In episode 17 of the French cartoon Spirou & Fantasio, it contains both physical and mental male AR. A _link_ to the episode can be found below.https://www.youtube.com/watch?v=lq8JDgL7NNo&t=882s
The character The Count, an old scientist, physically regresses over the entire episode though most of the changes happen offscreen. At the 14:30 mark though, it does show him regressed to a baby sitting in oversized clothes then mentally regresses to a baby shortly after. Towards the end, he reverts back offscreen.
The character Fantasio also mentally regresses to a baby around the 11:00 mark thanks to a brainwash-esque helmet.
I copied a translated copy of the episode summary below.
Spirou and Fantasio come to spend a quiet weekend in the castle of the Comte de Champignac. Alas, inadvertently, Fantasio makes the count drink an elixir of youth that the scientist developed in his youth. And the product is devilishly effective. The Count finds his thirty years, his dynamism and his dark hair. But things get complicated when it turns out that the process is continuing. A countdown begins for our heroes who must find an antidote, at the risk of seeing their learned friend irreversibly rejuvenate. Alas for them, by rejuvenating, Champignac finds a rebellious character that they did not know him!