Some seek fame to fill a void, a celebrity psychologist told Good Morning Britain, but it "may never be enough."
Celebrities can be attracted to fame because "there's a need for attention" stemming from "a lack of attention, a lack of nurturing when they were growing up," Yvonne Thomas said.
"If you become famous you have the world potentially - like with Robin Williams - that can love you."
But, for some, she said, it "may never be enough" to fill the void.
Robin Williams' daughter has left social media after receiving abusive messages in the wake of her father's death.
Radio station talkSPORT has apologised after presenter Alan Brazil said he lacked sympathy for actor Robin Williams, who took his own life.
He played a wide range of roles but Robin Williams captured the hearts of millions with his performances.