 |
National Institute on Drug Abuse
Women and Sex/Gender Differences Research
Director's Report to Council
Research Findings Excerpts
September, 1995
|
 |
Basic Research |
Marijuana and Pregnancy
NIDA supported researchers, Dr. S.K. Dey and his associates from the University of Kansas Medical Center, Kansas City, recently reported that both brain- and spleen-type cannabinoid receptor mRNAs are expressed in the preimplantation mouse embryo; whereas in the mouse uterus, only the brain-type cannabinoid receptor mRNA is expressed. They also observed that both oviduct and uterus had the capacity to synthesize the putative endogenous cannabinoid ligand, anandamide, suggesting the preimplantation mouse embryo and the uterus as targets for cannabinoid ligand-receptor signaling. Although the significance of these findings especially in the preimplantation mouse embryo with the cannabinoid binding sites several fold higher than those in the brain needs to be determined, these findings are still important from the public health view/concern. From these results, the P.I. suggests that the reported adverse effects of cannabinoid use or abuse seen during pregnancy and in uterine disorders could be due to an aberrant expression of the endogenous ligand in the reproductive tract and of the receptors in the embryo and uterus. (S.K. Das, B.C. Paria, I. Chakraborty and S.K. Dey, Proc. Natl. Acad. Sci. 92: 4332-4336, 1995; B.C. Paria, S.K. Das and S.K. Dey, Proc. Natl. Acad. Sci., in press.)
Gender Differences in Responses to Acute Cocaine
Gender differences after acute cocaine administration have received little attention despite the fact that males and females respond differently to many other drugs. Dr. Scott Lukas and colleagues of McLean Hospital and Harvard Medical School have recently reported (in press) the results of a study examining seven male and seven female occasional cocaine users who received either an intranasal dose of cocaine hydrochloride (0.9 mg/kg) or placebo powder. Women studied during the follicular and luteal phase of their menstrual cycle had peak plasma cocaine levels of 77.5"13.6 ng/ml and 61.3"17.5 ng/ml, respectively. Male subjects achieved the highest peak plasma cocaine levels (144.4" 17.5 ng/ml), detected cocaine effects significantly faster than females and also experienced a greater number of episodes of intense good effects or "euphoria." Cocaine-induced tachycardia paralleled the subjective effects and plasma levels. Peak increases in heart rate occurred more rapidly in males. These data suggest that there are significant gender differences in the responses to acute intranasal cocaine.
|
Clinical Research |
Physiological and Subjective Responses to Food Cues as a Function of Smoking Abstinence and Dietary Restraint
Tobacco smokers gain weight after quitting smoking with women usually gaining more weight than men. This weight gain after quitting smoking appears to be from increased eating, especially of sweet-tasting between-meal snacks. The investigators examined the influence of smoking abstinence on physiological (salivary habituation) and subjective (cigarette desire, hunger, taste liking, emotional arousal) responses to food cues in women smokers, 10 each in high or low dietary restraint groups, respectively. Dietary restraint is associated with chronic concerns about weight and dieting to attempt to maintain an unreasonably low body weight and is measured by the Revised Restraint Scale of Herman and Polivy. The subjects were divided into two groups: those who scored >15 (high restraint) and low restrainers who scored <15 on the scale. The salivary responses to taste increased significantly more in high vs. low restraint women smokers during the first trial of taste, especially on the smoking day. However, the salivary habituation to strawberry yogurt was significantly disrupted by smoking abstinence in high restraint women. High restraint women also reported increasing desire for cigarettes and emotional arousal across food taste trials on both days, while the low restraint women reported no changes over trials. Results indicate that brief smoking abstinence attenuates salivary habituation to taste in high restraint women, suggesting a marker for processes responsible for increased food intake after quitting smoking. Repeated exposure to food stimuli may also increase emotional distress in high restraint women smokers, enhancing desire to smoke (Perkins KA, Mitchell SL, Epstein LH, Physiol Behav 58(3):000-000, 1995).
Individual Variability in Responses to Nicotine
Individual variability in acute responses to nicotine is generally attributed to stable characteristics of tobacco users such as genetic/constitutional factors (e.g., gender) and chronic environmental experience (behavioral factors). Perkins et al. show that the situational factors such as acute stress or physical activity may also play an important role in variability to nicotine effects. The situational influences may determine why smokers are more likely to smoke under certain conditions, such as high stress. Females may be more responsive than males to non-nicotine stimuli associated with smoking (e.g., sight and taste of smoke). The effects of many psychoactive drugs (including nicotine) on behavior may be strongly determined by the situational context surrounding drug intake (e.g., accompanying environmental and social stimuli, temporal factors), and not simply the pharmacology of the drug. The pre-drug subjective state, ongoing level of physical activity vs. rest, and concurrent drug intake, all are situational factors that may result in individual variability in nicotine's subjective, behavioral, and physiological responses (Perkins, Behavior Genetics, 25(2): 119-132, 1995).
Gender Differences in Cerebral Perfusion in Cocaine Abuse: Technitium-99m-HMPAO SPECT Study of Drug-Abusing Women
Mendelson and his colleagues measured cerebral perfusion of 13 cocaine-dependent men (average age of 32.4+6.7 years) and 13 women (average age of 34.6+4.6 years), and an equal number of controls. The investigators found that cocaine dependent women had much less abnormal findings of cerebral perfusion (both in terms of number of defects/patient and the proportion of patients affected) than cocaine-dependent men and were indistinguishable from normal women. These gender differences could not be explained by age, race, body mass index, alcohol use, amount of cocaine use, amount of heroin use, the route of drug administration, or any other structural abnormality. The underlying mechanism of these gender differences remains to be established. The concurrent use of heroin and cocaine was associated with more perfusion abnormalities in both sexes, that has been reported also in animals (Levin JM, Holman LB, Mendelson JH, Teoh SK, Garda B, Johnson KA, Springer S, Journal of Nuclear Medicine, 35(12):1902-1909, 1994).
|
AIDS Research |
Not-in-treatment Male and Female IDUs and Crack Smokers
Sherry Deren and colleagues examined data from a national sample of not-in-treatment male and female IDUs and crack smokers to determine relative risks of HIV positive serostatus by sexual orientation. Data were collected on sexual orientation from 11,956 respondents in 16 cities participating in NIDA's Cooperative Agreement for AIDS Outreach/Intervention Research Program from 1990 to 1993. There were 8,423 men (70%), 47% of whom were IDUs, 31% crack smokers, and 21% both IDUs and crack smokers, and 3,533 women (30%), 37% of whom were IDUs, 44% crack smokers, and 18% both. Significant differences were found in drug use by sexual orientation for both males and females. Gay and bisexual males were more likely to be crack smokers and heterosexual males were more likely to be IDUs; gay and bisexual females were more likely to be both injectors and crack smokers. HIV positive serostatus among males was highest among gay men, followed by bisexuals; there was no significant difference in seropositivity within risk category by sexual orientation among females. The paper discusses the implications of relative HIV risks among not-in-treatment drug users by sexual orientation for improving targeted outreach and prevention interventions. Sexual Orientation and HIV Risk Behaviors in a National Sample of Injection Drug Users and Crack Smokers. Drugs and Society (in press).
Drug Use and AIDS Risk Behavior Among Homeless Women
A causal model consisting of personal and social resources, threat appraisal processes, coping styles, and barriers to risk reduction as predictors of general AIDS risk and specific drug use behaviors was investigated among homeless African American (N=714) and Latina (N=691) women aged 18 to 69 years (mean age 32). The model, which was based on a stress and coping framework, supported many of the hypothesized relationships. Active coping was associated with fewer general AIDS risk behaviors for both groups and less specific drug use behavior among African American women. Specific drug use behavior was predicted by high threat appraisal and more avoidant coping for both groups. Behavioral differences between the two ethnic groups were found, especially on the risky AIDS and drug use behavioral measures. Furthermore, less self-esteem predicted more barriers to condom use among the African American women whereas more social resources predicted more barriers among the Latinas. Thus, culture-specific strategies may be necessary to increase condom use among such high risk populations. Nyamathi A, Stein JA & Brecht M. Psychosocial Predictors of AIDS Risk Behavior and Drug Use Behavior in Homeless and Drug Addicted Women of Color. Health Psychology, 14:1995:265-273.
Barriers to Condom Use and Needle Cleaning Among Impoverished Minority Female IDUs and Their IDU Partners
Based on a study of women recruited primarily from homeless shelters and drug recovery programs, the most commonly cited barriers to condom use were belief that partners did not have acquired immunodeficiency syndrome (AIDS), lack of knowledge about where to get and how to use condoms, and discomfort discussing condom use with partners. African-American women were more likely to report having multiple partners and unprotected sex, and more likely to report barriers in using, discussing and obtaining condoms. Latina women were more likely to report partners' dislike of condoms. African- American and highly acculturated Latina women were more likely to be IDUs than less acculturated Latina women. The more pervasive barriers for needle cleaning were not having personal needles, being high and not interested in needle cleaning, and not having disinfectant available. In a multiple logistic regression analysis for engaging in unprotected sex and cleaning needles, no ethnic or acculturation differences were found after controlling for selected demographic characteristics and risk factors. The data indicate a need to increase the supply of free or low cost condoms, to provide easily accessible sites for obtaining condoms, and to focus counseling for women on negotiating condom use with partners and the skillful and correct placement of the condoms. Nyamathi, A., Lewis, C., Leake, B., Flaskerud, J., Bennett, C. Barriers to Condom Use and Needle Cleaning Among Impoverished Minority Female Injection Drug Users and Partners of Injection Drug Users. Public Health Reports, 110:1995:166-172.
|
Epidemiology, Etiology and Prevention Research |
Antecedents and Consequences of Drug Abuse
Predictors and outcomes of various types of drug use are examined in prospective data spanning four years in the lives of young adult men and women (N=547, 156 women). It was hypothesized that the causes and consequences of drug use are different for this stage of life (compared to childhood and adolescence) and would involve gender-role expectations that women are most directed toward communality issues, whereas men are concerned with agenetic tasks. It was also hypothesized that failure in these gender-specific tasks would lead to more future drug use and that earlier drug use would hinder the development of these skills for men and women. Analyses were conducted with structural equation models incorporating repeatedly-measured constructs of polydrug use, communality, and agency. Results generally supported these expectations when both specific and general effects were considered. In addition, women's drug use also interfered with their agenetic goals and men's drug use damaged their communal relationships. Newcomb, M.D., & Jack, L.E. Drug Use, Agency, and Communality: Causes and Consequences Among Adults. Psychology of Addictive Behaviors, 9:1995:67-82.
Female Gangs and Involvement of Women in Drug Distribution
Joan Moore and John Hagedorn who previously studied male gangs, conducted an ethnographic study of female gangs. As with the males, not all gang members are the same: Legits have left the gang and "hood" behind; Dope fiends are addicted to cocaine and need drug treatment; New jacks have given up on the legal economy and see no wrong in selling cocaine to anyone; Homeboys/Homegirls, the majority, work regular jobs but when they can't make enough money, sell cocaine which bothers them because they want to settle down and have a decent life. Gangs fall apart over selling drugs which is typically done by individuals who compete with one another. Among African American and Hispanic gangs, sales are more to Whites, outsiders, and middle class customers; markets are closed to rival gangs and as profits increase, gangs tend to become more organized. Latinos tend to stay involved with their gang as adults while adult African Americans tend to be less involved with their gang. Moore, J. & Hagedorn, J. Gangs in America, R. Huff, (ed.), 1995.
Prevention Interventions for Tobacco Use
The development of interventions for the prevention of tobacco use is an ongoing concern, particularly in minority communities. Examination was made of the prevalence and sociodemographic predictors of having a cigarette brand preference in African-American, Mexican-American, and White primary and secondary school students. Cross-sectional data were used from a school based survey of drug use sequencing conducted in 1992 which included students from 47 schools. The prevalence of having a preferred brand of cigarette increased with grade level, with over 20% of 11th graders reporting a preference. White females and males, and Mexican-American males were more likely to have a preferred brand of cigarette than African-American females and males, and MexicanAmerican females. Brand preference was related to cigarette use in a dose response fashion for all subgroups, with African-American "regular" smokers most likely to report a preferred brand of cigarette. Cigarette brand preference was a strong risk factor for daily cigarette use. Volk, R.J., Edwards, D.W., Lewis, R., Schulenberg, J. Paper presented at Research Society on Alcoholism, June 1995.
The Role of Sexual Assault in Adolescent Pregnancy and Drug Use
In a longitudinal natural history of drug use among young women who become pregnant before reaching age 18 (N=241) 32% reported a history of early forced sexual intercourse (rape or incest) according to Dr. Lewayne Gilchrist and her colleagues at the University of Washington, Seattle. These adolescents compared with non-victims used more crack, cocaine, and other drugs (excepting marijuana), had lower self-esteem, and engaged in a higher number of delinquent activities. A discriminant function analysis incorporating a model of negative consequences of early forced intercourse (which included drug use variables) distinguished reported victims from non-victims 67% of the time. Roughly half the sample is non-white (28% African-American; 8% American Indian, 5% Latinas, 4% Asian; 4% mixed ethnicity). All arelow-income. They represent the population of young urban women who received at least minimal services from health and social service providers serving pregnant women and were not recruited on the basis of known drug use. Being pregnant, unmarried, under 18, and planning to parent their child were the inclusion criteria. Subjects average age was 16 (range=12 to 17). Self report and urine toxicology analyses were used to assess drug use. Less than 0.5% of self-report drug use had to be adjusted based on lab results. The principle question eliciting the intercourse data was "Have you ever been forced to have sex when you had no choice and had to do it?" Findings indicate that drug use among the teen pregnancy population may be part of a syndrome of effects associated with sexual abuse among girls. Rates for sexual abuse as well as for drug use before and after pregnancy in this school-age sample were high. Forced sex may be one of many aspects of a context of risk that affect drug initiation and maintenance of drug use among young women of child-bearing age. The effects of early forced intercourse are detectable in their women's psychological, behavioral, and social functioning several years after the original incident. (Lanz, J.B. Psychological, Behavioral, and Social Characteristics Associated with Early Forced Sexual Intercourse Among Pregnant Adolescents. Journal of Interpersonal Violence, 10(2):1995:188-200.)
Drug Use and the Severity of Homelessness
Latent variable multiple-group confirmatory factor analyses assessed gender differences in relations among drug and alcohol use, measures indicating severity of homelessness, criminal history, prior institutionalization, and mental illness (N=531 homeless persons, [145 women]; age 16-78; mean age 34 years). Severity was indicated by time homeless, housing quality, and victimization. Men reported more substance use, a longer time homeless, poorer housing quality, greater criminal involvement, and less likelihood of living with a child. Constrained multiple-group models surfaced five significantly different relationships between latent constructs. Men had stronger relationships between mental illness and prior institutionalization, drug use and mental illness, and drug use and victimization, whereas women had stronger relationships between drug use and alcohol use, and criminal involvement and drug use. Stein, J.A., & Gelberg L. Homeless Men and Women: Differential Associations Among Substance Abuse, Psychosocial Factors, and Severity of Homelessness. Experimental and Clinical Psychopharmacology, 3:1995:75-86.
Parental Influences on Early Adolescent Deviant Behavior
Having fewer than two supportive parents generally increases the risk of deviant behavior, but more so for boys than for girls. This is the conclusion of a longitudinal study of 601 families examining the separate and combined effects of parental psychiatric disorders, supportive parent-child communications, and household income on the development of deviant behavior in boys and girls 11 to 14 years of age. Deviance in this study was defined on the basis of 15 specific behavior patterns, including three related to substance use (began drinking or using drugs, smoked cigarettes during the past 30 days, and drank alcohol in the past 30 days). The relationships between having fewer than two supportive parents and deviant behavior was more pronounced when one or more parents had a chronic mental disorder (principally depression and substance abuse), but the combination of fewer than two supportive parents and one psychiatrically impaired parent had a particularly marked effect on girls. Moreover, older children's behavior is affected more dramatically by parental mental disorders, especially among girls; 13-to-14-year-old girls with both parental risk factors were virtually as deviant as male agemates with both risks. Each of these effects is present regardless of family income level, but without these risks, household income is negatively related to deviant behavior. Johnson, R.A., Su, S.S., Gerstein, D.R., Shin, H.C. & Hoffmann, J.P. Parental Influences on Deviant Behavior in Early Adolescence: A Logistic Response Analysis of Age- and Gender-Differentiated Effects. Journal of Quantitative Criminology, 11:1995:167-193.
Natural History of Crack Cocaine Users
Bruce Johnson and colleagues reported recent findings from their analysis of data from an eight year (1989-1997) natural history cohort study of crack cocaine dealers and users in New York City. They found that crack cocaine use has been on a steady decline since peaking in the mid to late 1980s and that crack dealing has shifted from conspicuous sales in open, outdoor drug markets to clandestine sales in private settings in apartments buildings. The decline in use of crack cocaine appears to reflect both changing attitudes and norms among youth as well as general shifts among drug users to powdered cocaine and smokable heroin. The authors report there has been a notable increase in the number of female crack cocaine sellers; they speculate that this may be because of the high incarceration rates of male crack cocaine dealers as well as the declining profitability from selling the drug. Golub, A., Johnson, B., and Fagan, J. Careers in Crack Use, Drug Distribution, and Nondrug Criminality. Crime and Delinquency; 41; 3; 1995; 275-295.
[Previous Report][Index][Next Report]
|
