You may purchase Stablon OTC online. It is a serotonin booster/agonist. Another OTC isPiracetam 800 mg 60 vcaps is considered what is called nootropic medication/supplement that you may want to look into as well.
Other OTC options targeting various neurotransmitters to consider are:
5HTP, Acetyl-L-Carnitine (ALC), Deprenyl, Gerovital-H3, L-Tryptophan, NeyGeront, Nootropics , Picamilone, Pregnenolone (hormone ), SAMe
One can order Stablon and other antidepressants online from the UK without prescription through http://www.antiaging-systems.com/ and these are sent to you via postal mail.
Pregnenolone, 5-HTP, L-tryptophan, L-carnitine and SAMe and other nootropics may be purchased in the USA through various sellers. A good quality and reasonably priced you may find through www.swansonvitamins.com or www.lef.org