They differ in the process used, in brainwave patterns and in results
Mindfulness is described as a state in which one is highly aware and focused on the reality of the present moment. Mindfulness meditation teaches people to be aware of thoughts and perceptions without judging or holding on to them. It aims to teach people to approach stressful situations ‘mindfully’, so that they are better able to deal with them.
Transcendental Meditation does not involve monitoring one’s thoughts or breath, nor is it concentration, contemplation or ‘controlled focus’ (category 1 above). In Transcendental Meditation, one systematically goes beyond mental activity—transcending thoughts, perceptions and sensations—to experience finer states of thought or earlier stages of the thinking process, until one arrives at the source of the thinking process, a state of inner silence. By directly contacting this inner, transcendental source, mind and body are refreshed, stresses get dissolved and mental potential is enlivened, accelerating personal growth.
The main point here is that Mindfulness works on the level of changing attitude, whereas Transcendental Meditation works on the level of producing a physiological state in which the body heals itself, with consequent benefits for mental abilities, emotions and behaviour.
The laudable aims of Mindfulness—increased awareness, improved focus, a healthier recovery from stress and more harmonious behaviour— all result spontaneously as a by-product of TM practice, and increase naturally without the person having to strive consciously to achieve such qualities by practicing mindfulness techniques.
Different Meditation techniques produce different Results and Benefits
Mindfulness: There is by now quite a lot of research on Mindfulness, but most of the areas studied involve psychological variables rather than physical function. They show that it does help reduce anxiety and to improve attitude towards medical conditions. Pain has been studied a lot: there is little evidence that Mindfulness changes physical function but it does improve coping with pain.
There is no evidence that Mindfulness changes physical function in cardiovascular disease, an area where TM research is particularly strong.
A common criticism in the literature of much of the research on Mindfulness is that it does not control for placebo effects. Participants receive a lot of attention, social support, and expectation of benefits from the program; and most of the studies are short-term psychological changes from before to after the 8 week course.
In contrast to TM research, there are only a small number of ‘controlled’ studies on Mindfulness, i.e. studies that involve a ‘control group’ — a group of people who do not practice the meditation and whose results are compared with the meditator results.