One study noted the many difficulties in evaluating LGATs, from proponents' explicit rejection of certain study models to difficulty in establishing a rigorous control group.  In some cases, organizations under study have partially funded research into themselves.Not all professional researchers view LGATs favorably. Researchers such as psychologist Philip Cushman, for example, found that the program he studied "consists of a pre-meditated attack on the self". A 1983 study on Lifespring found that "although participants often experience a heightened sense of well-being as a consequence of the training, the phenomenon is essentially pathological", meaning that, in the program studied, "the training systematically undermines ego functioning and promotes regression to the extent that reality testing is significantly impaired". Lieberman's 1987 study, funded partially by Lifespring, noted that 5 out of a sample of 289 participants experienced "stress reactions" including one "transitory psychotic episode". He commented: "Whether [these five] would have experienced such stress under other conditions cannot be answered. The clinical evidence, however, is that the reactions were directly attributable to the large group awareness training."