Teenage boys are much more prone to development of psychotic disorders up to the age of 16. Some researchers have insisted that marijuana use in teenage males causes schizophrenia. A new study conducted by Dr. Tomas Paus, Professor and Chair in Population Neuroscience at Baycrest with the University of Toronto, and colleagues has found that marijuana use does not cause schizophrenia in young men but may accelerate processes that are already genetically in play in the development of schizophrenia and other psychotic disorders.

Two new studies out today in JAMA Psychiatry highlight the persistent questions about how cannabis might affect brain development.

In one study, twins had similar brain volume even when one used recreational marijuana and the other didn't. But in the second study, high-risk male teens who used marijuana did have changes in brain volume.

Experts agree that much remains unknown and the new findings just "scratch the surface."

"We do not know nearly enough about effects of cannabis on the brain, especially the developing brain," said Dr. David Goldman of the National Institute on Alcohol Abuse and Alcoholism in Rockville, Maryland, in email to Reuters Health.

BOULDER, Colorado -- Holly Alberti-Evans considers herself among Colorado’s marijuana business success stories. Healthy Headie Lifestyle, the in-home direct sales company for cannabis products she founded with her husband, Steve Evans, is growing, with a busy office in Boulder and an expanding team of independent distributors who demonstrate vaporizers to those Alberti-Evans calls the “canna-curious” in the privacy of their homes. (Hosts provide their own marijuana if they want to take the devices for a full test drive.) What’s more, Alberti-Evans is constantly fielding calls from those wanting to invest in the enterprise.

“We have had an overwhelming response,” says Alberti-Evans. “There is absolute excitement around our business model and everyone wants to participate.”

Iraq combat veteran Chris Whittenburg credits cannabis with saving his marriage and ending the PTSD-spawned anger and anxiety that were destroying his life.

You may imagine that with its liberal laws and Amsterdam’s cannabis coffee shops, the Netherlands would top a poll of cannabis use. But a series of maps has revealed that in fact Iceland smokes the most weed - with the Netherlands not even making the top five. The US tops the chart for prescription drug abuse as well as cocaine, while Norway consumes the most alcohol.

When I was a teenager, I bought pot whenever I wanted. As an adult, I worked to keep pot out of the hands of anyone under 21, and to make cannabis use as safe as possible for anyone 21 and over.

I've been a part of Colorado's legal cannabis industry since regulation was approved by our state's citizens in 2012. Since then, I've seen firsthand that two of the biggest public concerns -- that regulation makes it easier for children to access cannabis, and that regulation leads to a rapid increase in cannabis users -- simply haven't happened.

CINCINNATI -- He was once responsible for arresting pot users and dealers, now a former Cincinnati police captain is advocating for legal marijuana.

The pro-pot group ResponsibleOhio is launching a new ad campaign featuring retired Capt. Howard Rahtz.

In the ad, Rahtz talks about seeing the drug problem firsthand and that in his opinion, Ohio’s war on drugs doesn’t work.

“Simply put, they don’t work,” Rahtz said.

He goes on to call out the cost of the prohibition to Ohio alone and that “it’s time for marijuana reform so law enforcement can focus on cracking down on real criminals.”

Drive an hour east of Portland, Oregon, through the stunning Columbia River gorge, and you'll arrive in the idyllic town of Hood River. Tourists come to windsurf and fly kites in the stiff breeze that blows off the river, and to tour the "fruit loop," a circuit of wineries and fruit vendors supplied by the area's abundant orchards.

But there are no tours — at least not yet — that introduce visitors to the region's other signature crop: marijuana.

SAN FRANCISCO — The likelihood that California voters will be asked to legalize recreational marijuana next year is prompting lawmakers to make a serious run at reining in the state's vast medical marijuana industry — a job they have deferred for nearly two decades.

A pair of bills pending in the California Legislature would create the first statewide regulations for medical marijuana growers, manufacturers of pot-infused products, and distributors such as storefront dispensaries and delivery services.

California authorized marijuana use for health purposes with a 1996 ballot measure that allows doctors to recommend the drug for any ailment, deliberately leaving the specifics for how it should be produced and sold for another day.

Without reconciliation of banking laws at a federal level, local businesses, such as those popping up in Alaska, will need security to handle cash.

Like a gold rush, Alaska's upcoming green rush will bring stacks of specie and currency, along with a version of the Pinkertons to guard the loot.

Federal banking laws prohibit federally- or state-chartered banks and credit unions from accepting marijuana deposits or giving marijuana loans. The disparity between federal law and states that have legalized the product creates a unique security risk, as it consigns every cannabis grower, retailer, and broker to a cash-only business model ripe for theft or robbery. Alaska is catching on to a trend of cannabis business security that is rapidly growing in the Lower 48.