Over the years, numerous studies have relied on offender populations and zero-order statistical correlations to "demonstrate" a cause-effect relationship between marihuana and crime. This method of " proof by enumeration" has become probably the most common approach to "demonstrating" the purported causal relationship.

As Goode (1970) has noted, however:

Not even marihuana's staunchest supporter would argue that a crime has never been committed by a user while high. Yet, incredible as it seems, the burden of many proofs of marihuana's criminal effects has been precisely the simple fact that it is possible to locate crimes committed in conjunction with smoking marihuana. "Proof" by enumeration is no proof at all. By examining an enumeration of crimes which were committed under the influence of marihuana (even were this definitely known), it is impossible to determine the " cause" of the event taking place, in this ease the crime-or, indeed, that marihuana has anything whatsoever to do with its commission (pp. 215-216).

Even if these studies are taken at face value, their findings do not generally support the thesis of a positive and significant statistical association. In most instances, marihuana has not been found to predispose one to commit crime or to serve as an initiator of criminal careers; nor does the use of the drug appear to alter the progression to other non-drug offenses among those without prior criminal records or histories of psychological maladjustment. Predictably, however

the data do indicate a greater rate, of progression among marihuana-using offenders (both those arrested specifically for their marihuana offenses and those charged with non-drug crimes) than that which might be expected from similar, non-using offenders or from the general population.

Because these studies do provide at least interesting insights into the possible nature and direction of a relationship between marihuana and crime or, conversely, a non-existent relationship, several of these studies are summarized below.

Bromberg, 1939. Between 1932 and 1937, Bromberg and his team of researchers reviewed all cases eventuating in conviction by New York's Courts of General and Special Sessions; conducted interviews with about 17,000 drug and non-drug-using offenders; and analyzed the statistics from both courts. The report of this work, published in 1939, yielded the following information.

Among the 16,854 offenders convicted of felonies in the court of General Sessions, 67 (.005%) were identified as marihuana users. Of these 67, 46 (697c) had been convicted on charges of possession with intent to sell; 16 (24%) were charged with burglary, robbery and grand larceny; two persons were charged with assault and one each was charged with petty larceny, forgery and murder.

The researcher points out that in only nine cases did the, offenders' criminal records commence with a drug charge, "indicating that there was not in those cases a close relationship between drugs and the beginning of a career in crime" (p. 10).

In a 25% random sample of offenders convicted in the Court of Special Sessions (misdemeanors), 135 or 9% were charged with possession of marihuana. Of these 135, 93 or 69% had no previous record, 8 had been charged previously with drug violations only, 5 had mixed drug and non-drug charges and 29 (21%) had only non-drug arrests. In summary, the researcher stated that:

As measured by the succession of arrests and convictions in the Court of General Sessions (felonies) . . . ,

it can be said that drugs generally do not initiate criminal careers. Similarly, in the Court of Special Sessions (misdemeanors), only 8% of the offenders had previous charges of using drugs and 3.7% had previous charges of drugs and other petty crimes. In the vast majority of cases . . . then, the earlier use of marihuana apparently did not predispose to crime, even that of using other drugs. . . . The expectancy of major crimes following the use of cannabis in New York County is small, according to these experiences (p. 10).

Bromberg and Rodgers, 1946. A study of 8,280 naval and marine prisoners at the U.S. Naval Prison in Portsmouth, New Hampshire (1946) revealed that 40 or .0048% of the offenders were marihuana users. The offenses they committed while in the service were: AWOL or AOL (32, or 80%), assault or striking an officer (3), theft (3), and narcotics violations (2). Their previous civilian offenses included three each of assault, theft and traffic violations and one each of gambling and narcotics violations, drunkenness, draft dodging, and violation of the Mann Act. Twenty-eight or 70% of the marihuana users had no previous civilian criminal records (p. 825).

The preponderance of psychiatric disorders in the user group over the non-users (40 randomly selected non-using naval prisoners) led the researchers to conclude that "marihuana usage is but an aspect of some type of mental disorder or personality abnormality" (p. 826), a conclusion also reached by Charen. and Perchan 1946), Ausubel (1958), Andrade (1964), Lambo (1965), Bloomquist (1968), Simmons (1969) and Grinspoon (1971).

Gardikas, 1950. The researcher reviewed the criminal records of "379 individuals either sentenced or arrested flagrante delicto for using hashish publically" between 1919 and 1950. More than half (55%) of these individuals were already known to law enforcement authorities prior to their use of hashish and an additional 14% had no subsequent difficulties with the law except for hashish and vagrancy offenses. The researcher notes, however, that the remaining 117 offenders (31% of the original sample) went on to become " confirmed criminals after their first hashish arrest."

Dividing this last subgroup of 117 into three approximately equal parts, Gardikas. then described the subsequent criminality of each group. The first group was given 332 more sentences following their first sentence for using hashish; 142 (43%) were additional hashish offenses, a similar number were for violent crimes or crimes involving weapons, 18 were for "insults" and two were for "high treason."

In a critique of the Gardikas study, Kaplan were accumulated; mostly for hashish offenses (42%) and thefts (20%). Although there were a small number of violent crimes subsequently committed by this group of offenders, most sentences subsequent to their initial hashish sentence were for such relatively minor offenses as illegal gambling, living on immoral earnings, "false statements of identity," and "fishing with dynamite,."

The, third group discussed by Gardikas, comprised of those "who after having, made use of hashish became criminals," accumulated 332 additional sentences. Hashish offenses were again responsible for 30% of these offenses and most of the rest were for theft. Gardikas notes with respect to this group that although not all of these individuals were criminal before they used hashish, their use of hashish "turned [them] into habitual hashish smokers and habitual criminals with a, strong propensity leading toward crime of dishonesty and particularly theft and f rand. At least one-half of them surely and undoubtedly are even to be characterized as dangerous idle, vagrants" (p. 203).

In a critique of the Gardikas study, Kaplan (1971) has stated that:

The basic problem underlying Gardikas' paper is his conclusion that hashish use caused his subsample of 117 arrests to become criminals. This assumes, first. that they had not engaged in crime before beginning to use hashish and, second, that it was the hashish use and not something else that turned -them toward crime. Neither of these assumptions is justified by the data. . . . As for the first assumption . . . all we know is that they had not been arrested or convicted for other crimes first. . . . The second assumption . . . is also impossible to justify. Even if the members of the subsample had not previously been criminals, it may very well be difficult to distinguish the criminogenic effects of hashish from those of conviction and sentence to Greek jails.

Even aside from any criminogenic effect of the Greek penal system, the figures may indicate only that once somebody has been arrested for hashish-and probably served a term in jail as well-lie is more likely to be picked up by the police when further crimes are committed. Finally, the years from 1919 through 1950 . . . were a period of enormous social dislocation [in Greece] . . . . It is obviously an almost impossible task to sort out how much of the subsequent criminality in the subsample was due to hashish use and how much to the social chaos that prevailed in Greece (pp. 103-104).

Andrade, 1964. The researcher retrospectively reviewed the examinations of 120 patients sentenced between 1951 and 1960 by a Brazilian Court to Heitor Carrilho insane asylum. Sentencing in all cases was based on the allegation that cannabis was directly responsible for their crimes. The researcher concluded that:

In the 120 patients examined, we did; not find any criminogenic action that could be attributed to cannabis; ... In the majority of cases examined (83), we found patients with psychotic disturbances. . . . In the cases in which we did not find mental disturbances, a total of 37, the crime attributed to them was that of carrying or selling marihuana.... In the study of the dynamics of the crimes of all the others, we saw that there was a link between the crime and the illness, independent of the use of cannabis (Tinklenberg, 1971: 12).

Lambo, 1965. The researcher compiled lists of crimes occurring over a, two year period in three West African nations and recorded the number of offenders perpetrating these crimes. He found that approximately one-fourth of the offenders had previous convictions. Forty-seven percent of the 863 offenders convicted for false pretenses, 61% of the 2,880 convicted burglars and 54% of those convicted on charges of "culpable driving" were said to have histories of cannabis use. Many of these users, however, were also shown to have long histories of psychological maladjustment (p. 10). The researcher suggests that "the use of cannabis enhances suggestibility in certain individuals, and this may be a factor in the commission of crime, by these chronic abusers" (p. 11).