- A crash is more serious driving under the influence of alcohol or marijuana
- Marijuana and alcohol increase sexual desire but lower physical ability
- Excess beer gives you a bigger belly, but pot smokers are skinnier, studies show
(CNN)As more states legalize medical and even recreational marijuana, more communities are being forced to ask a key question about pot: how bad is it, really? Even the President has weighed in:
"As has been well-documented, I smoked pot as a kid, and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life," President Barack Obama told New Yorker Editor David Remnick. "I don't think it is more dangerous than alcohol."
Alcohol is the most commonly used addictive substance in the United States, according to the National Institute on Alcohol Abuse and Alcoholism. It's legal for those 21 and older. Only about 22% of adult women and 11% of adult men are lifetime alcohol abstainers.
Marijuana, on the other hand, is classified by the Drug Enforcement Agency as a Schedule 1 substance -- the same category as heroin, LSD and Ecstasy -- and is illegal in almost all states for recreational use. As such, comprehensive data on the drug's use and misuse in the United States is limited.
Here's what we do know:
Alcohol's addictive qualities are well-documented. Approximately 17.6 million people, or one in every 12 adults, suffer from alcohol abuse or dependence, according to the NIAAA. Alcoholics in withdrawal can suffer from anxiety and depression, headaches, insomnia, nausea, fever and even seizures.
The addictive qualities of marijuana are not yet fully understood. The National Institute on Drug Abuse estimates 9% of people who use marijuana will become addicted to it. For comparison's sake, cocaine hooks about 20% of those who use it.
"There is clear evidence that in some people, marijuana use can lead to withdrawal symptoms, including insomnia, anxiety and nausea," CNN Chief Medical Correspondent Dr. Sanjay Gupta wrote in his story, "Why I changed my mind on weed," referring to medical marijuana.
"Even considering this, it is hard to make a case that it has a high potential for abuse. The physical symptoms of marijuana addiction are nothing like those of the other drugs I've mentioned."
Driving under the influence
Every hour, one person is killed and 20 are injured in crashes involving a drunken driver, according to the National Transportation Safety Board.
A recent study found that even slightly "buzzed" drivers -- drivers with a blood alcohol level of 0.01%, meaning someone who has had even one drink -- are 46% more likely to be blamed for a crash when they collide with a sober driver.
The jury is still out on the impact of people who use marijuana and drive. Early studies showed marijuana had a slight impact on the psychomotor skills needed to drive, but these studies were seen as limited since they were done in lab situations.
A recent study review published in the British Medical Journal found people who used marijuana within three hours of driving were nearly twice as likely to cause a crash as sober drivers. People who use marijuana in combination with other drugs or alcohol also pose an increased crash risk, research suggests.
Munchies and beer bellies
It seems logical to think that alcohol would make you gain weight. One shot of liquor has about 100 calories; a beer usually contains around 150. Plus, alcohol lowers your inhibitions, encouraging you to binge on pizza and nachos.
As for marijuana, even cops know it gives you the munchies.
Yet some studies on whether alcohol or marijuana really cause weight gain have been contradictory.
One study of more than 19,000 women showed those who drank alcohol in moderation actually weighed less than those who didn't over 12 years. Others have linked obesity and alcoholism; frequent drinkers seem to be more at risk.
Marijuana smokers seem to be skinnier than those who don't smoke. A study published in the American Journal of Epidemiology found that rates of obesity are lower by roughly a third in people who smoke pot at least three times a week, compared with those who don't use marijuana at all.
The desire's there...
Drinking reduces your inhibitions and can certainly make you feel more relaxed in social situations. But those lower inhibitions can also lead you to engage in risky sexual behavior, studies show. Unprotected sex can increase your risk of catching a sexually transmitted disease or infection and increase your chances for an unplanned pregnancy.
And while serving as a social lubricant, drinking alcohol actually leaves you dehydrated. The body needs a certain level of hydration and blood flow for sexual arousal. Drinking too much makes it difficult for men to have an erection and for women to feel pleasure from natural lubrication, studies have shown.
Marijuana may have a similar impact as alcohol in lowering your inhibitions and reducing your anxiety, but some studies have shown men have a harder time finding pleasure during sex under the influence.
A couple of studies found that men who use marijuana regularly had more problems with erectile dysfunction and needed medication to counteract that side effect. There are no similar studies that look at women's sexual satisfaction under the influence of pot.
Long-term health risks
Over time, drinking can lead to liver disease, neurological problems, certain psychiatric issues and may increase your risk of several types of cancer.
Smoking marijuana is more dangerous than smoking cigarettes, experts say. The tar in joints contains a much higher concentration of the chemicals linked to lung cancer compared with tobacco tar. And smoking marijuana deposits four times more tar in the lungs than smoking an equivalent amount of tobacco, according to the National Institute on Drug Abuse.
High doses of marijuana can also cause temporary psychotic reactions, such as hallucinations and paranoia in some people. Younger people with a family history of schizophrenia are at a higher risk of developing the disorder after using marijuana, seven studies showed.
About 88,000 Americans die each year because of excessive alcohol use, according to the CDC. Nearly half of those deaths are from chronic alcohol use -- liver failure, for example -- while the other half are attributable to acute situations, such as alcohol poisoning or a drunken driving accident. There are an average of 1,600 alcohol poisoning deaths, or overdoses, each year.
Weed can kill you too, as this drug dealer showed.
In all seriousness, marijuana affects your reflexes, hindering your motor skills. So marijuana-related car fatalities are not unheard of.
And one study found marijuana users have a 4.8-fold increase in risk of a heart attack during the first hour after smoking because of the drug's effect on your heart rate.
That said, scientists believe that a marijuana overdose is highly unlikely. One study found it was safe for animals to consume about 30% of their body weight in cannabis without overdosing; that's the equivalent of a 160-pound person eating 48 pounds of weed at one time.