Impulsiveness and subjective effects of intravenous cocaine administration in the laboratory

Journal of Substance Abuse, 6, 355-366 (1994)

Impulsiveness and Subjective Effects of Intravenous Cocaine Administration

in the Laboratory

Nicola G. Cascella University of Milan

Craig T. Nagoshi Arizona State University

Caries Muntaner National Institute of Mental Health

Daniel Walter Philadelphia Veterans Administration Medical Center

Charles A. Haertzen National Institute on Drug Abuse Addiction Research Center

Karen M. Kumor Philadelphia Veterans Administration Medical Center

Cardiovascular and subjective responses to placebo and 40-mg intravenous (iv) cocaine injections were measured in 29 male iv cocaine users: most subjects received each of these injections on two separate occasions. Most of the subjects also completed various measures of psychopathology and personality. Although the small sample size made any conclusions tentative, an expected significant association between impulsivity and subjective euphoria following 40-mg cocaine administration was obtained, whereas associations of personality measures with cardiovascular responses to cocaine administration were inconsistent.

T h e interaction between psychoactive drugs and personality is o f interest both with respect to the way drugs can change behavior a long the axes def ining personality (H.J. Eysenck, 1983; Garau & Garcia-Sevilla, 1986; Garcia Sevilla, 1984) and along the lines personality may determine the way drugs affect behavior (Anderson & Revelle, 1982; M.W. Eysenck & Folkard, 1980; B.S. Gupta & Gupta, 1984; U. Gupta, 1984).

Correspondence and requests for reprints should be sent to Craig T. Nagoshi, Department of Psychology, Arizona State University, Tempe, AZ 85287.

355

356 N.G. Cascella, C.T. Nagoshi, C. Muntaner, D. Walter, C.A. Haertzen, and K.M. Kumor

Drug-induced subjective effects have been found to be good indicators of abuse potential (Schuster, Fischman, & Johanson, 1981), but very few studies (Haer- tzen & Hooks, 1969) have been devoted to the relation between drug-induced subjective effects and dimensional personality theories. Recent investigations (Chait, Uhlenhuth, & Johanson, 1989; de Wit, Pierri, & Johanson, 1989; de Wit, Uhlenhuth, & Johanson, 1986; de Wit, Uhlenhuth, Pierri & Johanson, 1987; Nagoshi, Wilson, & Rodriguez, 1991) have rekindled the scientific interest about the role played by individual differences in sensitivity to human self- administered drugs and by personality dimensions over drug effects.

Nonhuman laboratory studies (Spear, Muntaner, Goldberg, & Katz, 1991) and the last decade's "epidemic" (Kozel & Adams, 1986) have demonstrated the high abuse liability of cocaine. Thus, it appears scientifically compelling to un- derstand the determinants of cocaine-seeking and cocaine-taking behavior. This study was aimed at testing the hypothesis that specific personality dimensions, as assessed by self-administered questionnaires, are predictive of the degree of intensity of cocaine-induced subjective effects in experienced users administered intravenous (iv) cocaine. We were expecting that high impulsive subjects, who are thought to be characterized by a low level of arousal (H.J. Eysenck, 1983) and high sensitivity to signals of reward (Gray, 1981), would report a higher intensity of subjective effects. Measures of psychopathology and aggression also were assessed with regard to subjective and cardiovascular responses to placebo and 40- mg iv cocaine administration.

METHOD

Sample

The data for these analyses were obtained from 29 male volunteers, 21-43 years old, who participated in one of four studies on cardiovascular and subjective responses to iv cocaine administration. Variations in the cocaine administration procedures and in the administration and composition of the psychometric test battery across the four studies, as well as missing data due to instrument failures, loss of records, and subject dropout, however, resulted in no subjects having been tested on all of the measures to be analyzed. In fact, the sample sizes for all analyses are considerably reduced, a serious problem that will be discussed later.

All subjects had a history of iv cocaine use. Twenty-two subjects had used cocaine in the 2 weeks preceding participation in the study. The remaining subjects had used cocaine in the 3 months preceding recruitment. Average reported frequency of cocaine use was 12 days per month and average reported quantity of use was 0.70 g/day of street cocaine (50% purity in the Baltimore area, based on Drug Enforcement Agency analysis of seized drug), with little intersubject variability. In addition to cocaine, 60% of subjects had a history of use of opiates, minor tranquilizers, marijuana, and hallucinogens (from one to several times in their lifetime). All subjects reported use of alcohol and tobacco and a minimum raw score of 18 on the vocabulary part of the Shipley-Hartford Retreat Scale

Effects of Intravenous Cocaine 357

(Shipley, 1940). A past history of psychiatric diagnosis did not exclude subjects fi'om the study.

Subjects resided on a research ward during the screening procedures and subsequent study to ensure compliance and to prevent self-administration of drugs that were not allowed. Nicotine (cigarettes), caffeine (beverages), and cocaine (in the study) were the only drugs allowed. Random screening of ur~a~ samples demonstrated no use of illicit drugs other than cocaine, which w a ~ . ~ ministered as part of the study protocols. All subjects gave informed consZ~l~t in compliance with guidelines of the institutional review boards of the Johns Hop- kins Hospital and Francis Scott Key Medical Center, Baltimore, Maryland.

Procedure

The data reported here are partially taken from a series of four studies (Kumor, Sherer, Gomez, Cone, & Jaffe, 1989; Kumor, Sherer, & Jaffe, 1989; London et al., 1990; Muntaner, Kumor, Nagoshi, & Jaffe, 1991; Sherer, Kumor, Mahaffey, Cone, &Jaffe, 1988) in which iv injections of cocaine (40 mg) or placebo (receiving saline and expecting cocaine) were administered as positive and negative controls in experiments that were primarily designed to study drug tolerance and drug interactions. As part of those studies, due to the inherent dangers of cocaine administration (Cregler & Mark, 1986), it was necessary to administer a series of single iv infusions of cocaine for safety screening. During these sessions, the 40-mg cocaine and the placebo were administered in a pseu- dorandomized fashion, such that 20-mg iv cocaine always preceded 40-mg iv cocaine. There was a minimum of 48 hours between experimental sessions. In Table 1 these administrations are indicated as Placebo 1 and 40-mg Cocaine 1. If no untoward effects were noted, subjects entered the randomized double-blind part of the study. The 40-mg cocaine and the placebo injections administered at this time are referred to in Table 1 as 40-mg Cocaine 2 and Placebo 2.

Measures

For more information about the administration and psychometric properties of the DIS, SCL-90R, IVE, and B - D used with the Addiction Research Center sample, see Muntaner et al. (1990) and Walter, Nagoshi, Muntaner, and Haer- tzen (1990). Table 1 presents the means and standard deviations on the various measures for the sample, and t values and statistical significance of post- versus preinjection cocaine responses.

Diagnostic Interview Schedule (DIS) The DIS (Robins, Helzer, Croughan, Williams, & Spitzer, 1981) is designed to

yield Diagnostic and Statistical Manual of Mental Disorders (DSM-III; American Psychiatric Association, 1980) diagnoses of the lifetime occurrence of psychopathology. These diagnoses were made on self-reports obtained on a computerized version of the DIS. Besides drug abuse/dependence diagnoses,

Table 1. Means a n d S t a n d a r d Dev ia t ions o f S a m p l e

Measure n M SD t"

Post- Minus Precocaine Injection Scores Systolic blood pressure

Placebo 1 Placebo 2 40-rag Cocaine 40-mg Cocaine

Diastolic blood pressure Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine

Pulse Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine

Feel the drug Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine 2

Feel high Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine 2

Feel rush Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine 2

Feel good Placebo 1 Placebo 2 40-mg Cocaine 40-mg Cocaine 2

Feel anxious Placebo 1 Placebo 2 40-mg Cocaine 1 40-mg Cocaine 2

SCL-90R Total T Score

DIS-ASP

Eysenck IVE Impulsiveness Venturesomeness Empathy

Buss-Durkee Hostility Inventory Behavior Attitude

20' 1.95 7.10 - 1.23 21 11.95 15.93 -3 .44** 23 18.87 18.39 -4 .92*** 23 24.70 20.06 -5 .91"**

20 0.55 8.13 -0 .30 21 4.05 8.30 -2 .23* 23 13.39 12.87 -4 .99*** 23 9.74 11.40 -4 .10"**

20 2.15 6.55 - 1.47 22 6.32 12.93 -2 .29* 23 21.09 17.15 -5 .90*** 23 24.17 17.76 -6 .53***

20 0.55 0.94 -2 .60* 29 0.21 0.41 -2 .76** 19 2.00 1.49 -5 .85*** 26 1.92 1.09 -8 .97***

17 0.23 0.44 -2 .22* 18 0.22 0.43 -2 .20* 16 1.87 1.50 -5 .00*** 15 1.80 1.21 -5 .78***

23 0.24 0.52 -2 .25* 29 0.38 1.07 - 1.9 I 22 2.23 1.53 -6 .86*** 26 1.99 1.73 -5 .85***

23 -0 .62 1.24 2.41 * 29 0.14 1.26 -0.61 22 0.32 1.55 -0 .96 26 1.11 1.95 -2 .90**

23 0.16 0.55 - 1.35 29 0.05 0.92 -0 .29 22 1.00 1.52 -3 .08** 23 1.03 1.49 -3.31 **

17 40.06 10.29

24 1.12 0.68

12 8.92 4.99 12 10.42 3.06 12 13.58 2.64

18 19.78 7.30 18 13.44 5.26

aPaired t test of pre- versus postinjection scores. *p < .05. **p < .01. ***p < .001.


antisocial personality disorder (ASP) was the most prevalent diagnosis in this sample. ASP was coded as no symptoms (0), symptoms (1), or full diagnosis (2). As compared to the related diagnosis of psychopathy (Hare, 1983), the ASP diagnosis places more emphasis on delinquent and criminal behavior and less on personality traits (Hare, 1983).

Symptom Check List, Revised (SCL-90R) The SCL-90R (Derogatis, 1975) is a 90-item self-report measure of current

psychopathology. Although scored to produce a priori scales for somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism, these scales are highly correlated in our sample. The mean t score for the General Severity Index (total symptoms multiplied by intensity of distress) is retained in this analysis as a glob- al measure of current psychopathology.

Impulsivity-Venturesomeness-Empathy (IVE) The IVE (S.B.G. Eysenck & Eysenck, 1978; S.B.G. Eysenck, Pearson, Easting

& Allsopp, 1985) is a 54-item self-report questionnaire. It generates a priori scales of Impulsivity, reflective of poor behavioral controls and lack of ability to delay gratification; Venturesomeness, reflective of sensation seeking and sociability; and Empathy, reflective of sensitivity to the feelings and reactions of others and susceptibility to social cues. Alpha reliabilities calculated on 276 subjects at the Addiction Research Center and representative of our study sample, were .82 for the 19-item Impulsivity scale, .79 for the 16-item Venturesomeness scale, and .66 for the 19-item Empathy scale.

Buss-Durkee Hostility Inventory (B-D) The B-D (Buss & Durkee, 1957) is a self-report measure of different forms of

aggressive behavior and cognitive sets. It generates a priori subscales for assault, indirect aggression, irritability, verbal hostility, resentment, suspicion, negativ- ism, and guilt. A principal component analysis of the scale for 277 subjects who completed this measure (Walter et al., 1990) yielded two components with eigen- values greater than 1.0 and accounted for 61.6% of the variance. Varimax rota- tion of these components yielded factors clearly representing aggressive "behavior" versus hostile "attitude."

Cocaine Sensitive Scale (CSS) The CSS (London et al., 1990; Muntaner, Cascella, et al., 1989; Muntaner,

Kumor, Nagoshi, & Jaffe, 1989) is a 23-item rating scale used as a measure of subjective effects commonly reported by cocaine users. The items were rated on 5- or 10-point rating scales depending on the study, and the scales were stan- dardized across studies for these analyses (Nagoshi, Kumor, & Muntaner, 1992). The items used in the CSS demonstrate adequate validity when assessed against other standard subjective drug effects measures and in the measure's sensitivity to cocaine effects (Kumor, Sherer, & Cascella, 1989; Sherer, 1988; Sherer et al., 1988).


Cardiovascular Measures During the 30 min after the test conlpound infusion, subjects' blood pressure

and pulse rate were periodically measured. Blood pressure (systolic and diastolic) and heart rate were sampled by a BARD Biomedical Sentron automated blood pressure monitor. The cocaine responses analyzed here were taken at 10 min before and 2 min after each administration of placebo or cocaine.

RESULTS

Table 2 presents the correlations of the SCL-90R total, DIS-ASP, IVE Impul- sivity, Venturesomeness, and Empathy, and Buss-Durkee Hostile Behavior and Attitude scores with cardiovascular and subjective responses to placebo and 40- mg iv cocaine administrations. Cocaine responses were computed by subtracting the first postinjection score fi'om the preinjection baseline score for each subject. Pairwise deletion of missing data was used for Table 2, and as noted previously, sample sizes fluctuated due to variations in the procedures across the four studies, subject dropouts, and loss of data due to equipment malfunctions or pro- cedural oversights.

All of the correlations show in Table 2 are notably unstable due to the small sample sizes. Given the 84 correlations in the table between the seven psychometric measures and the 12 cardiovascular responses to cocaine, 4 would be expected to be significant by chance at the .05 alpha level, if the correlations were independent. The 6 significant correlations found are neither consistent nor readily interpretable across different cocaine administrations and appear likely to be chance effects.

Given the 140 correlations in the table between the seven psychometric measures and the 20 subjective responses to cocaine, 7 would be expected to be significant by chance at the .05 alpha level. For the 10 significant correlations found for these latter responses, however, there were some consistencies appar- ent, with higher IVE Impulsivity, as expected, being a relatively consistently significant predictor of enhanced euphoric responses (feel high, feel good) to 40 mg cocaine. Similar nonsignificant trends were found for the related subjective response of "feel drug," although not for "feel rush." Because impulsivity has been found to be significantly correlated with Buss-Durkee behavioral and atti- tudinal hostility (but not antisocial personality for this group of subjects; see Walter et al., 1990), it is somewhat surprising that the feel high and feel good effects found for impulsivity were not found for the Buss-Durkee scales. The patterns of correlations were not much altered, however, when the analyses were restricted just to that subset of subjects with IVE data. The other inconsistent and basically uninterpretable correlations of the psychometric measures with subjective cocaine responses are probably chance effects.

DISCUSSION

Given the small sample sizes, these results are at best suggestive, but the sparsity of data on iv cocaine responses in humans argues for the importance of the


findings. Previous analyses of the stability of cardiovascular and subjective responses to placebo and 40-mg iv cocaine over time (Nagoshi et al., 1992) suggested that subjective responses were relatively stable, particularly under placebo administration, even though cardiovascular responses to cocaine tended to vary from day to day. It was suggested that this stability was the result of learned expectancies of drug effects. These findings support the notion that personality may be an important determinant of subjective responses to cocaine, and one could make a case that the sensitivity to reward cues associated with impulsivity might, in fact, lead to expectancies of greater drug effects. These expectancies may then affect subjective perceptions of these effects after drug administration.

Previous experiments on individual differences in the discriminative stimulus effects (Chait et al., 1989) and reinforcing functions (de Wit et al., 1986) of amphetamine, demonstrated that amphetamine had a greater effect for discrim- inators and choosers on ratings of drug liking or positive mood and euphoria. Similar results were obtained in response to alcohol administration (de Wit et al., 1987). Furthermore, in two of those studies (Chait et al., 1989; de Wit et al., 1986), subjects who most liked and chose the drugs scored higher on personality measures of extraversion and disinhibition. On the other hand, Nagoshi et al. (1991) did not find any significant correlations of IVE Impulsivity or Ven- turesomeness with subjective responses to alcohol, although both scales were predictive of lessened psychomotor impairment after alcohol dosing in men. In support of the theory that impulsivity reflects suboptimal cortical arousal, this lessened motor impairment was found to be a mediator in men of the significant correlations between impulsivity, alcohol use, and alcohol problems.

Although, due to our study design, it is impossible to say if the association of impulsivity with the intensity of cocaine-induced subjective effects was due to the reinforcing or discriminative stimulus functions of the stimulus compound (e.g., cocaine), our results seem to agree with the previously noted literature about stimulants. They also seem to confirm the hypothesis that links impulsivity to increased levels of sensitivity to signals of reward (Gray, 1981). These findings represent a laboratory confirmation of previously reported data (Yates, Fulton, Gabel, & Brass, 1989) that showed an association of cocaine abuse with types of personality disorders including borderline, histrionic, narcissistic, and antisocial because all of them share high levels of impulsiveness.

Because our subjects had comparable histories of exposure to cocaine self- administration, we can only speculate that, with equal drug availability, impulsive subjects show more "addiction" to the reinforcing effects of cocaine. It has been proposed, after operant behavior studies with humans (Barrat, 1981; Gordon, 1979; van den Broek, Bradshaw, & Szabadi, 1987), that impulsive subjects show systemic differences in their performance on a temporal differentiation schedule of reinforcement. The schedule specifies that a response is only reinforced if it occurs at least t seconds after the previous response. The poorer response of the impulsive subjects reflects an inability to withhold responding for the 10 seconds required by the schedule. Despite an accurate perception on the passage of time, impulsive subjects might show heightened sensitivity to the "incentive" aspect of the reinforcer, or an inability to delay responding.

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Mischel (1958) pointed out that a characteristic feature o f the behavior of young children, which he regarded as "impulsive," is the inability to tolerate delay o f gratification. We might speculate that the impulsive subjects o f ou r study, as part of their personal history, have been exposed to contingencies of re in forcement in which the value of the re inforcer was such that it gave rise to an increase of choices which, in turn, might have genera ted a lack of self-control (Logue, 1988). T h e reinforcing effects of cocaine, he igh tened by the low level of arousal that characterizes impulsive subjects (H.J. Eysenck, 1983), may then have interacted with this learned tendency for a lack of delay o f r e in fo rcemen t in o rde r to p roduce cont inuous drug-seeking and drug- taking behaviors.

T h e negative correlations between cardiovascular measures (systolic and diastolic blood pressure), af ter 40-mg cocaine administrat ion, and the Impulsivity and Venturesomeness subscales of the IVE quest ionnaire , if they are not chance effects, are suggestive of the notion that impuls ivi ty-extravers ion might be associated with a low level of autonomic arousal and reactivity. Cont ra ry to Black- burn's (1979) results, which showed a positive correlat ion between cardiovascular measures and pr imary psychopathy and sensation-seeking dimensions, o u r findings add suppor t to previous reports of autonomic hypoarousal and under reac- tion among psychopaths (Hare, 1975). Fur the rmore , a recent study (King, Jones, Scheuer, Curtis, & Zarcone, 1990) has demons t ra ted a significant negative correlat ion between plasma cortisol, a measure o f "trait low arousal," and impulsivity in a popula t ion of polysubstance misusers.

In conclusion, this prel iminary repor t suggests the presence of an association between personality dimensions and cocaine-induced subjective and cardiovascular effects. Finally, they call for fu r the r laboratory studies that might shed light on the mechanisms relating personality to drug-seeking and drug- taking behaviors.

REFERENCES

American Psychiatric Association. (1980). Dzagnostic and statistical manztal of mental dtsorders (3rd ed.). Washington, DC: Author.

Anderson, K.J., & Revelle, W. (1982). Impulsivity, caffeine, and proofreading: A test of the Eastbrook hypothesis. Journal of Experimental Psychology: Human Perception and Performance, 8, 614-624.

Barrat, E.S. (1981). Time perception, cortical evoked potentials and impulsiveness among three groups of adolescents. In E. Roberts, R. Hays, & L. Soloway (Eds.), Vwlence and vtolent tndiwdu- a/s. New York: Spectrum.

Blackburn, R. (1979). Cortical and autonomic arousal in primary and secondary psychopaths. Psycho- physiology, 16, 143-150.

Buss, A.H., & Durkee, A. (1957). An inventory for assessing different kinds of hostility. Journal of Consulting Psychology, 21, 343-349.

Chait, L.D., Uhlenhuth, E.H., & Johanson, C.E. (1989). Individual differences in the discriminative stimulus effects of d-amphetamine in humans. Drug Development Research, 16, 451-460.

Cregler, L.L., & Mark, H. (1986). Medical complications of cocaine abuse. New England Journal of Medicine, 315, 1495-1500.

Derogatis, L.R. (1975). The SCL-90-R. Baltimore, MD: Clinical Psychometrics Research. de Wit, H., Pierri, J., &Johanson, C.E. (1989). Assessing individual differences in ethanol preference

using a cumulative dosing procedure. Psychopharmacology, 98, 113-119.


de Wit, H., Uhlenhuth, E.H., & Johanson, C.E. (1986). Individual differences in the reinforcing and subjective effects of amphetamine and diazepam. Drug and Alcohol Dependence, 16, 341- 360.

de Wit, H., Uhlenhuth, E.H., Pierri, J., & Johanson, C.E. (1987). Individual differences in behavioral and subjective responses to alcohol. Alcohohsm: Clinical and Experimental Research, 11, 52-59.

Eysenck, H.J. (1983). Drugs as research tools in psychology: Experiments with drugs in personality research. Neuropsychobwlo~,, 10, 29-43.

Eysenck, M.W., & Folkard, S. (1980). Personality, time of day, and caffeine: Some theoretical and conceptual problems. Journal of P3ychology, 109, 32-41.

Eysenck, S.B.G., & Eyseqck, H.J. (1978). Impulsiveness and venturesomeness: Their position in a dimensional system of personality description. Psychological Reports, 43, 1247-1255.

Eysenck, S.B.G., Pearson, P.R., Easting, G., & Allsopp, J.F. (1985). Age norms for impulsiveness, venturesomeness and empathy in adults. Personahty and Indwtdual Differences, 6, 613-619.

Garau, A., & Garcia-Sevilla, L. (1986). Personality in rats and pain measures. Personality and Individual Difference~, 7, 567-569.

Garcia Sevilla, L. (1984). Extraversion and neuroticism in rats. Personahty and Individual D~fferences, 5, 511-532.

Gordon, M. (1979). The assessment of impulsivity and mediating behaviors in hyperactive and nonhyperactive boys. Jourmd of Abnormal and Chtld Psychology, 7, 317-326.

Gray, J.A. (1981). A critique of Eysenck's theory of personality. In H.J. Eysenck (Ed.), A model for personahty. New York: Springer.

Gupta, B.S., & Gupta, U. (1984). Dextroamphetamine and individual susceptibility to reinforcement in verbal operant conditioning. BTTtishJournal of Psychology, 75, 201-206.

Gupta, U. (1984). Phenobarbitone and the relationship between extraversion and reinforcement in verbal operant conditioning. Br~ti~h Journal of Psychology, 75, 499-506.

Haertzen, C.A., & Hooks, N.T.,Jr. (1969). Changes in personality and subjective experience associated with the chronic administration and withdrawal of opiates. Journal of Mental and Nervous Dtsea6es, 148, 606-614.

Hare, R.D. (1975). Psychopathy. In P.H. Venables & M.J. Christie (Eds.), Research in psychophysiology. New York: Wiley.

Hare, R.D. (1983). Diagnosis of antisocial personality disorder in two prison populations. Amelqcan Journal of P~ychiatry, 140, 877-890.

King, R.J., Jones, J., Scheuer, J.W., Curtis, D., & Zarcone, V.P. (1990). Plasma cortisol correlates of impulsivity and substance abuse. Personality and Individual Differences, 11, 287-291.

Kozel, N.J., & Adams, E.H. (1986). The epidemiology of drug abuse: An overview. Science, 234, 970-974.

Kumor, K.M., Sherer, M.A., & Cascella, N.G. (1989). Cocaine use in man: Subjective effects, physi- ologic response and toxicity. In G. Barnett (Ed.), Cocaine, marijuana, designer drugs: Chemistry, pharmacology and behavior. Cleveland, OH: CRC Press.

Kumor, K.M., Sherer, M.A., Gomez, J., Cone, E., & Jaffe, J.H. (1989). Subjective responses to intravenous infusion of cocaine. Pharmacology Biochemistrv aTut Behavior, 33, 443-452.

Kumor, K.M., Sherer, M.A., & Jaffe, J.H. (1989). Effects of bromocriptine pretreatment on subjective and physiological responses to i.v. cocaine. Pharmacology Biochemistry and Behavior, 33, 829-837.

Logue, A.W. (1988). Research on self-control: An integrating framework. Behavioral and Brain Sci- ences, 11,665-709.

London, E.D., Cascella, N.G., Wong, D.F., Phillips, R.L., Dannals, R.F., Links, J.M., Herning, R., Grayson, R., Jaffe, J.H., & Wagner, H.N., Jr. (1990). Cocaine-induced reduction of glucose utilization in the human brain. Archtves of General Psychiatry, 47, 567-573.

Mischel, F.A. (1958). Preference of delayed reinforcement: An experimental study of cultural obser- vation. JourTml of Abnormal and Social Psvchology, 56, 57-61.

Muntaner, C., Cascella, N.G., Kumor, K.M., Nagoshi, C., Herning, R., & Jaffe, J. (1989). Placebo responses to cocaine administration in humans: Effects of prior administration and verbal instruction. Psychopharmacology, 99, 282-286.

Muntaner, C., Kumor, K.M., Nagoshi, C., & Jaffe, J.H. (1989). Intravenous cocaine infusions in


humans: Dose responsivity and correlations of cardiovascular vs. subjective effects. Phalwmcol- ogy Biochemistry and Behavzor, 34, 697-703.

Muntaner, C., Kumor, K.M., Nagoshi, C., & Jaffe J.H. (1991). Effects of nifedipine pretreatment on subjective and cardiovascular responses to intravenous cocaine in humans. Psychopharmacology, 105, 37-41.

Muntaner, C., Walter, D., Nagoshi, C., Fishbein, D., Haertzen, C.A., & Jaffe, J.H. (1990). Self-report vs. laboratory measures of aggression as predictors of substance abuse. Drug and Alcohol Dependence, 25, 1-1 I.

Nagoshi, C., Kumor, K.M., & Muntaner, C. (1992). Test-retest stability of cardiovascular and subjective responses to intravenous cocaine in humans. British Journal of Addiction, 87, 591-599.

Nagoshi, C.T., Wilson, J.R., & Rodriguez, L.A. (1991). Impulsivity, sensation seeking and behavioral and emotional responses to alcohol. Alcoholism: Clinical and Experimental Research, 15, 661-667.

Robins, L.N., Helzer, J.E., Croughan, T., Williams, T.B.W., & Spitzer, R.L. (1981). Tile NIMH Diag- nostic Interv,ew Schedule: Verszon IIl [DHHS Publication No. ADM-T-42-3 (5-81, 8-81)]. Wash- ington, DC: U.S. Government Printing Office.

Schuster, C.R., Fischman, M.W., & Johanson, C.E. (1981). Internal stimulus control and subjective effects of drugs. In T. Thompson & C.E. Johanson (Eds.), Behavioral pharmacology of hunmn drug dependence (NIDA Research Monograph No. 37; DHHS Publication No. ADM 81-137). Washington, DC: U.S. Government Printing Office.

Sherer, M.A. (1988). Intravenous cocaine: Psychiatric effects, biological mechanisms. Biological P.LV- chiatry, 24, 865-885.

Sherer, M.A., Kumor, K.M., Mahaffey, J., Cone, E.J., & Jaffe,J.H. (1988). Suspiciousness induced by four-hour intravenous infusion of cocaine. Archwes of General Psychiatry, 45, 673-677.

Shipley, E. (1940). Shipley-Har{ford Retreat Scale: Manual. Hartford, CT: Neuropsychiatric Institute. Spear, D.J., Muntaner, C., Goldberg, S.R., & Katz, J.L. (1991). Methohexital and cocaine self-

administration under fixed-ratio and second-order schedules. Pharmacology Biochemistry and Behavior, 38, 411-416.

van den Broek, M.D., Bradshaw, C.M., & Szabadi, E. (1987). Behavior of "impulsive" and "non- impulsive" humans in a temporal differentiation schedule of reinforcement. Personality and Individual Differences, 8, 233-239.

Walter, D., Nagoshi, C., Muntaner, C., & Haertzen, C.A. (1990). The prediction of drug dependence from expectancy for hostility while intoxicated. Interuatioual Journal of the Addictions, 25, 1151-1168.

Yates, W.R., Fulton, A.I., Gabel, J.M., & Brass, C.T. (1989). Personality risk factors for cocaine abuse. American Journal of Public Health, 79, 891-892.

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Impulsiveness and subjective effects of intravenous cocaine administration in the laboratory