What causes it, asked a reader last week? Readers had some interesting comments and observations to make, including one gentleman who has heard that the condition doesn't exist in Russia. Could it be because the old Soviet Union banned the use of amalgam fillings in 1960? This echoes the view of another reader who also believes the problem is linked to amalgam fillings, as he read a book by a sufferer whose condition cleared when he had his fillings removed and his body was detoxed. Could be down to a vitamin B deficiency, suggests another reader. Another suggests checking testosterone levels, whether the patient is male or female. The problem may be caused by levels that are too low.