"affecting a person's mental state," especially "of or pertaining to drugs that affect mental states," 1956, from psycho- + -tropic, from Greek tropos "a turning," from trepein "to turn" (from PIE root *trep- "to turn"). Hence, what "turns" the mind.

"of or pertaining to the understanding, mental, intellectual," 1860, with -ic + Greek noēma "a perception, a thought," from noein "to see, perceive, have mental perception," from noos "mind, thought," which is of uncertain origin. Related: Noematical (1680s); noematically.

1620s, "throwing back rays or images, giving reflections of objects, reflecting," from reflect + -ive. From 1670s as "of or pertaining to (mental) reflection, taking cognizance of the operations of the mind." By 1820 as "having a tendency to or characterized by (mental) reflection, meditative, thoughtful." Related: Reflectively; reflectiveness.

"having a mental or psychological origin or cause," 1884, from psycho- + -genic.

also psycho-sexual, "involving the mental and emotional aspects of sexuality," 1891, from psycho- + sexual. Related: Psychosexually.