Derivatives of 1,2,3,4-tetrahydroisoquinoline (THIQ) having the general formula A-(CH2)n—B are provided, wherein A is THIQ or a substituted derivative thereof and B is an aryl, cycloalkylaryl, or cycloalkyl group, wherein A and B are linked to each other by an alkyl or substituted alkyl chain. The compounds are useful as selective ligands (agonists or antagonists) of central nervous system receptors, and in particular of the seratonin receptors. The compounds or their salts can be formulated into pharmaceutical in need thereof by any route of administration suitable for a desired treatment protocol and especially for the treatment of psychiatric disorders.