I agree, TM can be extremelt beneficial. However there are a small number of people who are succeptible to depersoanlisation such as myself, and unfortunately for these individuals TM can act as a trigger for the condition. It will not trigger DP for most, but I am in the unfortunate minority. Also bear in mind that any exercise that encourages 'watching the active self' (As I understand it SES focuses on the 'two birds in a bush' section in book 10 of the Mundaka upanishad) is inherently dangerous because it involves a seperation of the mind, it is an exercise in depersonalisation. SES members will be familiar with the seperation of personal self from universal self (Something to do with param-atman and atman or Brahman I recall). There is a great deal of literature on the internet which deals with depersonalisation and hindu philosophy. I myself am not sure whether to focus on DP as a psychological condition or a philosophical standpoint, but for me DP is pretty damm far from enlightenment, it is feels more like an anxiety disorder; this is mainly due to the fact I had a panic reaction to the depersonalisation induced my meditating on the idea of a seperation between persoanl and absolute self. It is certainly an interesting idea for discussion though