of serotonin. It also shines as an antipsychotic. I’m failing to find the study right off but something like 80-90% of schizophrenics are smokers. Buspar works in smoking cessation therapy as it helps balance the drop in serotonin when quitting smoking.
Doesn’t it also provide dopamine, which a depressed person might not be getting from their life activities?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946180/
Edit: er, sorry, you were probably talking about Buspar, not nicotine in regards to dopamine. Buspar does increase seratonin and dopamine, both of which are tickled to varying degrees by nicotine.