While hitting the bong might make it harder for you to remember where you put your keys, it may make it easier for grandma to find hers, according to a new study.

The study, published in the journal Nature Medicine, found that the psychoactive compound in marijuana, THC, may reverse brain aging and restore learning ability when given in consistent, low doses. Andreas Zimmer, who led the study with scientists from the University of Bonn in Germany, noticed that genetic mutations in mice that prevented their endocannabinoid systems from working property aged faster and exhibited more cognitive decline. What, Zimmer wondered, would happen if the opposite had happened and the mice's endocannabinoid systems were stimulated?

Zimmer's team then took middle-aged and elderly mice and gave them regular doses of low amounts of THC before testing their cognitive performance against that of young mice. They performed just as well and the research further indicated the stoned mice showed evidence of an increase in brain cell connections in the hippocampus, the part of the medial temporal lobe involved in emotions, learning and memory formation.

"We repeated these experiments many times," Zimmer told New Scientist. "It's a very robust and profound effect."

While the research is obviously in its infancy and there's no telling whether it would carry over to human patients, the hope is it may eventually lead to new treatments for dementia and Alzheimer's. And it's not the first to indicate cannabis could help battle cognitive decline.

More than a decade ago, in 2006, Kim Janda, a chemistry professor at Scripps Research Institute, published a study showing that THC inhibits cerebral amyloid deposits from forming in the walls of blood vessels in the central nervous system, diminishing cognitive functions. Janda's study found that THC seems more effective than other drugs in fighting the forming of amyloid deposits.

With 5.3 million Americans living with Alzheimer's disease, the sixth leading cause of death in America, according to the Centers for Disease Control — and 16 million expected to be diagnosed by 2050 — it's fair to ask why researchers aren't falling all over themselves to study this. Well, that stems back to the federal Controlled Substances Act and its classification of marijuana as a Schedule 1 narcotic meaning that, in federal eyes, it has no medical value, making it extremely difficult for researchers to get waivers to do controlled studies within the United States.

But — with research like this, as well as other studies linking marijuana to everything from reduced rates of opioid abuse to lower instances of diabetes — isn't it time for Congress to green light research? What could be holding it back?

Well, there's surely still the Reefer Madness sect — with one Jefferson Beauregard Sessions leading the charge — but they seem to be grossly outnumbered. After all, Congress has included a prohibition against the justice department cracking down on state legal weed in years' worth of budget bills.

There's an old adage in both journalism and criminal investigations: Follow the money. To that end, a report released this week by New Frontier Data found that if the federal government legalized medical marijuana for ailments like chronic pain, seizures and anxiety, it could result in a more than $4 billion annual loss for the U.S. pharmaceutical industry.

What does that have to do with Congress? Glad you asked. According to Opensecrets.org, the average congressional candidate received more than $30,000 in campaign contributions from the pharmaceutical industry in 2016. And that's to say nothing of the roughly $250 million the industry spent on lobbying efforts last year.

Hate to be cynical, but it seems Big Cannabis has some work to do if it wants a seat at the table. And if you want to help grandma find her car keys, you might have to help find her wallet first.

Thadeus Greenson is the Journal's news editor. Reach him at 442-1400, extension 321, or [email protected]. Follow him on Twitter @thadeusgreenson.