Clinical implications of chirality and stereochemistry in psychopharmacology.

Chirality, the concept of nonsuperimposable mirror images, is a fundamental property of biological systems and can be observed on a molecular, cellular, or organism level. Stereoisomer compounds possess the same molecular and structural formula, but they differ in their three-dimensional configurations. Chiral compounds have two mirror-image stereoisomer forms called enantiomers. Compounds containing mirror-image enantiomers in equal proportions are referred to as racemic mixtures or racemates. Racemates and their individual enantiomers can have very different pharmacological properties that are relevant in clinical psychopharmacology. Various examples of drug therapies that show the clinical importance of chirality and stereochemistry are described.