This chapter describes a study done at Stanford Research Institute (SRI) to determine what, if any, are the negative effects of transcendental meditation (TM). It summarizes an experiment conducted at SRI to determine whether people who adopted the practice of TM were a self-selected population or whether a relatively disinterested random sample of volunteers could realize the benefits claimed to accrue to practitioners. The TM group received the standard training at a local chapter of the Students International Meditation Society (SIMS), the parent organization of TM. The problems the TM subjects experienced were interpreted by the SIMS organization as being caused by "unstressing"—a phenomenon claimed to be a natural consequence of the initial stages of TM. More of the naive meditators who had decided to become teachers of TM reported becoming depressed, frustrated, impulsive, and/or as experiencing greater physical and mental tension and suspiciousness since starting TM than did the naive meditators in the SIMS random sample.