By Rachael Rettner
MyHealthNewsDaily

Smoking marijuana may improve some symptoms of multiple sclerosis, a new study suggests.

Patients with multiple sclerosis in the study had less muscle tightness, also called spasticity, and less pain after they smoked marijuana, compared with after they took a placebo.

Spasticity is a common symptom of multiple sclerosis (MS) and can cause exaggerated reflexes, spasms and problems walking. Existing medications can ease spasticity, but they cause side effects, and not all MS patients are helped by them.

However, patients in the study experienced short-term decreases in their abilities to pay attention and concentrate after they smoked marijuana. Patients also reported feeling "high" after smoking marijuana, and two patients withdrew from the study because they felt uncomfortably high.

More research is needed to confirm the findings and to investigate whether lower doses of marijuana may have similar benefits with fewer adverse effects, said study researcher Dr. Jody Corey-Bloom, professor of neurosciences and director of the Multiple Sclerosis Center at the University of California, San Diego.

The study is published today (May 14) in the Canadian Medical Association Journal.

Improved symptoms

Previous studies have suggested marijuana use may have benefits for MS patients, but most have investigated oral forms of the drug, including mouth sprays and capsules. In addition, most studies have asked patients to report changes in their symptoms, rather than having a researcher objectively assess them.

In the new study, Corey-Bloom and colleagues evaluated 30 MS patients, 19 of whom were female, and more than half of whom needed walking aids.

Participants were randomly assigned to receive treatment with a marijuana cigarette or a placebo cigarette, which did not contain delta-9-tetrahydrocannabinol (THC), the active ingredient of marijuana. Participants smoked a marijuana cigarette once a day for three consecutive days under the supervision of a researcher. Eleven days later, participants repeated the procedure, but this time, they switched treatment groups so that everyone received the marijuana cigarette and placebo at some point in the study. On average, participants smoked four puffs of their cigarettes at each session.

Shortly after each treatment session, the researchers assessed participants with a test specifically designed to measure spasticity.

After smoking marijuana, participants experienced a 30 percent reduction in spasticity, compared with when they smoked the placebo cigarette, Corey-Bloom said.

However, patients did not see improvements in the time it took them to walk 25 feet. And 45 minutes after their sessions, participants experienced a small but significant decrease in scores on tests designed to measure attention and concentration.

Participants were not told whether they recieved a placebo or a true marijuana cigarette, more than half correctly guessed the sessions when they were given marijuana.

Marijuana prescriptions?

The researchers are not advocating marijuana prescriptions for MS patients, Corey-Bloom said. They undertook the study to investigate whether anecdotal reports from MS patients about the benefits of marijuana smoking held up under the scrutiny of science. "I'm not a proponent for marijuana smoking at all," Corey-Bloom said.

Although cannabis may one day be used to treat spasticity in MS patients, delivery through a marijuana cigarette is "probably not the way that it would be done," because of the side effects patients experience, said Dr. Nicholas LaRocca, vice president of health care delivery at the National Multiple Sclerosis Society, who was not involved in the study. "The majority of people with MS experience cognitive changes at some point in their lives," LaRocca said. "We don’t want to add any additional cognitive deficits with treatment," he said.

Researchers are currently investigating other treatments for spasticity, including exercise and Botox injections. "We need to continue to explore all of those possibilities, because any given person with MS may respond better to one [treatment] than another," LaRocca said.

Because many studies have not found a benefit of marijuana for MS patients, and because the new study was small, it's important for researchers to replicate the findings, said Dr. Karen Blitz-Shabbir, director of the Multiple Sclerosis Center at North Shore-Long Island Jewish Health System in Manhasset, N.Y.

Marijuana cigarettes have disadvantages compared with oral forms of the drug, including potential effects on the lungs and problems with administrating a controlled dose, Blitz-Shabbir said.

More from MyHealthNewsDaily:

10 Medical Myths that Just Won't Go Away

Myth or Truth? 7 Ancient Health Wisdoms Explained

Many Young Smokers Also Use Pot

The medical marijuana drug Sativex, which could be approved in the United States in the coming years as a treatment for pain relief, has little potential for abuse, experts say.

The British pharmaceutical company GW Pharmaceuticals is currently testing the drug, which is delivered as a mouth spray and called Sativex, in clinical trials. The company plans to seek U.S. Food and Drug Administration approval for the drug as a treatment for cancer pain when the trials are completed, likely sometime in 2014, a spokesperson for GW Pharmaceuticals told MyHealthNewsDaily.

The active ingredients in Sativex, known as cannabinoids, are derived from the cannabis plant. It is the first marijuana-based drug to be made by extracting the compounds from the plant, rather than synthesizing them. Two other drugs, Marinol and Cesamet, based on synthetic cannabinoids, were approved by the FDA in the 1980s.

Because the drug contains THC, the ingredient primarily responsible for marijuana's "high," it's possible people would use the drug for recreational rather than medical purposes.

"There is no doubt in my mind that there will be people that abuse it," said Dr. Jeffrey Bernstein, director of the Florida Poison Information Center at the University of Miami Miller School of Medicine.

However, because the drug is delivered through ingestion, rather than smoking, it would take much longer to have an effect — at least an hour, compared with the minutes it takes to get high after smoking marijuana, said Margaret Haney, a professor of clinical neurobiology at Columbia University. This means drug users seeking a high would be less likely to abuse it. "Smoking is a really effective way to get a chemical into the brain," Haney said. The mouth spray "is a far safer administration,"she said.

And Marinol and Cesamet, which are also administered orally, have a low rate of abuse. "We don’t see a lot of problems from [those]," Bernstein said.

Not the same high
GW Pharmaceuticals intends to market Sativex in the United States for treatment of cancer pain. The drug is already approved in United Kingdom, Spain, Canada and New Zealand to treat muscle spasms due to multiple sclerosis, according to the company website.

Patients can adjust the dose of Sativex to prevent it from entering the blood too rapidly, allowing them to experience symptom relief without the marijuana high, according to GW Pharmaceuticals.

In addition, while marijuana is a hodgepodge of about 64 different substances, Sativex is composed mainly of two ingredients: THC and another cannabinoid called CBD. The latter component is thought to ameliorate some of the side effects of THC, including the high that marijuana users feel, said Dr. Armando Villarreal, an assistant professor of neurosurgery and pain management at the University of Rochester Medical Center in New York.

And for habitual marijuana users, the cultural and ritualistic practices that go along with smoking pot, such as passing a joint, may be an important part of the experience, Bernstein said. These rituals cannot be replicated with the spray. "A lot of people that smoke marijuana would rather smoke it," he said.

Unlikely overdose
Unlike drugs such as painkillers, which come with a risk of death if people take too much, patients who "overdose" on the marijuana spray would be at little risk for acute health problems, Haney said.

"What could happen is the person could get very uncomfortably intoxicated," Haney said. But in terms of other serious health effects, "there's none that I know of," Haney said.

"Marijuana, in the scheme of things, is a relativity safe drug," Bernstein said. "Even as a smokeable drug of abuse, it's relatively safe…compared to cocaine or heroin."

However, Villarreal noted that for people with psychiatric disorders, smoking marijuana has been shown to make the patients' mental problems worse. It's possible Sativex may also cause this problem in some patients, he said.

Could it help patients?
So far, the studies that have been conducted do not provide enough evidence to say Sativex is effective in improving pain symptoms, Villarreal said.

Sativex has mainly been tested as a drug to treat pain caused by damaged nerves. If the drug is approved by the FDA, Villarreal speculated, its use could be restricted to certain pain patients. Those with cancer pain that is not caused by damaged nerves may not be candidates for the drug, Villarreal said.

About 1 in 11 people who try pot end up addicted to it, Haney said. It would be interesting to study whether Sativex could help people in dependent marijuana users quit the drug, she said.

• How Marijuana May Drive the Brain into Psychosis
• 7 Side Effects of Cancer Treatment, and How to Cope with Them
• 10 Do's and Don'ts to Reduce Your Risk of Cancer

Smoking a joint a day for up to seven years didn't cause a reduction in lung capacity, a new study shows.

Periodically smoking marijuana doesn't appear to hurt lung capacity, the largest study ever conducted on pot smokers has found.

Even though most marijuana smokers tend to inhale deeply and hold the smoke in for as long as they can before exhaling, the lung capacity didn't deteriorate even among those who smoked a joint a day for seven years or once a week for 20 years, according to the study published Tuesday in JAMA, the journal of the American Medical Association.

In recent years, studies on marijuana smoking and its effects on lung function have been contradictory. While most studies have shown no effects on the lungs from smoking cannabis, others have shown adverse effects, and still others have shown improvement in lung function. Researchers at the University of California, San Francisco, and University of Alabama at Birmingham knew tobacco smoking causes lung damage and leads to respiratory issues such as chronic obstructive pulmonary disease (COPD), but they wanted to be clear whether smoking marijuana, had similar effects.

They measured lung function multiple times in more than 5,100 men and women during a 20-year period. In fact, the research shows, some people who regularly smoke marijuana can have a slight improvement in lung function.

Experts say that people shouldn’t simply take the news as green light to get high, but should also consider other factors.

“Marijuana is a complicated substance, and for people who are thinking about what they’ve done in the past or are thinking about using marijuana or believing it can help medically, their decision should not be based on lung consideration,” says study co-author Dr. Stefan Kertesz, a researcher and primary care doctor at University of Alabama at Birmingham and the Birmingham VA Medical Center.

“It’s not a decision about lung health, it’s all the other issues: the risk of addiction, an increase in the chance of having accidents and social functioning.”

Researchers reached their findings by using data from the Coronary Artery Risk Development in Young Adults, collecting repeated measurements of lung function and smoking from March 1985 to August 2006.  More than half of the participants, or 54 percent, said they were current marijuana smokers, cigarette smokers or both when the study began. The average marijuana use was only a joint or two a few times a month — typical for U.S. marijuana users, Kertesz said.

The authors calculated the effects of tobacco and marijuana separately, both in people who used only one or the other, and in people who used both. They also considered other factors that could influence lung function, including air pollution in cities studied.

The analyses showed pot didn't appear to harm lung function, but cigarettes did. Cigarette smokers' test scores worsened steadily during the study.

Researchers measured how well participants could blow air in and out. A healthy adult can exhale about a gallon of air in one second. Although their study focused on lighter smokers, they found some people who smoked more than a joint a day for seven years, could exhale slightly more air than that.

Kertesz says that extra strength may come from the habit of deeply inhaling, holding and slowly exhaling marijuana smoke.

“It’s a tiny increase; it’s not a big increase to lung health,” he says. “So be careful not to say that, ‘Oh, wow! Lungs work better on marijuana.’ That would be totally inaccurate.” 

Authors say there weren't enough heavy users (those who smoked two or more joints a day) among those in the study to draw firm conclusions on that group.

Dr. Donald Tashkin, who has studied the relationship between marijuana smoking and lung function for more than 30 years as a professor of medicine at UCLA, says the study confirms what other research has also concluded.

“This is a well-done study involving more subjects than in the past,” says Tashkin, who is not affiliated with the new study. “The public should take away it’s a confirmatory study, but larger and longer than previous studies demonstrating, once again, that smoking marijuana does not impair lung function, unlike tobacco.”

Tashkin says scientists have a theory that lung capacity is not affected in marijuana smokers because the chemical THC in marijuana has immunosuppressant properties that interfere with the development of respiratory issues such as COPD. He says this indicates there will be lower rates of COPD, but marijuana smokers are still at risk for chronic bronchitis, which means they tend to have increased cough and mucus. The study didn't look at the risk of lung cancer.

And Tashkin cautions about drawing overall conclusions from the new work: “We’re only talking about one end point. We’re not looking at lung cancer, chronic bronchitis symptoms. We are not looking at other effects, behavioral effects. We are looking at lung function.”

The Associated Press contributed to this report.

Does this change how you feel about pot use? Tell us on Facebook.

More from Vitals:

All that stress is shrinking your brain, study finds

Donating your body to science? No one wants a chubby corpse

Another reason dogs rule: They know what you're thinking

Risk of heart attack jumps 21 times after loved one's death

By Stephanie Pappas, LiveScience

In science, it's not enough to think something is so. Researchers must show that what  we believe to be true is in fact true, proven through statistically significant and reproducible results. Questioning assumptions is, after all, what science is about.

Nonetheless, some studies really take the cake in the "duh" department, discovering  things that were already obvious. Here are findings from this year that should come as little surprise.

1. Unsafe sex is more likely after drinking

Drinking too much alcohol can impair decision-making. And a study out this year drove this point home: Canadian researchers, reporting results that will be published in January in the journal Addiction, said they ran 12 studies looking at the link between blood alcohol and the likelihood of agreeing to use a condom during sexual intercourse. The more alcohol in a person's system (yes, the drunker they were), the more likely they were to throw caution to the wind and ditch safe sex. Specifically, for every 0.1-milligram-per-milliliter increase in study participants' blood alcohol levels, there was a 5 percent increased likelihood of having unprotected sex.

2. Men appear confident by suppressing fear, pain and empathy

When mixed martial arts fighters need to show off masculine strength and confidence, they suppress fear, empathy, pain and shame.

Yeah, not too shocking: that tamping down those emotions might make someone seem more formidable. But the research, published in December in the journal Social Psychology Quarterly, was aimed at understanding how men manage their emotions and expectations of manhood.

"Managing emotional manhood, whether it occurs in a locker room or board room, at home or the Oval Office, likely plays a key role in maintaining unequal social arrangements," study author Christian Vaccaro of Indiana University of Pennsylvania said in a statement.

3. Smoking pot and driving isn't safe

Who knew, getting behind the wheel while high could be trouble? According to a study published in October in the journal Epidemiologic Reviews, marijuana use increases the risk of car crashes. People who took to the road within three hours of smoking pot, as well as those who tested positive for the drug, were more than twice as likely as other drivers to be involved in a car crash. And that risk increased for those who smoked more frequently and those showing a higher level of the drug in their urine.

4. Pigs love mud

Turns out pigs aren't just putting on a show when they haul butt around their muddy quarters, diving into the muck. They actually like it. While mud baths keep pigs cool, a review of research reported in 2011 found wallowing may also be a swine sign of well-being. While the review found the strongest reason noted in the past studies for wallowing was to keep cool, the pigs kept it up through winter months.

5. Fashion magazines glorify youth

Surprise, surprise: Fashion mags portray women over 40 sparingly, if at all. Young celebrities and models dominate the pages of these publications, even ones targeted at older age groups. For example, researchers reported in April in the Journal of Aging Studies, that 22 percent of the reader base of Essence is older than 50, but only 9 percent of the women in its pages were even older than 40. Vogue featured only one woman over 40 on its covers in 2010: Halle Berry (then 43).

6. People with generous partners have happy marriages

In the realm of unsurprising marriage advice, researchers found this year that generous marriages are happy marriages. Couples with spouses who offer back rubs and other seemingly selfless acts are happier with their relationships than people who report low amounts of generosity in their marriages, according to researchers with the National Marriage Project.

Half of women and nearly half (46 percent) of men who reported above-average generosity in their marriages described themselves as "very happy" with their relationships. In comparison, only 14 percent of people with low levels of generosity in their marriages said the same.

7. Parents don't think their kids are doing drugs

Smoking pot and drinking? Not my daughter! Parents are in denial about their own children's bad habits, according to poll data released in September by the University of Michigan's C.S. Mott Children's Hospital. That study found that while most parents believe at least 60 percent of 10th-graders drink alcohol, only 10 percent thought their own teen did. 

8. People aren't doing anything in particular on the Internet

Anyone who has ever gone down an Internet black hole, only to emerge hours (and dozens of Wikipedia articles) later, will be less than shocked at the revelation that online is the place to go for mindless entertainment. According to a Pew Research report released in December, 53 percent of people ages 18 to 29 get online at least once on any given day just to pass the time. Using the Internet to goof off isn't limited just to the young, either: Fifty-eight percent of all adults said they sometimes get on the Internet for no reason other than casual entertainment.

9. Restricting driver's licenses decreases teen fatalities

Graduated licenses, which allow teens more freedom behind the wheel as they gain driving experience, save lives. Researchers at the Institute for Research and Evaluation (PIRE) reported in November that fatal automobile crash rates among 16- and 17-year-olds fell 8 percent to 14 percent in states that enacted graduated-licensing laws. Restrictions such as limits on the number of passengers a teen can ferry around and rules against night driving decreased fatal crashes by 13 percent and 9 percent, respectively. Practice (and a little more maturity) makes perfect, it seems.

10. Most shoppers ignore nutrition labels

Calories, cholesterol, sugar … yawn. A study published in October found that grocery shoppers pay little attention to the information on nutrition labels. Even shoppers who say they "almost always" read nutrition information aren't likely to take in much information in a real-world shopping environment, the research found. Using an eye-tracking device on study volunteers, researchers found that only about 1 percent looked at information about total fat, trans fat, sugar and serving size on nearly all labels, even though between 20 percent and 31 percent of people said they looked at each of those categories when they shopped. Anything low on the label is particularly unlikely to get attention. The study found that the average consumer doesn't make it past the fifth line.

11. Presidents outlive their contemporaries

U.S. presidents tend to live as long or longer than their contemporaries, according to research published Dec. 7 in the Journal of the American Medical Association. Sure, being chief executive is stressful (and eight have died in office, four by assassination), but it turns out the top job in the country comes with perks: great medical care, for example. Presidents also tend to be well-off and well-educated, according to lead researcher S. Jay Olshansky, a professor of public health at the University of Illinois at Chicago. Unsurprisingly, money and knowledge tend to buy health and longevity.

• Doh! Top Science Journal Retractions of 2011
• Top 10 Wacky Animal Stories of 2011
• 6 (Other) Great Things Sex Can Do For You