Pubdate: Fri, 09 Jan 1998 Date: 09/01/1998 Source: Times, The (UK) Author: BARBARA BUTCHER Sir, The fact that GPs are prescribing Prozac for teenagers experiencing stress, anxiety and depression at exam time (report, August 21; feature, August 26) confirms the power of the pharmaceutical industry. Recent non-randomised clinical trials on the herb St John's wort indicate it to be as effective as Prozac, but with none of the side-effects. In addition, a recent paper published on the effect of psychological intervention on immunity during exam stress has shown that hypnotherapy prior to examinations increases both calmness and energy and improves mood. As there is no patent on hypnotherapy or St John's wort, it is not in the interests of those who command marketing budgets to publicise these facts. Yours sincerely BARBARA BUTCHER The Orchard Clinic 4 Orchard Lane, Amersham, Buckinghamshire HP6 5AB. August 27.