Any life-changing event causes mental trauma. A therapist friend of mine once said that marriage is traumatic and can cause a person to go into survival mode, deep depression, or experience any other psychological distress. Hamlet experiences the loss of his father, the quick marriage of his mother to his uncle, and the revelation that his uncle killed his father. That's pretty traumatic! If it weren't for the fact that Hamlet has the goal to reveal this information he may have gone to that deeper, darker place like Ophelia did. Ophelia, on the other hand, was fragile. She was young and impressionable and her father manipulated her. She, too, didn't have one of her parental figures around. Had Ophelia's mother been with her, she probably would have had more support in her own life to conquer the manipulation and confusion that surrounded her during the time of the story. Shakespeare was definitely suggesting that madness manifests itself differently in different people.