Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Estrogen increases cannabis sensitivity


Females more likely to see tolerance and addiction while males get the munchies

Smoking today's concentrated pot might be risky business for women, according to new research from Washington State University. The study is the first to demonstrate sex differences in the development of tolerance to THC.

Psychology professor Rebecca Craft showed that, thanks to their estrogen levels, female rats are at least 30 percent more sensitive than males to the pain-relieving qualities of THC—the key active ingredient in cannabis. Females also develop tolerance to THC more quickly. These sensitivities could increase vulnerability to negative side effects like anxiety, paranoia and addiction.

The findings were recently published in the journal Drug and Alcohol Dependence.

The research was supported by a grant from the National Institute on Drug Abuse.

Many unknowns

Craft said other researchers, like Margaret Haney at the Columbia University Medical Center, have shown that women are more susceptible to cannabis abuse and dependence than men. Haney has documented a cannabis withdrawal syndrome of irritability, sleep disruption and decreased food intake that Craft said tends to be more severe in women. Women also have a greater tendency to relapse when trying to stop using the drug.

Despite the known differences in how marijuana affects the sexes, Craft said most THC tolerance studies have been done on males.

With recent legalization of recreational marijuana in Washington and Colorado—and many more states allowing medicinal use—Craft said there is greater burden on researchers to understand the effects of cannabis and ferret out differences between males and females.

She said the "munchie effect" appears to be the only THC reaction where males show more sensitivity than females. Studies in California found that THC stimulated the appetites of male animals more than those of females.

Cannabis complex

The marijuana plant contains more than 60 compounds known as cannabinoids. THC, or tetrahydrocannabinol, is the psychoactive ingredient behind the characteristic mental high. Cannabidiol and cannabinol occur in smaller amounts but may be useful for medical purposes.

All three compounds are present in the most common species of marijuana, Cannabis sativa and C. indica, but in varying proportions.

Craft said most medical marijuana patients prefer a balance between the cannabinoids. But when it comes to recreational pot, selective breeding has resulted in THC concentrations double or triple those seen in the 1960s and 70s.

"Marijuana is very different than it was 40 years ago," she said. "It's much higher in THC and lower in cannabidiol, so a little bit goes a very long way.

"We're more likely to see negative side effects today like anxiety, confusion, panic attacks, hallucinations or extreme paranoia," she said. "And women are at higher risk."

One of the few female studies

Most clinical drug trials have been conducted on men due to their more stable hormonal profile. Despite the recommendation of the National Institutes of Health in 1993 to include more women in studies or give good reasons not to, many researchers still avoid dealing with the hormone swings inherent in a woman's biology.

But Craft has been studying drug sensitivities in females for years.

Working with rats in her laboratory, Craft said she and her team "routinely manipulate hormones and follow females across their cycles to see if their drug sensitivities change along with their hormones. And they do…very frequently." Estrogen is the culprit.

"What we're finding with THC is that you get a very clear spike in drug sensitivity right when the females are ovulating - right when their estrogen levels have peaked and are coming down," she said.

Surprise finding

In the current study, Craft and her team examined the pain relieving effects of THC in male and female rats. After 10 days of treatment, tolerance to THC was shown to be significantly greater in females than males.

Tolerance occurs when the rat "adapts" to THC so that larger doses are required to produce the same pain-relieving effects initially seen with the first dose.

Because Craft already knew that females were more sensitive to THC, she adjusted their doses to be 30 percent lower than doses for males. The females still developed more tolerance.

"This is the lowest dose anyone has ever used to induce tolerance," she said.

The team also found that a low dose of THC did not disrupt the reproductive cycle in female rats, something that has been under debate and, Craft said, needs more study.

Medical marijuana

Hoping to gain greater insights into marijuana's medical potential, Craft and her team are also studying the effects of cannabidiol, which can counter some of THC's negative side effects.

The THC and cannabidiol studies will be extended to include chronic types of pain typically seen in people who request medical marijuana—such as those with debilitating back or joint pain, cancer, Crohn's disease, multiple sclerosis, severe muscle spasms and more.

"These people have pain that lasts for months or years," Craft said. "Tolerance develops differently and sometimes you get a lot less tolerance to a drug when people are in chronic pain."

Craft uses a standard research formulation of delta-9-THC for her studies and is approved by the U.S. Drug Enforcement Administration to work with Schedule I drugs such as cannabis.

Rebecca Craft | Eurek Alert!
Further information:

Further reports about: Drug Estrogen Medical THC differences effects female females marijuana pain tolerance

More articles from Health and Medicine:

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>