University at Albany psychology professor Mitchell Earleywine and Thomas F. Denson, of the University of Southern California, recently completed a study finding that people who smoke marijuana are less depressed than those who never smoke.

The respondents were in three categories: those who have never smoked, daily smokers and weekly smokers. Both daily and regular uses said they were less depressed.

The online study, which involved 4,400 people, was supported by a grant from the Marijuana Policy Project, a group that supports legalizing and regulating the drug. The findings are to be published in the journal Addictive Behaviors.

The findings surprised Earleywine.

"I expected that depression would be even, that the groups wouldn't differ at all," Earleywine said. "I never thought the users would be less depressed."

Earleywine co-authored a study in September showing that marijuana use among teenagers falls in states that allow medical marijuana. And, indeed, his latest work flies in the face of other work that has linked marijuana to depression.

He cautioned that his research doesn't mean that weed will make troubles go away. Chances are, the type of person who smokes marijuana just happens to be the type of person who doesn't depress easily.

"They may just have a more mellow attitude about everything," Earleywine said. "So if they're less concerned about cannabis, they're probably less concerned about other things."

The study did find that people who use marijuana for medical reasons are more likely to be depressed than other smokers -- not surprising, perhaps, given that they're smoking because they're sick. They were less depressed overall than nonsmokers, though.

Earleywine said his research is clear evidence that marijuana doesn't lead to depression.

For anybody out there still tempted to light up to stave off depression, though, Earleywine suggested they shouldn't.

Please also read: Long Term Exposure To Cannabis