Turns out I was right. Both are SSRIs, and the former is the S-enantiomer of the latter. Not exactly. You're right that escitalopram is the S-enantiomer; cital

Turns out I was right. Both are SSRIs, and the former is the S-enantiomer of the latter. Not exactly. You're right that escitalopram is the S-enantiomer; citalopram is the racemic mixture of R- and S-enantiomers (of which only S- has the antidepressant effect).