Monica Seles, Mick Jagger, and Ariana Grande all have been diagnosed with post-traumatic stress disorder (PTSD).

Tennis great Seles was stabbed during a match by a crazed fan in 1993; Jagger's long-term partner L'Wren Scott committed suicide; and a suicide bomber at Grande's 2017 concert in Manchester, England, killed 22 people.

In short, PTSD can kick in after any kind of trauma, causing disturbing thoughts and feelings, flashbacks or nightmares, and profound sadness, fear, or anger. Clearly, it is no laughing matter.

But don’t tell that to researchers from the University of Chicago Medicine and Stanford University Medical School. In a small pilot study of three veterans ages 31 to 46 with PTSD, the researchers found that a one-hour dose of 50% nitrous oxide — aka laughing gas — and 50% oxygen can ease symptoms of the condition.

For one of the volunteers, improvement lasted for a full week; for a second, symptoms returned gradually over the course of a week; and for the third, improvements lasted from two hours after treatment until the next day.

Nitrous oxide seems to work by blocking the same receptor (NMDA) that the recently approved antidepressant medicine ketamine blocks.

Treatments including trauma-focused psychotherapies, cognitive behavioral therapy, antidepressants and other medications, medical marijuana, and physical exercise are often hit-or-miss with PTSD. And it's estimated that around 30% of those diagnosed never recover.

So the addition of this new treatment option — with no significant side effects — should put a smile on the face of those who treat and those who contend with PTSD.