Here are some signs your baby may be ready for solid food, courtesy of the U.S. National Library of Medicine:

• She is now double her birth weight.
• She can support her own head and neck well.
• With some help, she is beginning to sit up.
• Expressing that she is full by closing her mouth or turning her head away from the food.
• Expressing an interest in solid foods that other people are eating.

MONDAY, May 12 (HealthDay News) -- An estimated 750,000 American teens and young adults are problem gamblers according to researchers at the University at Buffalo's Research Institute on Addictions.

Problem gambling is defined as gambling associated with three or more negative consequences, such as gambling more than you intended or stealing money to gamble.

The national telephone survey of almost 2,300 respondents, ages 14 to 21, found that 2.1 percent were problem gamblers, which works out to a nationwide total of about 750,000 young problem gamblers, the researchers said.

They also found that 11 percent of respondents gambled twice a week or more -- considered frequent gambling -- and that 68 percent of respondents said they'd gambled at least once in the past year.

The findings of the survey, conducted from August 2005 through January 2007, are available online and were expected to be published in the June 2008 issue of the Journal of Gambling Studies.

"In a society where young people are increasingly exposed to gambling influences, there is cause for concern," principal investigator John W. Welte said in a prepared statement.

"As might be expected, all statistically significant results showed that greater gambling involvement is associated with aging into an adult status. In fact, gambling may be associated with the transition into adulthood," said Welte, a senior research scientist at the Research Institute on Addictions.

The study found that gambling increased with major life changes such as getting a job, leaving school, living independently from parents, and marriage. Young people who worked full-time were more likely to gamble, those who weren't in school were more likely to gamble frequently (twice a week or more), and those who lived independently were more likely to gamble and to be problem gamblers.

"As far as gender, it seems likely that females' gambling involvement tends to emerge in adulthood, while male involvement can be high in adolescence. We found identical problem gambling rates for adult males and young males (4 percent). We found adult females' gambling rates were much higher (3 percent) than that of young females (less than one-tenth of a percent). In other words, problem gambling is almost non-existent among female adolescents and young adults," Welte said.

Among the other findings:

• Black youth were less likely to have gambled than white youth. But if black youth gambled, they were more likely to be frequent gamblers -- 30 percent vs. 12 percent.
• Asians had the lowest gambling involvement.
• Native Americans were more likely than whites to be frequent gamblers (28 percent vs. 9 percent) and were more likely to score higher on measures of problem gambling. This may be a reflection of the rapid spread of legal gambling on Native American reservations.
• In general, young people with low socioeconomic status were less likely to gamble. However, if they did gamble, they were more likely to be problem gamblers.
• Young people in the highest socioeconomic groups had the lowest gambling involvement, the survey found.

More information

The American Academy of Family Physicians has more about problem gambling.

MONDAY, May 12 (HealthDay News) -- Only about 5 percent of people with multiple sclerosis are diagnosed when they're children, but like adults with MS, the disease can affect cognitive function, causing memory and attention problems, and possibly low IQ scores.

And, the younger a child is at the time of diagnosis, the more likely he or she is to have a low IQ, according to new research published in the May 13 issue of the journal Neurology.

"In childhood cases, the impact of the disease on cognitive functioning may be more dramatic than that observed in adults," said study author Dr. Maria Pia Amato, an associate professor of neurology at the University of Florence, in Italy.

Multiple sclerosis is a disease of the central nervous system. The disease leads to the destruction of myelin -- a protective coating found on nerve cells. Without their myelin coating, the nerve cells can't efficiently send signals between the brain and other parts of the body. Within the brain, this can slow or stop nerve impulses, according to Nicholas LaRocca, vice president of health care delivery and policy research at the National Multiple Sclerosis Society (NMSS). Additionally, he said, MS can cause a gap in nerve fibers, and, in some cases, can actually cause brain tissue to shrink.

"The overall organization of the brain is being impaired," he said.

LaRocca's colleague, Rosalind Kalb, vice president of the professional resource center at NMSS, said most people describe the effects of the disorder as feeling as if their brain "has slowed way down."

"What that means for a child in a school situation is that if the incoming information is coming in faster than that person can process it, they won't remember it later, because they didn't get to process it effectively to begin with. So, they don't learn what they need to learn," said Kalb, who along with LaRocca wrote the book, Multiple Sclerosis: Understanding the Cognitive Challenge.

An estimated 250,000 to 350,000 Americans are believed to have multiple sclerosis, according to the U.S. National Institute of Neurological Disorders and Stroke. The course of the disease is highly unpredictable, with some people experiencing only mild symptoms, while others are disabled by it. Many people also have periods of remission, when they have no symptoms.

And, that same variability holds true for cognitive symptoms. "These kids aren't developmentally disabled. Some will experience problems, and some won't. They have to learn to use their strengths to compensate for the pockets of problems that can affect their learning," Kalb said.

Amato's study included 63 children with MS and 57 healthy "controls." They ranged in age from 8 to nearly 18, with an average age of 15. Each child completed numerous tests to assess different areas of cognitive function.

Thirty-one percent of the children with MS were deemed to have a cognitive impairment, which meant they failed at least three of the tests.

"Five patients (8 percent) exhibited a particularly low IQ, less than 70, and we found that a lower IQ was significantly associated with a younger age at onset. Only one case had an MS onset after 13 years of age, whereas in the remaining four children, MS started before 13 years of age," Amato said.

Additionally, she said, "MS negatively affected school and everyday activities in 56 percent of the subjects."

LaRocca said the findings are similar to what has been seen in adults, and what this study really does is "call attention to the fact that these youngsters need special attention and support. You'll find some functions affected, some severely, some mildly and some not at all, and you'll find certain strengths you can work with." For example, "if verbal memory is affected, but visual memory isn't, use more visual cues in teaching," he advised.

Amato added: "In general, treatment and support may help the [child] and the family to cope with psychosocial difficulties. Moreover, it is possible that brain plasticity, as well as reparative and compensatory abilities, may be more efficient in this age range. Therefore, early treatment strategies, both rehabilitative and pharmacological, may lead to a better outcome."

The study was funded, in part, by a grant from drug maker Biogen-Dompe, which produces medications for MS.

More information

To learn more about multiple sclerosis, visit the National Multiple Sclerosis Society.

The U.S. National Library of Medicine offers these suggestions when talking to children about death:

• Keep your explanation honest, simple, and on a level that's appropriate for the child's age.
• Understand that death can cause fears and confusion in many children.
• Talk about it as openly as possible when they ask questions or if a situation occurs that requires you to discuss it.
• Talk about your feelings -- fear, sadness, anger and anything else you feel. Show your child that the emotions they have are normal.
• Help children understand that they had nothing to do with the death. The person did not die because of something the children did, and they could not have prevented it from happening.

In research with mice, they found this class of drugs also suppresses the adaptive rewiring of the brain necessary for neural development in young animals. The findings are in the May 8 issue of Neuron.

One such drug is rimonabant (Acomplia), which was developed by Sanofi-Aventis and is awaiting approval by the U.S. Food and Drug Administration. Other pharmaceutical companies are developing similar drugs.

In this study, researchers concluded that a cannabinoid receptor-blocking drug called AM 251 affected experience-dependent cortical plasticity in the brains of juvenile mice. This plasticity is the experience-prompted adaptive rewiring of the brain that plays an critical role in the neural development of young animals.

"Our finding of a profound disruption of cortical plasticity in juvenile mice treated with AM 251 suggests caution is advised in the use of such compounds in children," wrote Mark F. Bear and his colleagues, of the Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, in Cambridge, Mass.

More information

The Nemours Foundation has more about childhood obesity.