The top left (Marcia) became addicted to a variety of drugs and recieved treatment for it multiple times. The bottom left (Cindy) was involved in a pornographic film. And bottom right (Bobby) became a Grateful Dead "Deadhead" and was later arrested for a DWI.
Also bottom middle, the "dad" "Mike", is gay. Not that there is anything wrong or "thuggish" about that, I just feel compelled to throw that fun fact in there. It adds a whole new level of entertainment to rewatching old Brady bunch episodes.