It must be emphasized that although the stability of perception with increasing sensory stimulation in HHPO patients is not significantly different than the stability of normal perceptions, these patients are manifesting extreme neurological reducing (F = 28.043, 1 and 8 df, p<.01). Indeed, t test analyses show significantly greater reducing at each of the three test-times (p values all <.01) between the HHPO and normal groups. Thus, it would appear that the substances associated with HHPO may not only reduce the augmenting - reducing range of the brain, but also depress cerebral activity to such a low level that the individual is now confronted with a dearth of sensory input. Petrie has suggested that extreme reducing may confront such individuals with a perceptual world that "... may become unbearable - not because of what it contains, but because of what it does not contain ... having to cope with a new problem - the problem of being confronted with nothingness" (1978, p. 66). This patient's extreme neurological reducing may not only produce a dearth of sensory stimulation, but may also adversely alter affective experiences and cognitive processes as well.

The HHPO patient may indeed be more severely ill than the HHPO-free individual, as Hoffer and Osmond (1963; Hoffer, 1966b) have suggested. They have reported that individuals with these endogenous substances required longer periods of treatment in hospital, had more re-admissions, and received more drastic treatment than patients without these chemicals. It may also be noted that when neurologically reducing schizophrenic patients were started on phenothiazine therapy, within one day there was a statistically significant increase in cerebral augmenting under conditions of relatively mild sensory stimulation (Kelm, 1985), not unlike the HHPO-free VFA in the present study.

As suggested earlier, most HOD test items deal with changing experiences, however, a number of statements also seek information about what appear to be relatively unchanging states. Examples of the latter may include: "Foods taste flat and lifeless" (item 49), "The world has become timeless for me" (127), "I feel as if I am dead" (131) and "I am not sure who I am" (145). In clinical diagnosis and in evaluating the results of treatment, it may be important to separate these two types of psychological experiences reflecting two very different neurological states. It may also be useful to analyze all of the 145 statements of the HOD in terms of these two states: 1) those that describe changing experiences and, 2) those that involve distortions, but are relatively unchanging.

Although the present study supports Hoffer's and Osmond's contention that HHPO patients have a more severe disease state than HHPO-free patients, it does not confirm their results that HHPO schizophrenic patients manifest greater perceptual instability than HHPO-free patients (Hoffer & Osmond, 1962; Hoffer, 1966b). Rather, it was HHPO-free schizophrenic patients who showed greater perceptual instability, as measured by the VFA.

Unfortunately, not all patients in the present study were given the HOD, but of those who did take the test (three HHPO and four HHPO-free patients), the direction of all but one of the scores shows that HHPO-free schizophrenic patients had higher HOD scores than those with HHPO. The median scores of the HHPO group were 42, 6, 4, 4, 1 and 7.2 compared with 78, 18, 4, 11, 5.5 and 11.1 in the HHPO-free group for TS, PerS, PS, DS, SF and RS, respectively. The mauvuria score (Hoffer & Osmond, 1961b, 1962) was 22 and 48 for HHPO and HHPO-free patients, respectively. The number of patients in these two groups was too small to do any very meaningful statistical analyses.