On the classification of antidepressant drugs.

Clinical, pharmacologic, and biochemical profiles of antidepressant drugs have been analyzed statistically. A method derived from multivariate statistics separates mere drug potency from the spectral information contained in the profiles. The dimensionality of the spectra is also reduced and this results in a diagram of associations and dissociations between the antidepressants and their scales of observation. The spectra of antidepressants show three poles which have been labeled as D (desipraminelike), A (amitriptylinelike), and M (MAOI). Clinical spectra agree better between one another than various pharmacologic spectra do. Monoamine oxidase inhibitors are readily differentiated from the tricyclic compounds. The latter appear in the sequence: desipramine, nortriptyline, imipramine, and amitriptyline. This sequence can also be reproduced from biochemical spectra of central and peripheral blockade of norepinephrine and serotonin reuptake.