9 Most Outrageous Friends Fan Theories
5. Monica Developed OCD After Losing Weight
We all know and love Monica as being the clean-freak, OCD member of the group. Sure, she might not be able to imagine a world where drinks aren't placed on coasters, and her Raggedy Ann doll was the only one that wasn't raggedy, but that was just part of her character.
Another thing we know about Monica is that she used to be fat, and lost weight after a rather mean remark by Chandler at Thanksgiving. The theory is that she had OCD before she gained weight (as seen in the brief glimpse of her as a child, she wasn't actually overweight), but started comfort eating as a result of her parents obvious favouritism of Ross. Then, when she manages to lose weight, the cleaning comes back.
In The One That Could Have Been, when she's back to being Fat Monica, she's shown to be much more carefree. The OCD is always there, it's just that it changed between cleaning and eating, and is now back to cleanliness again.