A drug addiction is characterized by a compelling urge to use the drug for the prevention or relief of distressing mental and physical disturbances which occur when the necessary dose is delayed or omitted. A drug habit is also characterized by an urge to use the drug, but this is not compelling. The abstinence symptoms, which are expressions of nervous states, are not particularly distressing and do not occur as long as the person's attention is placed on other matters. ,
Drug tolerance in the narrower sense used here means that larger doses than those originally used are required to bring about the effects desired by the subject. In the case of morphine, tolerance develops because of addiction, but in other instances tolerance may be present without addiction and addiction without tolerance. When both are present the matter takes on greater importance because of the extremes to which the addict goes to obtain the drug constantly and in increasing quantities.
As our group of subjects included 48 users of marihuana, opportunity was afforded for some conclusions concerning marihuana addiction and tolerance. Practically all of our group of users stated that they could and often did voluntarily stop the smoking for a time without any undue disturbance from the deprivation. In the sociologic study reported by Dr. Schoenfeld it was found that smokers had no compelling urge for marihuana. If "reefers" were not readily available there was no special effort made to obtain them from known sources of supply. Dr. Walter Bromberg, Psychiatrist-in-Charge, Psychiatric Clinic, Court of General Sessions in New York, states: "The fact that offenders brought up on marihuana charges do not request medical treatment on their incarceration (with its cessation of drug supply) argues for the absence of withdrawal symptoms." From interviews with several hundred marihuana users he concludes that true addiction was absent.
The evidence submitted here warrants the conclusion that as far as New York City is concerned true addiction to marihuana does not occur.
The evidence concerning acquired tolerance is less clear-cut. Tolerance develops during the periods when the drug is being taken and accounts for the necessity of increasing the dosage to bring about the desired effects. How long the tolerance persists after the drug administration is stopped has not been definitely established in any instance.
The statements of marihuana usage and time since stoppage given by eight of our subjects are summarized in Table 26.
On one or more of the numerous occasions on which marihuana was administered each of these subjects received what was considered a minimal effective dose. One (J.B.) was given 1 cc., another (A.B.) 3 cc., the others 2 cc. In all instances the customary physical effects, conjunctival injection, dilated and sluggishly reacting pupils, tremors and ataxia, were observed. With these doses the subjects also experienced the sensation described as "high." The only conclusion warranted here is that if acquired tolerance does occur it persists for a limited period only.
Further evidence, though indirect, was brought out by Dr. Shoenfeld's investigation and by personal interviews with our 48 users. There is agreement in the statements that among users the smoking of one or two cigarettes is sufficient to bring on the effect known as "high." When this state is reached the user will not continue smoking for fear of becoming "too high." When the desired effects have passed off and the smoker has "come down," smoking one cigarette brings the "high" effect on again. This could not be the case had a steadily increasing tolerance developed.
The evidence available then—the absence of any compelling urge to use the drug, the absence of any distressing abstinence symptoms, the statements that no increase in dosage is required to repeat the desired effect in users—justifies the conclusion that neither true addiction nor tolerance is found in marihuana users. The continuation and the frequency of usage of marihuana, as in the case of many other habit-forming substances, depend on the easily controlled desires for its pleasurable effects.
1 Bromberg, W. "Marihuana: a psychiatric study." 1.A.M.A. 113:4, 1939.