Kanye West Hospitalized, Handcuffed in Ambulance

Kanye West has been taken to UCLA Medical Center for psychiatric evaluation.

According to law enforcement sources ... cops responded to a call for a welfare check on Kanye around 1:20 PM PT. He was at his trainer Harley Pasternak's home at the time and was "acting erratically."

We're told police called L.A. Fire, and by the time paramedics arrived Kanye was calmer ... but still resistant to going to the hospital. We're told everyone -- his management and law enforcement -- convinced him it was best he go. Law enforcement sources tell us Kanye was handcuffed to a gurney during transport to the hospital ... as standard protocol.

We got Pasternak outside his house late Monday evening. If he knows how Kanye's doing, he's not saying much.

Sources connected to Kanye tell us he was getting checked out by one of his doctors for severe sleep deprivation while he was at Pasternak's place ... and someone decided to call police.

The hospitalization comes on the heels of Kanye abruptly cancelling the remainder of his Saint Pablo Tour, and launching into a verbal attack on Jay Z and Beyonce.

As we told you, Kim Kardashian flew to NYC early Monday for her first public event since the Paris robbery ... but she's now officially bailed. It's a good bet she's wheels up for L.A.