Dear Doctor: I see that psilocybin mushrooms -- what we used to call magic mushrooms -- are being studied now as a possible treatment for post-traumatic stress disorder and depression. I've struggled with severe depression my whole life. Would it be risky for me to give magic mushrooms a try?

Dear Reader: In a word -- yes. Although emerging research into the potential benefits of psilocybin for people with depression and anxiety disorders is encouraging and intriguing, we absolutely recommend against self-experimentation.

First and foremost, psilocybin, which is the compound in certain mushrooms that gives them their hallucinogenic quality, is illegal in the United States. It is a Schedule I substance under the Controlled Substances Act and carries the same legal penalties as heroin. But even more to the point, the studies you are reading about are complex and multilayered. They use specialized drugs in standardized doses. Participants take them under rigorously monitored conditions. Results are evaluated every step of the way.

Experimenting on yourself with unverified drugs in uncontrolled doses can be dangerous and lead to unforeseen consequences. Side by side with the research suggesting the beneficial applications of psilocybin mushrooms, recreational users are self-reporting significant challenges as well.

In an online survey completed last year, researchers at Johns Hopkins asked 1,993 individuals about their experiences with psilocybin mushrooms. Close to 40 percent said it was the most challenging experience of their lives. Eleven percent of respondents said they put themselves or someone else at risk while under the influence. Another 8 percent went on to seek treatment for psychological symptoms that didn't go away.

The researchers found that the difficulties users experienced were associated with taking too large a dose, and with being in an environment that felt unsafe. Both of these variables are hard to control in a real-world setting.

Treating depression -- and living with it -- is challenging. Finding the right combination of existing drugs to alleviate symptoms can take months of trial and error. In the interim, patients suffer. That's why the potential benefits of psilocybin mushrooms have fascinated researchers for some time.

In the 1950s and '60s, researchers in Europe began to explore the use of psychoactive drugs in mental health therapy. Their promising results encouraged similar research in the U.S. Between 2004 and 2008, scientists at UCLA did groundbreaking research into the effects of psilocybin on cancer patients who were gravely ill. The results showed that it significantly relieved their extreme anxiety.

In another study last year, researchers at Johns Hopkins administered psilocybin to cancer patients who were gravely ill. The sessions took place in pretty and comfortable settings, with two monitors present. Participants were encouraged to lie down, listen to music on headphones, and focus their attention inward on ideas, thoughts and emotions.

As with previous experiments, the outcomes were encouraging. Participants reported a substantial decrease in depression and anxiety, a result that endured for at least six months.

How psilocybin works, and why it is effective against depression, is not yet known. But with so much promise, the research continues.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: A new study said that prolonged antibiotic use is tied to colon polyps. But "prolonged" meant "two weeks or more." I had a couple of bacterial infections in a six-month timespan. How worried should I be?

Dear Reader: Antibiotics have undoubtedly revolutionized medicine, saving countless lives against multiple types of bacterial infections. However, with antibiotics readily available and a society that craves a quick fix, antibiotics have been overused. For example, they are often prescribed needlessly for upper respiratory symptoms that are not due to bacterial causes. Such overuse has led to the formation of antibiotic resistance; alterations of normal bacterial populations in the intestinal, oral and nasal cavities; and unnecessary side effects from the antibiotics themselves.

As for whether antibiotics can increase the risk of precancerous polyps in the colon, let's look at the evidence.

The study to which you're referring, published this year in the journal Gut, reviewed the antibiotic usage of 16,642 female nurses age 60 or older. In 2004, the women filled out a questionnaire reporting the amount of antibiotics they used between the ages of 20 and 39 and between the ages of 40 and 59. In 2008, the women filled out another questionnaire reporting their antibiotic usage between 2004 and 2008. All the women had at least one colonoscopy between 2004 and 2010.

Researchers found that women who took antibiotics between the ages of 20 and 39 had an increased risk of colon polyps compared to women who hadn't taken antibiotics. The increased risk was relatively small for women who had taken antibiotics for only one to 14 days within that 20-year period, but the risk increased significantly -- by about 1.4 times -- among women who took antibiotics for 14 days to two months. That heightened risk didn't increase further among women who took antibiotics for greater than two months.

For women who took antibiotics between ages 40 and 59, the rate of colon polyps increased more dramatically and was more dependent upon the length of antibiotic use. Those who took antibiotics for more than two months had a 1.69 times greater risk of developing colon polyps compared to women who hadn't taken antibiotics. Because colon polyps can eventually lead to colon cancer, the findings are worrisome.

Additionally worrisome are the findings of a 2008 Finnish study of people ages 30 to 79 assessing their antibiotic use from 1995 through 1997. The researchers found that people who had six or more prescriptions of antibiotics in that two-year timeframe had a 15 percent increased risk of colon cancer.

A possible theory about why antibiotics may lead to the formation of colon polyps, and later cancer, could be because they indiscriminately kill healthy gut bacteria. As this occurs, other, more unhealthy bacteria predominate in the colon, which can affect its immune response, leading to disruptions in its lining and the formation of polyps.

So, yes, there does appear to be some increased risk of colon polyps with antibiotic use. I wouldn't be overly concerned about two courses of antibiotics, though I would be concerned for a multitude of reasons about a repetitive use of antibiotics. Such use raises the need to look for new ways to prevent, and treat, infections.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I've always loved animals, and now I want to stop eating meat. But I'm 15 years old, and my parents think that's too young to make such a big decision. What can I tell them about being a vegetarian? I'm hoping I can persuade them.

Dear Reader: We think it's admirable that you want your lifestyle to reflect your beliefs. And we also understand how taking on a new diet might cause your parents to worry. As a teenager, you're in a period of growth spurts and hormonal shifts. Poor nutrition can affect your health, moods and learning ability. It may even play a role in susceptibility to disease in adulthood.

That said, the good news is that with proper planning, a vegetarian diet can be as nutritionally complete for people of all ages as one that includes meat. The vegetarian diet is often low in saturated fat and also high in dietary fiber. As a result, studies find that vegetarians often have a lower body mass index (BMI), lower blood pressure and more healthful cholesterol levels than people who eat meat. In addition, death from heart disease, stroke, Type 2 diabetes and certain cancers is lower among vegetarians than non-vegetarians.

You and your parents should start by deciding where on the meat-free scale of eating you wish to begin. Some vegetarians include milk and eggs in their diets. Vegans avoid all animal products, including honey and gelatin. And while it's not strictly vegetarian, some individuals skip red meat and poultry, but do eat fish and seafood.

When vegetarians decide to cut milk and eggs from their diets, alternative sources of protein, calcium and B12 become necessary. Protein can be found in soy products, beans, legumes and supplements. Small amounts of calcium are available in leafy greens and almonds. To get enough of the mineral, vegans often include calcium-fortified soymilk, juice and cereals, and calcium-set tofu in their diets.

Vitamin B12, found only in animal protein, is a vital nutrient. Your body needs it to make red blood cells, for proper neurological function, and to synthesize DNA. Vegetarians can get B12 in fortified products like cereals and soymilks, as well as in supplements.

Iron is a nutrient that vegetarians and meat eaters alike can fall short on. It helps your blood carry oxygen to muscles and organs, and is important for growth and normal cell function. Heme iron, which is most easily absorbed by the body, is found in lean meat and seafood. Nuts, beans, some leafy greens and fortified grain products are sources of non-heme iron, which the body doesn't use as efficiently. Vitamin and mineral supplements can help provide adequate iron, as well as other essential nutrients.

We've just hit the high points here. If and when your parents give you the OK to say goodbye to meat, we strongly recommend that you all become students of vegetarian nutrition. Your family doctor can help, and can also guide you to some excellent books and websites to help you plot your future journey.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)