Journal of Consulting and Clinical Psychology 1977, Vol. 45, No. 2, 222-227
Descriptive and Functional Classifications of Drug Abusers Albert S. Carlin and Fred F. Stauss Department of Psychiatry and Behavioral Sciences, University of Washington Polydrug (non-opiate-drug) abusers have previously been classified by a variety of typologies that can be characterized as either descriptive, functional, or a combination of both. This investigation proposes two objective scoring systems that classify polydrug users on a streetwise/straight dimension and on a selfmedication/recreational-use dimension. Both scoring systems agreed with clinical impressions for three samples drawn from three separate geographic locations. Streetwise self-medicators, straight self-medicators, and streetwise recreational users were compared on a variety of demographic variables and on the Minnesota Multiphasic Personality Inventory. The relationships found are discussed in terms of the implications of the categories for facilitating understanding of patterns of drug misuse and providing differential treatment strategies.
Clinical impressions indicate that the consumption of psychoactive drugs follows numerous patterns and serves a variety of functions. Classification of such patterns and functions can be roughly grouped into two categories: descriptive typologies and functional typologies. Descriptive typologies classify users by kind, amount, or pattern of drug use, or by some demographic or psychometric description. Functional typologies describe users by the purpose the drug serves the individuals. Growing out of experience with non-opiatedrug users, Wesson, Smith, and Lerner (197S) have descriptively categorized users as "streetwise" or "nonstreetwise." Basically, a streetwise individual is one who can maintain drug usage through reliance on other than societally sanctioned means. Streetwise and nonstreetwise are operationally defined by the means of funding drug use, legality of primary means of support, conventionality of dress and grooming, knowledge of street jargon, ability to buy drugs from street drug The research was supported in part by Grant 3 H81 DA 01476-OiSi from the National Institute of Drug Abuse. The authors thank James Berry, Grace Dammann, and Mick Kirby for providing additional data. Requests for reprints should be sent to Albert S. Carlin, Department of Psychiatry and Behavioral Sciences (RP-10), University of Washington, Seattle, Washington 98195.
dealers, and residence in a geographic area known as a youth drug subculture. A major contribution of the streetwise classification system is not only the articulation of criteria but the recognition of the existence of a nonstreetwise (straight) drug-abusing group. Statistical comparisons of the two groups demonstrated empirical differences in both psychological and demographic factors. Such results indicate that the two groups exist and that they are different. Although the streetwise dichotomy is an important insight, methodological difficulties exist. The primary problem is its boundedness to time and place. Definitions of dress, grooming habits, and living areas do not easily transfer from city to city or era to era. As such, this system is based on subjective judgments requiring familiarity with the individual and his environment. Despite these problems the empirical validation of this dichotomy demonstrated its value. Several authors have developed functional typologies for barbiturates and for amphetamines that describe drug users according to motivation. Chambers and Brill (1972) described three types of barbiturate abusers: (a) those who use barbiturates for their sedative effects to suppress anxiety and emotional distress; (b) those who use sedatives for their paradoxical disinhibiting effects; and (c) those who use barbiturates cyclically to counteract the effects of other drugs, par222
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
ticularly the amphetamines. Wesson and Smith (1973) delineated four types of barbiturate users that are very similar to those of Chambers and Brill, with the addition of the intravenous user, Shick, Smith, and Wesson (1972) also offer a fourfold functional classification of amphetamine users that is similar to the typologies applicable to barbiturate users. Chambers and Brill have also functionally dichotomized amphetamine abusers. They categorized abusers as adaptive abusers and escapist abusers. The functional classifications proposed by Chambers and Brill (1971), by Schick et al. (1972), and by Wesson and Smith (1973) are each based on descriptive data as well as motivation for drug usage. Consequently, these classifications are actually an admixture of functional and descriptive typologies. By eliminating the descriptive components, a more parsimonious classification of functional types can be distilled from the proposed typologies. The resulting functional typology consists of the two categories of self-medicators and recreational users. The streetwise/straight typology (streetwise typology) and the self-medication/recreational typology (self-medication typology) are theoretically independent dichotomies. Simultaneous use of both dichotomies allows individuals to be described both descriptively and functionally in a fashion that permits assessment of the relative importance of both dimensions. The advantage of using a 2 X 2 classification system is not only the increased parsimony of the system but the ability to merge and separate dimensions in order to better understand their interplay. This investigation tests the utility of these typologies with a two-step procedure. The first is the development and evaluation of predictive models based on objective criteria for the streetwise and self-medication typologies. The second step determines the utility of each typology by comparing psychometric and demographic data of members of each group. Study 1 Method Subjects. Three separate samples of polydrug (nonopiate) abusing patients were used to construct and validate the classification scheme. The largest
223
sample consisted of 141 individuals who applied for drug-related treatment at the Seattle Polydrug Center. This sample included 84 men, who averaged 25.27 years of age, and 57 women, who averaged 28.57 years of age. Additional samples of 42 and 20 patients were drawn from the case files of the San Francisco and Denver polydrug programs, respectively. The San Francisco sample consisted of 24 men and 18 women averaging 30.71 and 27.50 years of age, respectively, and the Denver sample included 15 men and 5 women who averaged 30.20 and 26.20 years of age, respectively. The age differences between centers failed to reach significance. All subjects misused stimulants, sedatives, or analgesics either singly or in combination. No individual had a primary problem with alcohol or heroin. The definition of misuse was a functional one based on the individual's self-report that drug use was problematic. Problems ranged from physical to psychological to legal.
Procedure All 141 subjects of the Seattle polydrug sample were subjectively dichotomized on each of the streetwise and self-medication dimensions. The Seattle treatment staff made these judgments by consensus based on life-style and patterns of drug use. The judgments assigned individuals to one of four possible categories: (a) straight self-medicating drug users, (b) straight recreational users, (c) streetwise recreational users; and (d) streetwise self-medicating users. Of the 141 subjects, 97 were considered to have extreme scores on both dimensions. These 97 subjects were used to develop a Bayesian prediction equation for each of the two typologies. Briefly defined, a Bayesian equation calculates the probability of an event occurring given known information (Edwards, Lindman, & Savage, 1963). In constructing such an equation, relevant variables were selected empirically. Contingency tables were constructed for each typology to compare the two poles of the typology on demographic variables describing social history, patterns of drug use, and social functioning. Those items that reached statistical significance of p < .10 were chosen to be included in the equations. Weights in the form of ratios were assigned to each variable based on the strength of the relationship of that variable to a given pole of the typology. The product of the individual weights divided by itself plus one results in the probability of being streetwise or the probability of being a selfmedicator (depending on the equation). 1 For each typology, an individual's score might range from .00 to 1.00. The initial prediction equations were applied to
p = - „,"{'., where p = probability and W\ = variable weight.
224
ALBERT S. CARL1N AND FRED F, STAUSS
the original 97 subjects to predict streetwise and selfmedication status. Weights of variables were adjusted and variables were eliminated from the equations until 100% accuracy was achieved for the 97 subjects on both typologies.2 To test the validity of the equation, the final Hayesian equations were used to predict the streetwise and self-medication status of the remaining 44 subjects of the Seattle sample. To determine whether the equation was peculiar to Seattle or whether it could generalize to other regions, it was applied to the patient samples drawn from the San Francisco and Denver polydrug programs. The predictions of the equations were compared to clinical judgments of staff members familiar with the given patient.
Table 1
Results
four categories contain significant numbers of subjects, the majority of subjects are in the streetwise recreational and straight self-medication cells. Despite different criteria and weights used in the two prediction equations, the streetwise and self-medication scores correlate at -.65 (/> < .01). Before eliminating subjects who received probability scores between .4 and .6, it was necessary to insure that the majority of subjects were not discarded. As indicated in Figure 1, both the streetwise and self-medication probability scores are markedly bimodal. The decision to eliminate subjects with midrange scores resulted in 17 subjects being eliminated. These subjects were almost equally likely to be eliminated by having either scale falling in the questionable range (10 subjects had midrange streetwise scores, 6 had midrange selfmedication scores, and 1 had midrange scores on both). Table 1 indicates that the greatest loss occurred in the two recreational-use cells. The straight recreational cell was essentially empty. Due to the minimal number of people in this cell, it was not included in the analysis. As a result, a one-way multivariate analysis of variance was conducted on the three remaining cells rather than the planned factorial multivariate analysis of variance. The remaining three cells were compared on six demographic variables. On these data, the multivariate analysis of variance attained significance, F(U, 224) = S.08, p < .01, as did five of the six univariate F scores (Table 2). The Student-Newman-Keuls procedure in-
Streetwise prediction. Agreement between staff ratings and computed prediction of streetwise status was reached for 41 of the 44 remaining Seattle patients. This level of agreement exceeds chance (sign test, p < .01). Eighty-six percent and 90% agreement were attained on the San Francisco and Denver patients, respectively. Both of these levels of agreement exceed chance (sign test, p < .01 for both). Self-medication predictions. Similar results were attained for prediction of self-medication. The equation agreed with clinical ratings on &4% of the Seattle sample. Denver and San Francisco clinical ratings agreed with the equation on &5% and 90% of patients, respectively. These levels of agreement exceed chance (p < .01, sign test). Study 2 Method Subjects. The subjects in this study were selected from the 141 subjects in the Seattle sample. Those subjects whose streetwise probability score or selfmedication probability score fell between .4 and .6 were eliminated to maximize group differences. This procedure yielded 124 subjects who could be clearly categorized by the equation along both dimensions. Procedure. The subjects were compared on the Minnesota Multiphasic Personality Inventory (MMPI) and demographic data not included in the Bayesian equations.
Results Application of both equations to the 141 Seattle subjects resulted in the distribution of subjects presented in Table 1. Although all
Frequencies of Self-medicating and Streetwise Polydrug, Users Be/ore and After 1'Mminntion of Midrange Subjects Group Streetwise Self-mcdicators Recreational users Straight Self-medicators Recreational users
Before
After 26 51
43 12
43 4
- The final variables and their associated weights are available from the authors.
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
225
8Ch
70-
|
| Streetwise
EH Self medication 60-
50
I
40-
|
30
20-
10-
_n£l
0- .101- .201- .301- .401- .501- .601- .701- .801- .901.100 .200 .300 .400 .500 .600 .700 .800 .900 1.00 Bayesian Probability Values Figure 1. Frequency distributions of streetwise and self-medication Bayesian probability values. dicated that the straight self-medicators differed from both streetwise groups on four of the five significant variables. The straight self-medicators differed from the streetwise self-medicators but not from the streetwise recreational users in the amount of education received. In general, the nonstreetwise user compared to the streetwise user is an older Table 2 Means of Demographic Variables Streetwise
Variable
Straight
Recreational users
Selfmedicators
Age" Age of first usea Previous psychiatric episodes Months employed out of 24« Education^ Arrests11
34.44 24.2.1
25.02 15.06
25.65 15.88
n
.7') 0.74 12.46 .35
Univariate /'' indicates p < .01. '> Univariate F indicates p < .05.
.902 5.5.! 11.69 7.00
1.27 4. OR 11.27 6.31
individual who begins using drugs later in life, has had fewer arrests, is better educated, and has a slightly better employment history. Similar multivariale analysis of variance and analysis of variance tests were conducted on the MMPI scores that were available for 77 of the 124 Seattle subjects who were clearly categorized. The results of these analyses are presented in Table 3. The overall multivariate analysis of variance, F(26, 120) = 2.02, p < .006, and three individual scales attained statistical significance. Individual MMPI scales reaching or approaching significance included F (p < .041), K (p < .023), D (p< .059), and Ma (p < .004). To determine the relative contribution of individual scales to the overall significance, the multivariate analysis of variance was rerun several times, dropping one additional variable each time. Variables were eliminated from the multivariate analysis of variance on the basis of their individual F scores, starting
226
ALBERT S. CARLIN AND FRED F. STAUSS
Table 3 Mean Minnesota Multiphasic Personality Inventory T Scores Stieetwise
Scale
1.
/,•** K** Us D*
II y I'd Ml' Pa Pi Sc
Ma*** Si
Straight
Recreational uscis
Selfmcdicators
47.56 67.56 51.28 62.48 80.44 71.68 75.92
45.71 75. 91 45.97 65.09 71.65 66.47 78.53
43.56 82.81 44.62 69.06 78.25 70.75 81.62
66.16 74.88 75.88 62.52 61.04
67.32 72.12 79.26 73.65 56.18
70.12 77.31 85.56 72.50 58.38
* p < .10. ** p < .01. *** p < .001.
with the highest score. Beginning with the Ma scale, this procedure was continued until the overall F score no longer reached significance. For this to occur, the following scales were dropped: L, F, K, D, Hy, Ma, and Si. The Student-Newman-Keuls procedure was performed on the F, K, and Ma scales. Straight self-medicators differed from both streetwise groups on K and Ma. The straight group also differed from the streetwise selfmedicators on the F scale. Overall, the streetwise users tended to score higher than the nonstreetwise users on both the MMPI validity and clinical scales. Discussion The results of this investigation indicate that polydrug abusers can be successfully dichotomized on streetwise and self-medication dimensions using a Bayesian equation based on objective data. Calculated values of group membership correlated highly with group membership assigned by subjective clinical judgment. This high degree of consistency was attained for data gathered at two geographically disparate polydrug programs as well as for subjects seen at the local polydrug program where the equations were developed. The cross-validation demonstrates that the predictions do not represent only local patterns of drug use but reflect general patterns. The scores for the Bayesian equations pro-
duce bimodal distributions for each dimension. These distributions suggest that the scoring systems do not merely produce cutoff points by which a normally distributed trait can be dichotomized but rather that each dimension is made up of two distinct subgroups. Although these distributions can be taken to indicate the marked differences between the subgroups of each dimension, they may be only artifacts of the equations. However, psychological and demographic differences between groups suggest that the distributions are not artifactual. In addition to developing and validating the streetwise and the self-medication classification schema, the study was designed to compare the subtypes within each of the two typologies and the interaction of the typologies. However, one cell of the resulting 2 X 2 matrix was essentially empty. As a result, analyses compared the straight self-medicator, the streetwise self-medicator, and the streetwise recreational user. The three groups differed significantly on both demographic and psychological test data. In comparing straight to street users, the straight user is an older individual who begins using drugs later in life and who has experienced fewer arrests than the streetwise individual. The straight group also has a better employment history than the streetwise group, despite both groups having a high level of unemployment. The psychological test data suggest that although neither the straight nor the street individual is pathologically defensive or vulnerable, the streetwise individual is more frank and more open to admitting problems than is the straight individual. The streetwise users are also seen as impulsive with a level of activity that can be maladaptive. The addition of the self-medication factor to the streetwise factor produces a finer level of differentiation, which then highlights differences on additional variables. The straight self-medicating individual is better educated and less deviant (or perhaps less frank) than the streetwise self-medicating individual, whereas the streetwise social/recreational users fall between these two groups and differ from neither. Finally, a tendency exists for the straight self-medicator to acknowledge
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
more depressive affect than the streetwise individual. Generalizing from these data, the straight self-medicating individual compared to the streetwise individual at the time that treatment is sought is more functional, has a slightly better premorbid history, and has been involved with drugs for approximately the same length of time but started using drugs later in life. Of the streetwise group, the recreational user tends to be less disordered than the self-medicating individual. The absence of significant numbers of straight recreational users prevented the evaluation of the utility of simultaneous application of the two classification schema. The high correlation between the two typologies even raises the question of their independence. This correlation may be interpreted as an artifact of the equation such as item overlap or as a true relationship between the two typologies. No empirical evidence is available to resolve this question. Recognition of the differences between the three groups raises questions about the appropriateness of drug treatment programs that view drug misuse as a primary symptom. Focusing only on the behavior of drug use results in an unwarranted assumption of similarity of many drug behaviors and ignores some profound differences. Even though the streetwise counselor may have empathetic insight into a streetwise drug user, his experiences and world view may differ markedly
227
from a welfare mother attempting to selfmedicate with sedatives, and the counselor may miss the streetwise individual's attempt to ward off psychotic ideation through a high rate of amphetamine use. A major contribution of this research is an objective, reliable, and valid classification schema. Also, the data of this study indicated that subtypes of polydrug users exist, and the nature of their differences suggests that differing diagnoses and treatment strategies are required for each group. Additional research is needed to further test the utility of the classification system, to elaborate on differences between groups, and to pursue the implications of these differences for treatment. References Chambers, C. D., & Brill, L. Some considerations for the treatment, of non-narcotic drug abusers. Industrial Medicine, 1971, 40, 29-38. Edwards, W., Lindman, II., & Savage, L. J. Baycsian statistical inference for psychological research. Psychological Review, 1963, 70, 193-242. Shick, J. F. E., Smith, D. E., & Wesson, D. R. An analysis of amphetamine toxicity and patterns of use. Journal of Psychedelic Drugs, 1972, 5, 113-130. Wesson, D. R., & Smith, D. E. Barbiturate toxicity and the treatment of barbiturate dependence. In D. E. Smith & D. R. Wesson (Eds.), Uppers and downers. Englewood Cliffs, N.J.: Prentice-Hall, 1973. Wesson, D. R., Smith, D. E., & Lcrner, S. E. Streetwise and nonstrcetwise polydrug typology: Myth or reality? Journal of Psychedelic. Drugs, 1975, 7, 121-134.
Received February 9, 1976 •
Descriptive and Functional Classifications of Drug Abusers Albert S. Carlin and Fred F. Stauss Department of Psychiatry and Behavioral Sciences, University of Washington Polydrug (non-opiate-drug) abusers have previously been classified by a variety of typologies that can be characterized as either descriptive, functional, or a combination of both. This investigation proposes two objective scoring systems that classify polydrug users on a streetwise/straight dimension and on a selfmedication/recreational-use dimension. Both scoring systems agreed with clinical impressions for three samples drawn from three separate geographic locations. Streetwise self-medicators, straight self-medicators, and streetwise recreational users were compared on a variety of demographic variables and on the Minnesota Multiphasic Personality Inventory. The relationships found are discussed in terms of the implications of the categories for facilitating understanding of patterns of drug misuse and providing differential treatment strategies.
Clinical impressions indicate that the consumption of psychoactive drugs follows numerous patterns and serves a variety of functions. Classification of such patterns and functions can be roughly grouped into two categories: descriptive typologies and functional typologies. Descriptive typologies classify users by kind, amount, or pattern of drug use, or by some demographic or psychometric description. Functional typologies describe users by the purpose the drug serves the individuals. Growing out of experience with non-opiatedrug users, Wesson, Smith, and Lerner (197S) have descriptively categorized users as "streetwise" or "nonstreetwise." Basically, a streetwise individual is one who can maintain drug usage through reliance on other than societally sanctioned means. Streetwise and nonstreetwise are operationally defined by the means of funding drug use, legality of primary means of support, conventionality of dress and grooming, knowledge of street jargon, ability to buy drugs from street drug The research was supported in part by Grant 3 H81 DA 01476-OiSi from the National Institute of Drug Abuse. The authors thank James Berry, Grace Dammann, and Mick Kirby for providing additional data. Requests for reprints should be sent to Albert S. Carlin, Department of Psychiatry and Behavioral Sciences (RP-10), University of Washington, Seattle, Washington 98195.
dealers, and residence in a geographic area known as a youth drug subculture. A major contribution of the streetwise classification system is not only the articulation of criteria but the recognition of the existence of a nonstreetwise (straight) drug-abusing group. Statistical comparisons of the two groups demonstrated empirical differences in both psychological and demographic factors. Such results indicate that the two groups exist and that they are different. Although the streetwise dichotomy is an important insight, methodological difficulties exist. The primary problem is its boundedness to time and place. Definitions of dress, grooming habits, and living areas do not easily transfer from city to city or era to era. As such, this system is based on subjective judgments requiring familiarity with the individual and his environment. Despite these problems the empirical validation of this dichotomy demonstrated its value. Several authors have developed functional typologies for barbiturates and for amphetamines that describe drug users according to motivation. Chambers and Brill (1972) described three types of barbiturate abusers: (a) those who use barbiturates for their sedative effects to suppress anxiety and emotional distress; (b) those who use sedatives for their paradoxical disinhibiting effects; and (c) those who use barbiturates cyclically to counteract the effects of other drugs, par222
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
ticularly the amphetamines. Wesson and Smith (1973) delineated four types of barbiturate users that are very similar to those of Chambers and Brill, with the addition of the intravenous user, Shick, Smith, and Wesson (1972) also offer a fourfold functional classification of amphetamine users that is similar to the typologies applicable to barbiturate users. Chambers and Brill have also functionally dichotomized amphetamine abusers. They categorized abusers as adaptive abusers and escapist abusers. The functional classifications proposed by Chambers and Brill (1971), by Schick et al. (1972), and by Wesson and Smith (1973) are each based on descriptive data as well as motivation for drug usage. Consequently, these classifications are actually an admixture of functional and descriptive typologies. By eliminating the descriptive components, a more parsimonious classification of functional types can be distilled from the proposed typologies. The resulting functional typology consists of the two categories of self-medicators and recreational users. The streetwise/straight typology (streetwise typology) and the self-medication/recreational typology (self-medication typology) are theoretically independent dichotomies. Simultaneous use of both dichotomies allows individuals to be described both descriptively and functionally in a fashion that permits assessment of the relative importance of both dimensions. The advantage of using a 2 X 2 classification system is not only the increased parsimony of the system but the ability to merge and separate dimensions in order to better understand their interplay. This investigation tests the utility of these typologies with a two-step procedure. The first is the development and evaluation of predictive models based on objective criteria for the streetwise and self-medication typologies. The second step determines the utility of each typology by comparing psychometric and demographic data of members of each group. Study 1 Method Subjects. Three separate samples of polydrug (nonopiate) abusing patients were used to construct and validate the classification scheme. The largest
223
sample consisted of 141 individuals who applied for drug-related treatment at the Seattle Polydrug Center. This sample included 84 men, who averaged 25.27 years of age, and 57 women, who averaged 28.57 years of age. Additional samples of 42 and 20 patients were drawn from the case files of the San Francisco and Denver polydrug programs, respectively. The San Francisco sample consisted of 24 men and 18 women averaging 30.71 and 27.50 years of age, respectively, and the Denver sample included 15 men and 5 women who averaged 30.20 and 26.20 years of age, respectively. The age differences between centers failed to reach significance. All subjects misused stimulants, sedatives, or analgesics either singly or in combination. No individual had a primary problem with alcohol or heroin. The definition of misuse was a functional one based on the individual's self-report that drug use was problematic. Problems ranged from physical to psychological to legal.
Procedure All 141 subjects of the Seattle polydrug sample were subjectively dichotomized on each of the streetwise and self-medication dimensions. The Seattle treatment staff made these judgments by consensus based on life-style and patterns of drug use. The judgments assigned individuals to one of four possible categories: (a) straight self-medicating drug users, (b) straight recreational users, (c) streetwise recreational users; and (d) streetwise self-medicating users. Of the 141 subjects, 97 were considered to have extreme scores on both dimensions. These 97 subjects were used to develop a Bayesian prediction equation for each of the two typologies. Briefly defined, a Bayesian equation calculates the probability of an event occurring given known information (Edwards, Lindman, & Savage, 1963). In constructing such an equation, relevant variables were selected empirically. Contingency tables were constructed for each typology to compare the two poles of the typology on demographic variables describing social history, patterns of drug use, and social functioning. Those items that reached statistical significance of p < .10 were chosen to be included in the equations. Weights in the form of ratios were assigned to each variable based on the strength of the relationship of that variable to a given pole of the typology. The product of the individual weights divided by itself plus one results in the probability of being streetwise or the probability of being a selfmedicator (depending on the equation). 1 For each typology, an individual's score might range from .00 to 1.00. The initial prediction equations were applied to
p = - „,"{'., where p = probability and W\ = variable weight.
224
ALBERT S. CARL1N AND FRED F, STAUSS
the original 97 subjects to predict streetwise and selfmedication status. Weights of variables were adjusted and variables were eliminated from the equations until 100% accuracy was achieved for the 97 subjects on both typologies.2 To test the validity of the equation, the final Hayesian equations were used to predict the streetwise and self-medication status of the remaining 44 subjects of the Seattle sample. To determine whether the equation was peculiar to Seattle or whether it could generalize to other regions, it was applied to the patient samples drawn from the San Francisco and Denver polydrug programs. The predictions of the equations were compared to clinical judgments of staff members familiar with the given patient.
Table 1
Results
four categories contain significant numbers of subjects, the majority of subjects are in the streetwise recreational and straight self-medication cells. Despite different criteria and weights used in the two prediction equations, the streetwise and self-medication scores correlate at -.65 (/> < .01). Before eliminating subjects who received probability scores between .4 and .6, it was necessary to insure that the majority of subjects were not discarded. As indicated in Figure 1, both the streetwise and self-medication probability scores are markedly bimodal. The decision to eliminate subjects with midrange scores resulted in 17 subjects being eliminated. These subjects were almost equally likely to be eliminated by having either scale falling in the questionable range (10 subjects had midrange streetwise scores, 6 had midrange selfmedication scores, and 1 had midrange scores on both). Table 1 indicates that the greatest loss occurred in the two recreational-use cells. The straight recreational cell was essentially empty. Due to the minimal number of people in this cell, it was not included in the analysis. As a result, a one-way multivariate analysis of variance was conducted on the three remaining cells rather than the planned factorial multivariate analysis of variance. The remaining three cells were compared on six demographic variables. On these data, the multivariate analysis of variance attained significance, F(U, 224) = S.08, p < .01, as did five of the six univariate F scores (Table 2). The Student-Newman-Keuls procedure in-
Streetwise prediction. Agreement between staff ratings and computed prediction of streetwise status was reached for 41 of the 44 remaining Seattle patients. This level of agreement exceeds chance (sign test, p < .01). Eighty-six percent and 90% agreement were attained on the San Francisco and Denver patients, respectively. Both of these levels of agreement exceed chance (sign test, p < .01 for both). Self-medication predictions. Similar results were attained for prediction of self-medication. The equation agreed with clinical ratings on &4% of the Seattle sample. Denver and San Francisco clinical ratings agreed with the equation on &5% and 90% of patients, respectively. These levels of agreement exceed chance (p < .01, sign test). Study 2 Method Subjects. The subjects in this study were selected from the 141 subjects in the Seattle sample. Those subjects whose streetwise probability score or selfmedication probability score fell between .4 and .6 were eliminated to maximize group differences. This procedure yielded 124 subjects who could be clearly categorized by the equation along both dimensions. Procedure. The subjects were compared on the Minnesota Multiphasic Personality Inventory (MMPI) and demographic data not included in the Bayesian equations.
Results Application of both equations to the 141 Seattle subjects resulted in the distribution of subjects presented in Table 1. Although all
Frequencies of Self-medicating and Streetwise Polydrug, Users Be/ore and After 1'Mminntion of Midrange Subjects Group Streetwise Self-mcdicators Recreational users Straight Self-medicators Recreational users
Before
After 26 51
43 12
43 4
- The final variables and their associated weights are available from the authors.
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
225
8Ch
70-
|
| Streetwise
EH Self medication 60-
50
I
40-
|
30
20-
10-
_n£l
0- .101- .201- .301- .401- .501- .601- .701- .801- .901.100 .200 .300 .400 .500 .600 .700 .800 .900 1.00 Bayesian Probability Values Figure 1. Frequency distributions of streetwise and self-medication Bayesian probability values. dicated that the straight self-medicators differed from both streetwise groups on four of the five significant variables. The straight self-medicators differed from the streetwise self-medicators but not from the streetwise recreational users in the amount of education received. In general, the nonstreetwise user compared to the streetwise user is an older Table 2 Means of Demographic Variables Streetwise
Variable
Straight
Recreational users
Selfmedicators
Age" Age of first usea Previous psychiatric episodes Months employed out of 24« Education^ Arrests11
34.44 24.2.1
25.02 15.06
25.65 15.88
n
.7') 0.74 12.46 .35
Univariate /'' indicates p < .01. '> Univariate F indicates p < .05.
.902 5.5.! 11.69 7.00
1.27 4. OR 11.27 6.31
individual who begins using drugs later in life, has had fewer arrests, is better educated, and has a slightly better employment history. Similar multivariale analysis of variance and analysis of variance tests were conducted on the MMPI scores that were available for 77 of the 124 Seattle subjects who were clearly categorized. The results of these analyses are presented in Table 3. The overall multivariate analysis of variance, F(26, 120) = 2.02, p < .006, and three individual scales attained statistical significance. Individual MMPI scales reaching or approaching significance included F (p < .041), K (p < .023), D (p< .059), and Ma (p < .004). To determine the relative contribution of individual scales to the overall significance, the multivariate analysis of variance was rerun several times, dropping one additional variable each time. Variables were eliminated from the multivariate analysis of variance on the basis of their individual F scores, starting
226
ALBERT S. CARLIN AND FRED F. STAUSS
Table 3 Mean Minnesota Multiphasic Personality Inventory T Scores Stieetwise
Scale
1.
/,•** K** Us D*
II y I'd Ml' Pa Pi Sc
Ma*** Si
Straight
Recreational uscis
Selfmcdicators
47.56 67.56 51.28 62.48 80.44 71.68 75.92
45.71 75. 91 45.97 65.09 71.65 66.47 78.53
43.56 82.81 44.62 69.06 78.25 70.75 81.62
66.16 74.88 75.88 62.52 61.04
67.32 72.12 79.26 73.65 56.18
70.12 77.31 85.56 72.50 58.38
* p < .10. ** p < .01. *** p < .001.
with the highest score. Beginning with the Ma scale, this procedure was continued until the overall F score no longer reached significance. For this to occur, the following scales were dropped: L, F, K, D, Hy, Ma, and Si. The Student-Newman-Keuls procedure was performed on the F, K, and Ma scales. Straight self-medicators differed from both streetwise groups on K and Ma. The straight group also differed from the streetwise selfmedicators on the F scale. Overall, the streetwise users tended to score higher than the nonstreetwise users on both the MMPI validity and clinical scales. Discussion The results of this investigation indicate that polydrug abusers can be successfully dichotomized on streetwise and self-medication dimensions using a Bayesian equation based on objective data. Calculated values of group membership correlated highly with group membership assigned by subjective clinical judgment. This high degree of consistency was attained for data gathered at two geographically disparate polydrug programs as well as for subjects seen at the local polydrug program where the equations were developed. The cross-validation demonstrates that the predictions do not represent only local patterns of drug use but reflect general patterns. The scores for the Bayesian equations pro-
duce bimodal distributions for each dimension. These distributions suggest that the scoring systems do not merely produce cutoff points by which a normally distributed trait can be dichotomized but rather that each dimension is made up of two distinct subgroups. Although these distributions can be taken to indicate the marked differences between the subgroups of each dimension, they may be only artifacts of the equations. However, psychological and demographic differences between groups suggest that the distributions are not artifactual. In addition to developing and validating the streetwise and the self-medication classification schema, the study was designed to compare the subtypes within each of the two typologies and the interaction of the typologies. However, one cell of the resulting 2 X 2 matrix was essentially empty. As a result, analyses compared the straight self-medicator, the streetwise self-medicator, and the streetwise recreational user. The three groups differed significantly on both demographic and psychological test data. In comparing straight to street users, the straight user is an older individual who begins using drugs later in life and who has experienced fewer arrests than the streetwise individual. The straight group also has a better employment history than the streetwise group, despite both groups having a high level of unemployment. The psychological test data suggest that although neither the straight nor the street individual is pathologically defensive or vulnerable, the streetwise individual is more frank and more open to admitting problems than is the straight individual. The streetwise users are also seen as impulsive with a level of activity that can be maladaptive. The addition of the self-medication factor to the streetwise factor produces a finer level of differentiation, which then highlights differences on additional variables. The straight self-medicating individual is better educated and less deviant (or perhaps less frank) than the streetwise self-medicating individual, whereas the streetwise social/recreational users fall between these two groups and differ from neither. Finally, a tendency exists for the straight self-medicator to acknowledge
DESCRIPTIVE AND FUNCTIONAL CLASSIFICATIONS OF DRUG ABUSERS
more depressive affect than the streetwise individual. Generalizing from these data, the straight self-medicating individual compared to the streetwise individual at the time that treatment is sought is more functional, has a slightly better premorbid history, and has been involved with drugs for approximately the same length of time but started using drugs later in life. Of the streetwise group, the recreational user tends to be less disordered than the self-medicating individual. The absence of significant numbers of straight recreational users prevented the evaluation of the utility of simultaneous application of the two classification schema. The high correlation between the two typologies even raises the question of their independence. This correlation may be interpreted as an artifact of the equation such as item overlap or as a true relationship between the two typologies. No empirical evidence is available to resolve this question. Recognition of the differences between the three groups raises questions about the appropriateness of drug treatment programs that view drug misuse as a primary symptom. Focusing only on the behavior of drug use results in an unwarranted assumption of similarity of many drug behaviors and ignores some profound differences. Even though the streetwise counselor may have empathetic insight into a streetwise drug user, his experiences and world view may differ markedly
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from a welfare mother attempting to selfmedicate with sedatives, and the counselor may miss the streetwise individual's attempt to ward off psychotic ideation through a high rate of amphetamine use. A major contribution of this research is an objective, reliable, and valid classification schema. Also, the data of this study indicated that subtypes of polydrug users exist, and the nature of their differences suggests that differing diagnoses and treatment strategies are required for each group. Additional research is needed to further test the utility of the classification system, to elaborate on differences between groups, and to pursue the implications of these differences for treatment. References Chambers, C. D., & Brill, L. Some considerations for the treatment, of non-narcotic drug abusers. Industrial Medicine, 1971, 40, 29-38. Edwards, W., Lindman, II., & Savage, L. J. Baycsian statistical inference for psychological research. Psychological Review, 1963, 70, 193-242. Shick, J. F. E., Smith, D. E., & Wesson, D. R. An analysis of amphetamine toxicity and patterns of use. Journal of Psychedelic Drugs, 1972, 5, 113-130. Wesson, D. R., & Smith, D. E. Barbiturate toxicity and the treatment of barbiturate dependence. In D. E. Smith & D. R. Wesson (Eds.), Uppers and downers. Englewood Cliffs, N.J.: Prentice-Hall, 1973. Wesson, D. R., Smith, D. E., & Lcrner, S. E. Streetwise and nonstrcetwise polydrug typology: Myth or reality? Journal of Psychedelic. Drugs, 1975, 7, 121-134.
Received February 9, 1976 •
