Yes, at least in the TNG Generation where people start to de-evolve it’s because they catch a disease from Barclay. Heck, they even name it after them.
And I LOVED DS9. Ferengis started out villains, became more comic (Menage A Troi), and then like the Klingons developed nuance. I mean, look at the differences between Quark and his brother Rom–not to mention Quark’s son Nog. . .
The only one who really didn’t have much of a chance to develop was Ezri Dax because she was only in one season, though they gave her a LOT of episodes in that season including Prodigal Daughter. Actually, Ben Sisko as a father was one of the few really good examples of a parent-child relationship in DS9. Kira Nerys found out some very unhappy things about her mother, Odo’s relationship to the Bajoran scientist who discovered his sentience was rather stormy, Worf’s relationship with Alexander was fairly rocky in its later stages, the O’Brien’s had an infant and a daughter who went from pretty much preschool to barely preteen (aside from that one time-jump) so they didn’t have to deal with adolescence, Dr. Bashir’s parents unintentionally outed him being genetically enhanced, Ben Sisko’s FATHER kept it from him that his mother wasn’t the woman he called Mama but rather a woman named Sarah whose body was commandeered by one of the Prophets in order to engineer the birth of the Emissary. . Gul Dukat loved his illegitimate daughter and went insane when she was killed. Well, at least the parents of the adult and adolescent children were pretty much equally problems male AND female, it wasn’t the Disneyesque ‘stepmother villain’, absent mother, and klutzy dad dynamic!