I have 4 insane sims in a group home. Now I know sims with the insane trait change into inappropriate outfits, such as swimwear around the house, swimming/sleeping in formal etc. but its always been outfits they're assigned via CAS or Stylist.  My sims are changing into outfits they weren't given, one even got out the shower and had no hair! LOL (shaved head look).  I don't know where these outfits are coming from.  Is this normal for insane sims to randomly pick unassigned outfits?  I don't use dresser.

Yep pretty much

I wonder that too igazor, but then we are talking agout MY game, and as you know from past posting, my sims seem to do things no other sims do LOL  It is weird though.   I don't usually play with this trait either, but thought I'd see if it makes the game any more fun.... it doesn't. In fact, it gets quite boring to see them talk to themselves all the time and the constant changing of outfits gets irritating, especially when they seem to pick their own clothing!

I haven't seen this either.  All my insane sims stick to outfits I've picked out and randomly choose which category.  I remember way bay when I played my first insane sim I went through the trouble of picking out amusing outfits for 3 indexes in every clothing category expecting the sim to randomly change into any of those outfits.  But that never happened.  The sim only stuck to outfits currently assigned to index 1.

The only time I've seen any sim change into a 'random' outfit is when the sim is self-employed, decides to change into his or her career outfit and I haven't bothered to pick that out ahead of time.  So, the outfit is usually a surprise to me.  I don't ever see random hair, but then I usually lock hairstyles to be the same for every category.

I also lock hairs for every outfit except for the occasional time I change for formal. My sims seem to have a mind of their own and in MY game autonomy is an understatement LOL