Hi, welcome to BL / PD
Be very careful mixing lithium with drugs, it can easily give you seizures if you combine it with something like LSD. Salvia is very atypical for a psychedelic / dissociative, in the chemical constitution and the way it acts in the body. I don't think it's terribly well understood, but interactions with other drugs probably cannot be compared easily. It is not a serotonergic psychedelic so it may be physically more safe... but I am not really sure.
Another problem with salvia is that it is very potent and usually poorly measured for dosage, so many people get very unpredictable and intense effects. I don't know what the risks would be for you getting manic or depressive episodes but I'd wager that it may not do you any favors regarding mental stability.
Let alone further complications by taking added Lexapro which makes your medication condition more delicate... I would suggest avoiding Salvia like treezy z said. You may wanna consider avoiding drugs generally, but ones that really seem like asking for trouble are serotonergic ones like LSD and mushrooms cause of the lithium, and drugs that are potentially very intense and disturbing like salvia or highly influential on mood, drive and excitement.
Have you read up on salvia divinorum, do you understand what a breakthrough experience can entail?
It is wise that you come to the forum for advice before trying this, perhaps ideal is to do it before spending the money on drugs I guess... maybe you have friends who are into this sort of thing who are better suited?
