Dear Doctor: I know that Adderall is prescribed to children with ADHD. But lately I've been reading stories about college kids who use Adderall to help them study. What is Adderall and who should take it?

Dear Reader: You've hit on a topic that's timely, complex and quite often controversial. When prescribed and used properly, Adderall can be beneficial. But as with any prescription drug, off-label use can create a host of problems.

Look at first-person accounts and you'll find numerous parents of children with ADHD -- that's attention deficit hyperactivity disorder -- who detail the ways that Adderall has helped their son or daughter. But it doesn't take much digging to find that abuse of the drug is a growing problem.

Let's start with the drug itself. Adderall is the brand name of a prescription drug composed of two stimulants -- amphetamine and dextroamphetamine. It has been approved by the Food and Drug Administration to treat children, adolescents and adults who have been diagnosed with ADHD, a condition marked by a cluster of disruptive behaviors. These may include agitation, lack of focus, disorganization, forgetfulness, fidgeting, excessive talking or frequent interrupting. Adderall is not approved for use by anyone younger than 6 years old.

As with all stimulants, Adderall increases the levels of dopamine in the brain. Dopamine is a chemical known as a neurotransmitter, which plays a role in learning ability, movement, attention, and in feelings of pleasure or even euphoria. Adderall helps people with ADHD feel calm and remain focused.

The problem is that Adderall abuse among young adults is rising. According to research conducted at Johns Hopkins University, the number of prescriptions for Adderall among young adults remains steady. However, levels of abuse, as well as visits to the emergency room due to adverse effects of that abuse, has spiked.

The newest research shows that misuse of Adderall is highest among young adults between the ages of 18 and 25. Although some may obtain their own prescriptions, most are either buying the medication illegally, or are getting it from family members or friends.

Between 2009 and 2011, the time period covered by the study, use of Adderall among young adults without a prescription rose by 67 percent. During that same time period, ER visits associated with non-prescription Adderall use rose by more than 150 percent.

The drug has a reputation as a study aid that increases concentration and sharpens focus. But non-prescription use of Adderall carries serious risks. Common side effects include stomach upset, increased heart rate, dizziness, dry mouth and mood swings. Adderall is a controlled substance, and possession without a prescription is a felony.

The bottom line is that non-prescription use of Adderall for any reason is both dangerous and illegal.

(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.)

Dear Doctor: I'm a 45-year-old man without any major medical problems. Is it worth it for me to get yearly physicals with my primary care doctor?

Dear Reader: That's a difficult question to answer. I have generally encouraged annual physical exams for most of my patients in their 40s and beyond. I schedule more time for this type of examination so that I can collect a history of a patient's lifestyle, conduct a review of their symptoms, and determine whether they have had the recommended colonoscopies, mammograms and vaccinations. With both the history and the physical examination, I learn aspects of the patient's health that were often not known to me prior.

From my subjective vantage point as a primary care doctor, I find value in these visits. But objectively, the benefit of physical exams is less clear.

Take a 1986 study comparing death rates of more than 5,000 men between the ages of 35 and 54 who'd had six health checkups to more than 5,000 men who'd had one checkup. Over a 16-year period, researchers found a decrease in death rates from colon cancer and hypertension among those men who had more checkups, but they found no decrease in death rates from other causes.

A 2007 article in the Annals of Internal Medicine reviewed 33 studies assessing the efficacy of health checkups. Researchers tried to determine if physicals caused benefit, caused harm, or had no impact on a patient's health. The largest benefit seen from physicals was through an increase in colon cancer screening. A more intermediate benefit was seen through the administration of Pap smears and cholesterol checks. The physicals also showed a benefit in decreasing worry among patients.

However, overall, the results showed no benefit seen in regard to death rates. The biggest problem with this assessment is that the different studies included so many variables, reaching conclusions proved difficult.

A 2012 British Medical Journal study analyzed a combination of 14 older studies assessing the benefits of health checkups. The study did not find any difference in death rates between those who had physicals and those who didn't. However, in one case, what the authors defined as the group receiving health checkups amounted to one physical over a 22-year period. In fact, participants in eight of the 14 studies evaluated had only one physical exam done for the time frame of their studies. The studies that showed more health checkups actually had better outcomes. The authors also tried to show if having physicals actually caused harm, but could not do so.

Obviously, the question needs to be studied further -- and electronic medical records give us the ability to do this. The critics of routine health checkups say they lead to unnecessary testing, possibly harmful tests and cost about $10 billion per year.

Yet I find that the most important aspect of the health checkup is the time to sit with patients -- to talk to them about their level of exercise, their diet, their drug habits and their level of sleep; to review whether they’re having shortness of breath, chest pains, or problems with urination or bowel movements -- and many times to learn about the stressors in their lives. This time is an important aspect to the doctor-patient relationship and is difficult to quantify.

So, if you are healthy, 45 years old and not on any medications, I would recommend that you get a health checkup every two years. But, of course, put your trust in your own primary care doctor's opinion regarding this matter.

(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.)

Dear Doctor: My daughter took her kids to the pediatrician the other day for their chickenpox vaccinations. Now, because I had chickenpox as a child, she's after me to get a shingles vaccine. What is shingles, and what's the connection to chickenpox?

Dear Reader: The same virus that causes chickenpox is responsible for shingles, a painful rash that can cause long-term problems. It's possible to get shingles at any age, but it's most common in adults 60 and older.

Here's what happens. Once the fever, rash and body aches of a bout of chickenpox have ended, the virus that caused the illness, called varicella-zoster, stays in the body. It lies dormant near bundles of nerve along the spine, known as the dorsal root ganglia. These are the nerves that pass sensory information -- a touch, a tickle, the pain of a bee sting -- from your skin to your brain.

Years after the initial infection, for reasons that still aren't entirely clear, the virus can become active again. As it begins to reproduce, the body reacts. Some people get flulike symptoms such as headache, sensitivity to light and a general feeling of illness. Others notice their skin is becoming tingly, itchy or painfully sensitive.

When the shingles rash appears, it's generally along only one side of the face or torso. It can look like a stripe, as it traces the path of the affected nerves. Tiny blisters form and re-form on the skin, and last for two to four weeks.

During this period the person with shingles is contagious. He or she can pass along a case of chickenpox -- but not shingles -- to anyone without immunity. The virus can be spread by direct contact with fluid from the rash. That's why anyone with shingles should steer clear of pregnant women, infants, unimmunized children and individuals with suppressed immune systems.

If shingles sounds like a difficult and unpleasant illness, you're right. During a case of shingles, even the touch of fabric on the affected skin can cause pain. The most common side effect is a condition known as postherpetic neuralgia, in which the severe pain of shingles persists for months or even years.

The good news (we imagine that you're ready for some about now) is that there is a shingles vaccine. It's made of live varicella-zoster virus that has been greatly weakened. It's enough to stimulate an immune response in your body, but not enough to cause problems in anyone with a healthy immune system.

We routinely recommend to our patients who are 60 or older, and whose immune systems are in good order, that they get a shingles vaccine. Protection lasts about five years. Some drugs, such as those for rheumatoid arthritis, as well as some cancer drugs, suppress the immune system. In these cases, the shingles vaccine should be avoided. There are other contraindications as well, so talk it over with your primary care physician to make sure a shingles vaccine is the right decision for you.

For those who do get the vaccine, it's important to note that it doesn't guarantee you will never get shingles. What it does is measurably lower your risk. And if you do still get shingles, the vaccine also reduces the likelihood of developing postherpetic neuralgia.

(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.)