Robin Williams was in many ways a genius and the world mourned when he took his own life at the age of 63. He was considered to be one the greatest comedians of the last generation and made people all over the world laugh until their stomachs hurt.

However, in Williams' private life, things were anything but funny as he struggled with his personal battles. The new HBO documentary "Robin Williams: Come Inside My Mind" explores all aspects of the comedian's remarkable life

A behind-the-curtain look at Robin Williams

Williams rarely spoke publically about his personal battles in life.

However the new documentary, “Robin Williams: Come Inside My Mind,” delves into every aspect of the comedian’s life and includes some rare footage and interviews with people who were close to Williams. The documentary featured at Sundance this year to tumultuous applause and can be seen on HBO on 16th July.

In the recently released HBO trailer, Williams can be heard to say that that standup was “survival” for him and was something he had to do. As noted by Vulture, the documentary features interviews with Whoopi Goldberg, Billy Crystal, Dave Letterman, Eric Idle and Steve Martin.

The Independent quotes Martin as saying that Robin was very comfortable when he was on stage. However, he felt that when Williams was off stage, he was just holding himself together.

In one interview shown in the trailer, Williams is asked if he ever had a fear of abandonment as a child, to which Robin replied that yes, “it is the primal fear of any child,” saying this fear “dictates how you deal with life.” He said that “every person is driven by some deep secret.” Williams went on to say there is sometimes fear about whether to run away or run into it all.

His son, Zak Williams, said his father didn’t always believe he was succeeding, adding that Robin was the most successful person he knows. Billy Crystal said Williams used to leave messages on his phone, and one message can be heard in the trailer.

The message was, “It’s Robin, hi, giving you love, goodbye.”

A ‘little spark of madness’

In between the interviews, hilarious clips from his comic appearances are shown and the trailer ends with him saying, “We are only given a “little spark of madness,” adding that should you lose it, you are nothing.

Robin Williams committed suicide in 2014 at the age of 63. In recent days, other celebrities, fashion designer Kate Spade and celebrity chef Anthony Bourdain, have also taken their lives. Should any reader in the UK feel the need for help, while considering taking that awful final step, they can contact the Samaritans on 08457 90 90 90. The trailer for “Robin Williams: Come Inside My Mind” is included here.