PSYCHOTIC killers, hyperactive children and bulimic teenagers may all behave the way they do because of a shared phenomenon: mineral deficiency, a US psychologist and mental health therapist says. The Hong Kong medical profession was yesterday urged by Dr Alexander Schauss to devote more resources to developing mandatory courses for medical students dealing with nutrition issues. This would shift the emphasis on prescribing drugs for behavioural disorders to finding natural cures. Research had shown a deficiency in certain minerals can have far-reaching consequences, he said. 'I think pharmaceutical companies have done a very good job of using the medical class as a training ground for doctors to use their products,' said Dr Schauss. 'There's lots of training in the use of drugs. In Hong Kong, it's not mandatory to study nutrition.' Dr Schauss is president and former executive director of Citizens for Health and founding honorary member of the British Society of Nutritional Medicine, and has also written several books. He is visiting Hong Kong and Guangzhou for a series of seminars on nutrition and behaviour. A deficiency in manganese has been linked to psychotic behaviour, Dr Schauss said, citing mass murderers Patrick Henry Sherrill and Charles Manson as examples. 'Studies at the University of California have shown elevated levels of manganese results in violence in humans. 'A UCLA study also found that if mothers breast-fed their infants, it would lower the level of manganese into the brain of the child. 'We may have made a mistake by not encouraging mothers to breast-feed their children. It may be one of the reasons why we are seeing more crime in the US - because so few children were breast-fed in the 50s and 60s,' he said. Eating disorders could be combated by addressing zinc levels, he said, citing research in the States. Dr So Kai-ming, vice-president of the Hong Kong Medical Association, said moves to make nutrition a compulsory study course would win support. 'At the moment it's part and parcel of the whole medicine course, there's not nutrition as a subject alone. 'It's all to do with a limitation of time. There's so much to learn in medicine. 'But nutrition is becoming more and more important these days, it certainly is a good suggestion to expand the subject,' he said.