Robin Williams was reportedly sleeping up to 18 hours a day before his death.

The 63-year-old actor, whose body was found by his personal assistant after he hanged himself at his home in Tiburon, California on Monday (11.08.14), also ''wasn't eating'' in the weeks before taking his own life due to his severe depression.

A source told gossip website ''Robin had been suffering from depression and would often sleep a majority of the day and night. His bedroom had black out curtains, because Robin didn't want light in his bedroom.

''He wasn't eating and was just having problems getting out of bed. He would often complain that he was just so tired, even after sleeping 20 hours.''

The 'Mrs. Doubtfire' actor sought relief from his personal struggles in his work for much of his life.

The insider said: ''Robin's comedic talent came from the sadness he had in his personal life . . . the laughter was his coping mechanism.

''He had been battling depression for most of his adult life . . . it was always there.''

Family members and friends have started planning the Oscar-winning star's private funeral.

The source said: ''Everyone is obviously just stunned that Robin committed suicide . . . his family is holed up together and beginning to make plans for a very private funeral.

''There will most likely be a public memorial to celebrate his life that his fans can be a part of.''