The sad news of actor and comedian Robin Williams taking his own life on Monday has re-opened a national conversation about depression and suicide.

One psychology professor at UNC has advice for people affected by those issues.

“Somebody who is thinking about suicide or might be experiencing depression, and could be at risk for suicide absolutely must receive professional help.”

That comes from Dr. Mitch Prinstein, a professor of clinical psychology at UNC.

Like millions of others around the world, he was deeply saddened to learn of Robin Williams’ suicide on Monday.

“It’s so sad that depression can really cloud one’s thoughts and feelings so much that they can’t recognize how much support and love there is for them in the world,” said Prinstein.

Williams battled depression for decades, and had recently checked into the Hazeldon Addiction Treatment Center in Minnesota, to avoid relapsing into substance abuse.

Prinstein, whose research focus is on the predictors of adolescent depression and suicide, stressed that depression and substance abuse are two warning signs that people should be very aware of in friends and loved ones at risk.

And there are others.

“Someone who has threatened suicide, made a plan for suicide, or previously attempted suicide, is also at extremely high risk for a future attempt.”

He added that people who start giving away belongings, or seem to be lifting suddenly out of a deep depression may be at risk for a suicide attempt.

But not everyone plans out a suicide attempt in advance, he warns.

“Some people do attempt suicide after an acute stressor,” said Prinstein, “sometimes just minutes or hours after a stressor.”

That’s especially true when substance abuse is involved.

Obviously, then, it’s impossible to know exactly when someone may attempt suicide. Prinstein and other mental health professionals urge those suffering from suicidal thoughts to reach out for help.

The most important advice is: Try to put aside any perceived stigma about mental health problems, and please, talk to somebody about it.

“Not talking about suicide is dangerous,” said Prinstein. “And talking about suicide does not make people more likely to do it. In fact, it will make people less likely to attempt. So, people – please – must talk about suicide and depression openly.”

If you’re depressed and having thoughts of harming yourself, please call Emergency Crisis Services at 1-800-233-6834, available seven days a week, 24 hours a day.