One in five Chinese mentally ill Almost one in five mainlanders may be suffering some form of mental disorder, with most receiving no treatment, say World Health Organisation researchers, based on a study of almost 80,000 people in four provinces (rural and coastal) from 2001 to 2005. This new figure of 17.5 per cent of the population is much higher than earlier estimates, which range from 1.1 to 9.1 per cent. The most common problems are mood, anxiety and substance-abuse disorders, Reuters reports. Of those with a diagnosable mental illness, 24 per cent were moderately or severely disabled as a result, yet only 8 per cent had sought professional help. Mental illness figures under-reported Meanwhile, mental-health experts in India warn of under-reporting and a lack of resources, due largely to the stigma associated with such disorders. Nimesh Desai, head of psychiatry at New Delhi's Institute of Human Behaviour and Allied Sciences, estimates there are fewer than 4,000 psychiatrists and even fewer general mental-health professionals, which 'meets about 5 per cent to 7 per cent of the projected need'. Experts estimate that up to 20 million Indians suffer mental disorders - almost 19 per cent of the population, AFP reports. Link between cancer, evolution found Higher rates of cancer may be one of the costs of human evolution, say US researchers, based on their studies showing that the genes of chimpanzees are much better at apoptosis, or programmed cell death, which is one of the key ways the body kills off cancer cells. Team leader John McDonald, of the Georgia Institute of Technology, says the difference 'may have evolved as a way to increase brain size and associated cognitive ability [at the cost of] an increased propensity for cancer'. Previous studies have shown that chimps have lower rates of cancer than humans, healthday.com reports. Rear-facing car seats recommended Parents should keep children in rear-facing car seats 'for as long as possible' and at least to the age of four because they fare much better in accidents that way, say British researchers. The conclusion by the Royal Surrey County Hospital team is based on a review of European and US studies. Unlike forward-facing seats, those that face backwards keep the head, neck and spine aligned so any impact is better distributed, AFP reports. Lack of naps causes hyperactivity Children between the ages of four and five who no longer take daytime naps exhibit more symptoms of hyperactivity, anxiety and depression even if they get the same amount of sleep over 24 hours as those who nap, say US researchers, based on a small pilot study. The Pennsylvania State University team concedes that children who are prone to hyperactivity may be less likely to nap in the first place, Reuters reports. 'But it's possible napping is important for optimal daytime functioning at this period of development,' it says. Yoga helps those with asthma Yoga appears to ease the symptoms and improve the quality of life of people with asthma, even enabling them to cut back on medication, say US researchers, based on a small study in which patients practised three times a week for 10 weeks. The New York University team used hatha yoga, which focuses on deep breathing. Patients improved by 43 per cent on average in terms of frequency and severity of symptoms, activities associated with breathlessness and social and psychological functioning, reports healthday.com. 'There's not much of a downside to yoga,' the researchers say.