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National Institute on Drug Abuse
Women and Sex/Gender Differences Research
Director's Report to Council
Research Findings Excerpts
May, 1995
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Basic Research |
Effects of Prenatal Morphine Exposure
Dr. Vathy and her associates have reported recently that prenatal morphine exposure produces long-lasting, sexually dimorphic alterations in norepinephrine (NE) content and turnover rate in specific brain regions. This may indicate altered firing of NE cell bodies of origin or modification in local mechanisms regulating NE utilization at the level of terminals. Morphine also induced postsynaptic alterations in the brains of female rat offspring as mu opioid receptor binding was reduced in females but not in males. Like morphine, prenatal cocaine exposure in modest doses also produced long-lasting, sexually dimorphic alterations in adult sexual behavior and brain catecholamines in rat offspring; however, the alterations in the magnitude of behavioral changes were different than after morphine exposure. (Vathy et al., Dev. Brain Res. 73:1115-1122, 1993; Vathy et al., Brain Res. in press, 1995; Rimanoczy and Vathy, Society for Neurosci. 20:504A, 1994).
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Clinical Research |
Identification of Subtypes of Antisocial Personality Disorder
In a study focused on high risk behaviors, comorbidity and drug use conducted by Dr. Linda B. Cottler and her colleagues, new subtypes of Antisocial Personality Disorder (ASPD) were identified among 405 adult drug users admitted to treatment. To meet criteria for ASPD, a person must have exhibited irresponsible, socially non-conforming behaviors as an adult as well as a pattern of childhood conduct disorder (CD). Results of the study showed that a substantial proportion of injecting drug users met criteria for Adult Antisocial Behavior (AAB) without the childhood trajectory of CD. Using the Diagnostic Interview Schedule, a fully diagnosed ASPD group (with history of CD) was distinguishable from an AAB-only group (without history of CD). The findings identify a distinct subtype of ASPD, especially among women, and suggest a modification in the concept of ASPD.
Acute Thermogenic Effects of Nicotine Combined with Caffeine During Light Physical Activity in Male and Female Smokers
Perkins et al. (1994) studied the thermogenic effects of nicotine (15 ug/kg) and caffeine (5 mg/kg) alone or in combination, during physical activity (low intensity cycle ergometer riding) compared with rest in male and female smokers (n=10 each). The energy expenditure was measured by indirect calorimetry while subjects engaged low intensity cycle ergometer riding (activity) or were in quiet rest. There were significant thermogenic effects of nicotine and caffeine individually, while the combination of both produced additive effects. The energy expenditure attributable to nicotine, caffeine, or the combination significantly increased during activity compared with rest, but only in males. These differences in energy expenditure were not explained by the increased plasma levels of nicotine and caffeine during activity. The gender differences in the thermogenic effects of nicotine and caffeine during casual physical activity explained some of the apparent individual variability in expenditure due to tobacco smoking. In addition, eating played a more substantial role in the influence of nicotine on body weight in women than in men (Perkins KA, Sexton JE, Epstein LH, DiMarco A, Fonte C, Stiller RL, Scierka A, and Jacob RG. American Journal Clinical Nutrition, 60: 312-319, 1994).
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AIDS Research |
HIV Infection in Women with Injection Drug Using Partners
Dr. Stephanie Tortu and colleagues at the National Development and Research Institute examined the risk of HIV infection among a national sample of 5,162 heterosexual women with IDU partners recruited through street outreach and local networks of drug users. Three groups of women were distinguished and compared: those that had single sex partners, those with multiple partners, and those with multiple partners who also exchanged sex for drugs and/or money. Women with multiple partners who exchanged sex for drugs and/or money were at the highest risk for HIV, even when demographic variables were controlled. Tortu, S., Beardsley, M., Deren, S., and Davis, W. The Risk of HIV Infection in a National Sample of Women with Injection Drug-Using Partners. Am J Public Health. 84:1243-1249, 1994.
Women at High Risk for HIV
Dr. Sherry Deren and colleagues in the AIDS Research Consortium evaluated data on behavioral change among women IDUs and sexual partners of IDUs relative to pregnancy. Baseline and follow-up data were analyzed from a national sample of women who were pregnant at baseline, became pregnant between baseline and follow-up, or who were not pregnant at all during the study. Both pregnant and not pregnant high risk women reported significant levels of risk reductions at follow-up. IDUs who were pregnant or became pregnant reported greater reductions in drug injection rates, were more likely to report entering drug treatment, and reported the greatest reduction in sex risks compared to IDUs who remained non-pregnant. The findings indicate that the period of pregnancy provides an opportunity for changes in risk behaviors of women. Deren, S., Davis, W., Tortu, S., Beardsley, M., Ahluwalia, I., and the National AIDS Research Consortium. Women at High Risk for HIV: Pregnancy and Risk Behaviors. Journal of Drug Issues. 25(1):57-71, 1995.
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Epidemiology Research |
Co-morbidity and Co-transmission of Alcoholism, Anxiety, and Depression
Familial transmission analyses confirm findings regarding the specificity of transmission of alcohol and anxiety disorders. Relatives of probands with substance abuse/dependence showed increased rates of drug abuse/dependence and alcohol dependence (not alcohol abuse) compared to relatives of probands with alcohol abuse/dependence, anxiety disorders or normal controls. Specificity of transmission of drug abuse and alcohol abuse and specificity within specific drug classes also occurred. Results suggest that relatives of probands with substance abuse have more than a 2-fold increased risk of developing a substance abuse problem themselves. The rate of disruptive disorders was significantly elevated in offspring (age 7-18) of fathers with diagnoses of both substance abuse and antisocial personality disorder (44.4%) compared to offspring of fathers with anxiety or affective diagnoses (19.2%), both higher than rates of offspring of substance abusers without antisocial personality disorder (9.1%) and normals (7.1%). Analysis of subset of children (age 11-18) indicates that more than 27% of children of fathers with both antisocial personality disorder and substance abuse met diagnostic criteria for substance abuse or dependence whereas the risk for substance abuse was highest for offspring of mothers with a substance abuse diagnosis (30.8%), a 2-fold increase over offspring of mothers with anxiety or affective disorders and a 10 fold increase over offspring of normals. (Merikangas, KR, Risch, NJ, and Weissman, MM. Comorbidity and Co-transmission of Alcoholism, Anxiety and Depression. Psychological Medicine 24:69-80, 1994).
Gender-Differential Related Treatment Needs of the Homeless
The historical status of the homeless as being primarily older white men with alcohol problems is changing as the proportion of women in this population increases. In a 19-site Los Angeles County study comparing homeless men (n=386) and women (n=145), researchers found that homeless men, compared to homeless women, reported more substance use, longer periods of homelessness, poorer housing quality when not literally homeless, and greater criminal involvement. Homeless women were more likely than homeless men to have children living with them. Homeless men, compared to homeless women, showed stronger relationships between mental illness and prior institutionalization, between mental illness and drug use, between drug use and victimization. Homeless women, on the other hand, showed stronger relationships between drug use and alcohol use and between criminal involvement and drug use than did homeless men. Among all the homeless, men were more likely to use drugs and alcohol than were women, but among the homeless who are substance abusers, women were more likely than men to use multiple substances. These results underscore the differences in substance abuse treatment needs between homeless men and women. Stein, J. and Gelberg, L. Homeless Men and Women: Differential Associations Among Substance Abuse, Psychosocial Factors, and Severity of Homelessness. Experimental and Clinical Psychopharmacology, 3(1): 75-86, 1995.
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Etiology Research |
Gender Differences in the Pattern and Progression of Substance Use in Conduct Disordered Adolescents
Conduct disordered adolescents tend to initiate drug use earlier than other adolescents, and, among those with conduct disorder, females are more likely to have experimented with nonprescription diet pills and caffeine while males are more likely to have experimented with snuff or chewing tobacco. Women are at greater risk for qualifying for a diagnosis of nicotine dependence than were men. Although women start drinking alcohol at a later age than men, the latency from initial alcohol use to diagnosis of alcohol abuse/dependence is shorter for women than men, and the age at which males and females qualify for a diagnosis of alcohol abuse/dependence does not differ. Compared to the men, women also show a shorter latency from cannabis use to diagnosis of cannabis abuse/dependence. These findings are based on a sample of 40 female and 42 male adolescents qualifying for a conjoint diagnosis of conduct disorder and substance abuse disorder. The findings suggest that although the prevalence of substance abuse is higher in men, the liability to develop a supra-threshold disorder is greater in women when they do initiate drug use. Mezzich, A., Moss, H., Tarter, R., Wolfenstein, M., Hsieh, Y-C., and Mauss, R. Gender Differences in the Pattern and Progression of Substance Use in Conduct-Distorted Adolescents. The American Journal of Addictions, 3: 289-295, 1994.
Stability in Adolescent Friendship Group Context Across the School Year
The initiation and use of alcohol and cigarettes among adolescents is, to some extent, dependent on membership in friendship groups. Urberg and colleagues investigated the extent to which adolescents are in similar friendship group contexts in the Fall and Spring of a school year, and whether or not they are a member of the same friendship group. Gender and grade differences in the tendency to remain in the similar context were examined. Correlations across a range of variables between Fall and Spring were calculated separately for individuals who changed groups and for those who remained in the stable groups. For all but academic values, there was significant similarity in the group context from Fall to Spring, for both those who changed groups and those who remained in stable groups. The researchers conclude that adolescents who change peer groups do not dramatically change their peer context and that peer context is more stable for those who remain in the same group compared to those who change groups. Urberg, K., Rao, P., Mack, F., Stability in Adolescent Friendship Group Context Across the School Year. Paper presented at the Meeting of the Society for Research in Child Development, Indianapolis, March 1995.
Structure of Adolescent Peer Networks
In order to study the effects of peers on any aspect of adolescent development, but particularly on the initiation of drug use, the most comprehensive data to date on the structure of school-based peer networks has been collected by Urberga nd colleagues from Wayne State University. Their database consists of 90% or more of the population of three school systems with each subject naming up to 10 friends. Because subjects are matched to friends, mutuality could be assessed, and data from multiple sources could be used to assess friendship groups. The most robust finding was that females are more integrated into school social networks than males and that numeric minorities usually are less connected to school peer networks than the majority group. Of interest, few group effects replicated across the three schools. This strongly suggests that in order for programs to be maximally effective, attention must be given to school and community level differences that may substantially impact the organization of peer networks. Urberg, K., Degirmencioglu, S., Tolson J., Halliday-Scher, K., The Structure of Adolescent Peer Networks. Developmental Psychology, in press, 1995.
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Prevention Research |
Coaches' Perceptions About Patterns of Drug Use Among Their Teams
Women's sport teams provide a strong peer group and influential coaches to deter drug use and channel students' athletic goals into healthy behaviors. To investigate coaches' perceptions about patterns of drug use among their teams, Drs. Elliot, Wolf and Goldberg surveyed women coaches from Oregon high schools. Regardless of sport, they each estimated their team's prevalence of drug use as follows: Alcohol (25%), cigarettes (4%), anabolic steroids AS (0.1%), other teams' use AS (1.9%), women pro athletes use AS (11-20%), and eating disorders (5-10%). However, although the coaches felt they knew about nutrition and strength training, they demonstrated significant knowledge deficits in both areas. Despite overestimating their knowledge and underestimating prevalence of drug use and eating disorders, coaches strongly agreed with the need for coaching staff and team programs about ergogenic drugs, eating disorders, nutrition and strength training. Elliot, D., Goldberg, L., Moe, E. Health promotion/drug prevention for young women athletes: coaches' assessments of needs and behavioral norms. Medicine and Science in Sports and Exercise, 27(5), 1995.
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