In evaluating the histories and treatment needs of drug abusers, a precise method for quantifying degree of drug involvement would be advantageous. This method should utilize information which is reliable and readily available, and each item of information should contribute to meaningful differentiation on a scale reflecting type and amount of drug use. Such a scale was developed as a tool to facilitate research on the etiology of severe drug involvement among Navy drug abusers. The factors used for evaluating degree of drug involvement were: type of drug, maximum use rate, route of administration, age first used, and duration of involvement. First, by assigning a priori weights, then by application of linearization and empirical weighting methods, a quantitative involvement scale was constructed. This report describes the development of the scale and possible uses in drug rehabilitation research. METHOD Subjects. Ss were 590 active duty Navy and Marine Corps enlisted men examined upon entrance to the Naval Drug Rehabilitation Center (NDRC) , Miramar Naval Air Station, San Diego, California, between July and December, 1971. All chose to enter NDRC under conditions of exemption from prosecution because of illegal drug use. The average S was in his early twenties, in the lowest pay grades ( E 2 and E3), and Caucasian (88%). The demographic characteristics and drug histories of this population have been described in detail elsewhere (*).
Procedure. Because of the complexity of the procedures for constructing the involvement scale, the various steps are described in detail. The rationale for selecting and weighting each of the scoring components is presented below.
Type of Drug. The type of drug used is an obvious basis for differentiating drug users. For example, the incapacitating and physiological dependence effects of heroin generally are regarded aa far more severe than those of marijuana. Using this type of paired-comparison reasoning, eight categories of drugs were rank-ordered by the authors and given tentative weights in terms of the relative severity of their psychological and physiological effects. The rank-order of these drug categories from most to least severe and the initial weights assigned are shown in Table 1.
To independently aeaess the validity of this rank ordering, 20 physicians (16 psychiatrists and 4 non-psychiatrists) rated the same drug categories on 10-point scales according to the relative risk of physical and psychological dependence, mortality risk, and degree of impairment of normal physical and mental functions at the peak of drug action('). From the individual ratings, a mean score was derived for each drug, and these mean values are shown in Table 1. The physicians' ranking ry, Department of the Navy, under Reeearch Work Unit M1305.073009DFA5. %miom e x p a a r e those of the authors and are not to be construed 88 n d l y reflecting the o cial view or endorsement of the Departr ment of the Navy. The authors are indebted to Captain C. N. Pierozzi, Commandin 05cer Naval Drug Rehabilitation Center, Miramar, California, and to Comm+nden A. M. &&el the Senior Medical officer, for faciliteti reeearch efforta b the Navy Med~cal Neun, chiatnc Reeearch Unit. A special note of p b t s e is d to d. Doris Baaman and Mr. I &% Butler for anal-of data and to Ma. Lucde Cheng a n % . Patricia Pol& for typing and editing assistance. *Report Number 72-36, supported by the Bureau of W c i n e and S