"neurotransmitter that LSD worked on is seritonin?"
You would think someone would know . . .
Of course, any time you go messing with your neurotransmitters, you are causing trouble. You not only need enough of them, they need to be in balance.
Which is why anti-depressants etc. eventually fail. E.G. they can sit on the reuptake sites all they want, but if the body is not making enough serotonin due to stress, inadequate nutrition, etc., there will simply not be enough, despite the anti-depressants sitting on the reuptake sites. At best they can be a bridge, protecting the supply of active serotonin until the person builds themselves back up physically.