Elon Musk Breaks Down During Interview

Elon Musk lost it during an interview as he talked about Ambien use, exhaustion and isolation.

Musk boomeranged from laughter to tears during an interview with the NY Times. He acknowledged using Ambien, saying, "It is often a choice of no sleep or Ambien." Members of the Tesla Board of Directors have worried Elon doesn't sleep after taking Ambien ... he tweets, and it has caused the company problems ... most recently when he tweeted he wanted to take the company private.

The Times went on to claim some board members believed Musk occasionally used recreational drugs.

He went on to say he's constantly exhausted because of his workload and it's compromised his health. He claims he works up to 120 hours a week and has not taken more than a week off in 17 years. The last time he was off the clock for more than a week ... 2001, when he had malaria.

Musk, who turned 47 in June, said he spent the entire day and night of his birthday at work ... "All night -- no friends, nothing."