Rare cases of full-blown acute psychotic episodes precipitated by marihuana use are reported in individuals with histories of mental disorder, with marginal psychological adjustments or with poorly developed personality structures and ego defenses (Talbott, 1968; Heiman, 1968; Kaplan, 1971; Pernot, 1969; Keeler, 1968; Defer and Diehl, 1968; Wurniser et al., 1969; Allentuck and Bowman, 1942; Bromberg, 1939; Bromberg, 1934; Curtis and Wolfe, 1939; Hughes et al., 1970; Isbell et al., 1967; Keup , 1970; Keeler, 1967; Talbott and Teague, 1969 Mayor's Committee, 1944).

Marihuana intoxication may hinder the ability of these, individuals to maintain structural defenses to existing stresses, or, alternatively produce a keener awareness of personality problems or existing stresses (Smith, 1968). Psychotherapy and antipsychotic medications are useful in controlling and preventing this reaction (Weil, 1970).

Exceptionally rare reports from North America of nonspecific toxic psychosis or actite brain syndrome have occurred after extremely high drug dose consumption, although such reports are, more common in the eastern countries. These conditions are self-limited and clear spontaneously as the drug effect abates (Weil et al., 1968; Bartolucei et al. 1969 Ames, 1958; Isbell et al., 1967; Mayor's Committee, 1944; Williams et al., 1946).

Finally, marihuana intoxication may trigger delayed anxiety reactions or psychotic episodes in a small percentage of persons who have prior experience with hallucinogenic drugs (Ungerleider et al., 1968; Ungerleider, 1969; Weil et al., 1968; Favazza and Domino, 1969).

In summary, the acute psychomotor-cognitive effects of marihuana intoxication are, interesting academically to gain understanding of normal and abnormal mental function. Also, for practically determining the danger-risk factor for the individual including determination of his functional level personally, vocationally and socially in this society. The effect on personal-social-vocational function is highly individualized and difficult to predict at present.

Although reports of anxiety attacks and psychotic episodes are more frequent as marihuana use spreads, they are still exceedingly rare and their incidence appears to be decreasing as use becomes more acceptable to more diverse populations. For example, during the nine-year period of 1961 to 1969, out of 701,057 admissions to Los Angeles County Hospital, located in a, city with very high marihuana use, only three patients required hospitalization for psychic sequelae of marihuana smoking (Lundberg, et al., 1971).

In contrast, many cases are being seen in Vietnam soldiers where a extremely potent material is available and daily stresses are high, but, these probably represent only a small fraction of marihuana, users (Talbott and Teague, 1969; Talbott, 1968; Heiman, 1968).

During the, academic year 1968 and 1969, eight students were seen in the mental hygiene division of a private Eastern University student population (8,500) with acute anxiety reactions (Bialos, 1970). The frequency of marihuana-associated acute adverse, anxiety reactions requiring attention at Boston University Student Health Service (student population 20,000) is between five and seven yearly (Pillard, 1970).

In a recent survey of newly admitted patients to a large mental hospital, marihuana was the direct cause of the hospitalization in only 0.9 per thousand admissions (Keup, 1970).