The former child star was sitting in his car Tuesday outside of his L.A. home sucking on a fully inflated balloon. In one of the photos, you can see a cannister of some sort -- which resembles a typical nitrous oxide container.

Of course, huffing nitrous is a dangerous but popular method of getting high -- a few seconds of euphoria and head rush -- without using hard drugs.

BTW ... this is not Drake's first rodeo with nitrous oxide -- he was pictured doing the exact same thing back in December, and, in that instance his young son was in the car too.

And yes, inhaling nitrous oxide without a medical professional's supervision or guidance is, indeed, bad for one's health.

As we reported ... Drake's clearly been going through it of late. He told Twitter users last week that he was contemplating suicide after the trolling and attacks over his child endangerment conviction in 2021 -- which has led to people labeling him a "pedophile."

On top of that ... his wife filed for divorce just a couple days prior, this after he was reported missing in Florida -- only to pop up on the radar again in what turned out be a false alarm.

We know Drake has been thrust into a child custody battle with his now-estranged wife -- and, apparently, it's gotten so ugly behind the scenes ... he's been sending scary messages to his family that made them worry for his safety and his life.

The guy's had a lot of ups and downs in recent years -- everything from a choppy music career to even more legal issues like a DUI bust and bankruptcy.

As we reported, family members called police a couple weeks ago, because they were so worried about Drake. These images won't ease those concerns.