Interesting article in the latest edition of Golf Monthly on this subject. It seems that a significant percentage of golfers do suffer to some extent from the yips and there are two types, the acceleration yips and the rotational yips. Think I suffered from both! It is not normally a psychological condition. Previous advice has generally been to find another way of putting, such as using broomhandle or belly putters, or a different grip such as left hand below right or the claw grip, but the first two are being outlawed in the next version of the rules. However, the article claims that the yips can be cured by minor changes in technique. I will give this a try and report back. 