My teenage children are due to return to school soon after two months of staying up late and having irregular sleeping hours. Every year it gets worse - they can't get up in time for school when the vacation is over. Do you have any advice for bringing them back to reality? F.G., Tel Aviv Dr. Grace Pien, a sleep medicine expert at the University of Pennsylvania, says: Delayed sleep phase syndrome (DSPS) - when your body's circadian rhythm makes you want to go to bed much later than what's considered a normal bedtime - is quite common in adolescents and young adults, especially after the summer vacation from school and college. About seven percent of teenagers suffer from DSPS. There is no known cure, but there are treatments to manage this chronic sleep disorder. When patients come in, they think they're suffering from insomnia, saying they go to bed around 11 p.m. but have trouble falling asleep until hours later. When I dig deeper into it, they tell me that on the nights they stay up late, they have no difficulty falling asleep and once they do go to sleep, they stay asleep until late morning or early afternoon. These so-called "night owls" have difficulty making it to morning appointments or school. They have normal sleep cycles, but they just can't fall asleep until very late. Part of it is "how you're wired" and part of it is attributed to late-night social behaviors. DSPS is treatable. For most people, once an external schedule is imposed upon them for work or school where they have to get up early, they are able to adjust their sleep habits, go to bed earlier and meet their obligations. But for others, there is a real difficulty in adjusting to an earlier sleep schedule, and they should see a sleep physician for behavior modification or bright light treatment. Have your teens stick closely to a strict sleep-and-wake schedule so they don't go to sleep too late. Align that schedule with where you want it to be (for example - to bed at 10 p.m. and up by 7 a.m.). Keep them to the schedule, as sneaking in just one or two late nights can make the body's circadian rhythm slide right back into the old delayed schedule. The US National Sleep Foundation recommends these basic daily sleep requirements: Preschoolers need 11 to 13 hours; elementary school pupils 10 to 12, pre-teens: nine to 11 and teens eight to nine. I am a 42-year-old man who generally enjoys good health. For the last few months, I have been suffering from an odd sensation - a burning feeling in my mouth and on my lips and gums. I asked my dentist about it, but he didn't see anything in my mouth or have any advice except to gargle with mouthwash, which didn't help. What could this condition be and how can it be treated? M.S., Beersheba Judy Siegel-Itzkovich answers: A recent issue of the Mayo Clinic Health Letter describes your condition, which is called burning mouth syndrome. It notes that the condition can be a complex and frustrating condition to diagnose and treat, but adds that with persistence and help from your doctor, symptoms usually can be improved. Burning mouth syndrome can affect the tongue, lips, gums, palate or throat. Some people experience tingling, numbness, a sore mouth or a metallic, bitter taste. It can last a few weeks or drag on for years. Despite the symptoms, there are no abnormalities in the mouth, and it's not contagious or infectious. It can affect anyone, but is more common in people older than 60. It's unusual for burning mouth syndrome to be attributed to just one cause; typically, many factors play a role. It may be linked to several medical conditions including hormonal imbalances, gastric reflux, Sjogren's syndrome, underactive thyroid, oral yeast infection and dry mouth. Other possible contributors include medications, vitamin or mineral deficiencies, allergies to foods or food additives, oral irritation or psychological factors such as stress, depression or anxiety. Your doctor may ask you to change medications if they dry out the mouth. Humidifying your home, drinking more water and using saliva-stimulating medication might help. You may be tested and then treated for an underactive thyroid. Nutrient deficiencies can be addressed with supplements. Allergy triggers can be determined and avoided. If symptoms persist, psychiatric therapy or cognitive and behavioral therapy may be helpful. Some drugs used to treat psychiatric conditions also work well in managing pain, including certain antidepressants and anticonvulsants. Rx For Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx For Readers, the Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or e-mail it to email@example.com, giving your initials, age and residence.