One thing is for sure: with the spread of cannabis legalization across the United States, people in those states that voted for marijuana sales are going to be laughing a lot more.

You know it’s true. But why?

Anyone who has ever tried marijuana knows one of the happy effects is that things seem, well, more funny. Sometimes much more funny. Sure, cannabis can elevate your mood, as can other stimulants, but what about those uncontrollable gusts of laughter?

At this point, no one is 100 percent sure why marijuana promotes laughter, although several possible causes have been isolated. Obviously it involves, at least in part, the effects on you from THC, the active ingredient in marijuana that gives you that “high” feeling.

Cannabis Making You Laugh: Increased Blood Flow

One study, published in the journal of Experimental and Clinical Psychopharmacology, found that THC activates more blood flow to the right frontal and left temporal lobes as well as the cerebellum.  The first two are associated with laughter.

An increased blood flow to those regions means more activity, and more activity may mean more chance of laughter.

Studies also have shown that THC binds to the receptors in your brain that send and receive electrical impulses, giving you that “high” feeling and elevating your mood. How elevated? Well, some studies have shown that the affect is strong enough to help fight off anxiety and even helped those who suffer from depression.

Laughter Is Contagious

While increased blood flow and affected brain receptors can make a change in your tendency to get happy and laugh, another factor is the simple fact that laughter is contagious.

Most people use marijuana in a social setting, meaning that when a person finds something funny, you likely will find it funny, as well. This is true under any circumstance, but since you likely are in a better mood than usual under the influence of cannabis, that laughter is likely to be more uninhibited than usual.

Why Laughter Is Good

As pointed out in “The Healing Magic of Cannabis,” a book by Beverly Potter and Dan Joy, all this laughter proves a good thing.

“Laughter heals,” the pair wrote. “It promotes and strengthens communion with others, refreshes perspective to make it easier to deal with difficult situations, and even fosters health on a physical level.”

Potter and Joy say that cannabis provides users with a “refreshed perspective,” allowing them to distance themselves from their problems and see them in a new, often more light-hearted, way. It also reduces the fear of looking foolish or embarrassing yourself in front of others.

This is especially beneficial for those with a chronic medical condition, who often withdraw and become reclusive when confronted with their condition and fear the reaction of other people. Marijuana, at least temporarily, can help. “Cannabis lightens such heavy attitudes and promotes conviviality, making us more likely to seek the company of others,” the authors wrote.

So, while the jury is still out on exactly why cannabis makes you laugh, the bottom line is that it’s a good thing that it does. As researchers continue to look for the cause, you can feel good about enjoying the effect.