Book: Getting Rid of Ritalin  by Robert W. Hill and Eduardo Castro Price: $ 19.95     Four million children take Ritalin to control their attention deficit disorder (ADD), or hyperactivity. While Ritalin is reducing ADD symptoms in some cases, it is not always effective, often has undesirable side effects and does nothing to treat the underlying cause of ADD.     Psychiatrist Eduardo Castro and psychologist Robert Hill say it's time to replace Ritalin with neurofeedback—an innovative, scientifically proven form of brainwave biofeedback that teaches patients how to control their own brain. The authors have used this modality to successfully treat hundreds of children and adults with ADD and found it effective for 75-80% of clients.     The authors say that slow brain wave activity is at the core of ADD, which is marked by poor, disordered regulation of the brain's arousal state. Unlike Ritalin, which only works as long as you take it, neurofeedback teaches the brain how to increase and maintain its speed permanently. Here's what Drs. Castro and Hill say about neurofeedback:     "Neurofeedback is the logical replacement for Ritalin because it works better, is safer, and addresses the core problem rather than treating a symptom. Neurofeedback is a sophisticated form of biofeedback that has been demonstrated to be highly effective in treating dozens of physical and psychological disorders.     "This is, at last, a quick, noninvasive, cost-effective treatment for attention deficit disorder and its cluster of companion disorders. Neurofeedback is a natural, self-regulating approach that helps restore the brain's ability to function in the manner in which it was designed to function. Once brain wave patterns begin to normalize, all the symptoms in the cluster of problems begin to improve. Neurofeedback is perhaps the biggest breakthrough in noninvasive medicine in the last 50 years."     Drs. Castro and Hill draw on dozens of actual case histories of children and adults whose ADD is a condition of the past. And they explain the role of good nutrition and health practices, the need to eliminate toxic substances from the lifestyle, the health effects of too much television, and the need for sensitive parenting. To aid parents in locating a neurofeedback provider, they include a list of practitioners around the country.