Roy W. Pickens

Sex and Age Effects on the Inheritance of Alcohol Problems: A Twin Study

Male monozygotic cotwins of probands with Alcohol Abuse-Dependence (n = 85) were more likely than male same-sex dizygotic cotwins (n = 96) to report alcohol, drug, and conduct disorder problems. For women, rates of problem behavior did not differ between monozygotic (n = 44) and same-sex dizygotic (n = 43) cotwins. Opposite-sex dizygotic twin data (n = 88) revealed significant cross-sex transmission; alcohol problems were greatest among male cotwins of female probands. For men, proportion of liability variance associated with additive genetic factors was significantly greater when proband had an early (h2 = .73 +/- .18) rather than late (h2 = .30 +/- .26) age of onset. For women, heritability did not vary as a function of probands age of onset, and the pooled estimate suggested little genetic influence (h2 = .00, SE not computable). Findings suggest that genetic influences may be substantial only in the etiology of early-onset male alcoholism.

Self-administration of d-amphetamine by rats

SummarySelf-administration of d-amphetamine by rats was characterized by periods of drug intake and abstinence. Frequency of responding for drug injection was found to vary inversely as a function of drug dose per infusion (magnitude of reinforcement), and directly as a function of number of responses required per infusion (fixed-ratio reinforcement schedule). In several regards, reinforcement by d-amphetamine resembled that produced by electrical stimulation of the brain.

Genetic and environmental influences on drug use and abuse/dependence in male and female twins

Twins were recruited through alcohol and drug treatment programs. With structural equation modeling, genetic and environmental estimates were obtained for use and DSM-III abuse/dependence of sedatives, opioids, cocaine, stimulants, and cannabis as well as any illicit drug. Analyses were conducted separately for males and females. Models included thresholds based on population prevalence of use or abuse/dependence and ever having been in treatment. Genetic influences were found for most measures. They were generally stronger for males than females and for clinical diagnoses of abuse/dependence compared to use. Common environmental influences played a greater role in use than abuse/dependence.

Tobacco withdrawal. symptoms: An experimental analysis

This study was a prospective examination of tobacco withdrawal symptoms in a controlled environment. Smokers (N=27) were hospitalized for a 7-day period during which a battery of tests was administered. Smokers were assigned to either an experimental group (N=20) or a control group (N=7). Subjects in the experimental group smoked ad libitum for a 3-day baseline period and then underwent 4 days of tobacco deprivation. Subjects in the control group continued to smoke ad libitum throughout the study. Of the 37 measures of tobacco withdrawal employed in this study, nine showed significant changes following tobacco deprivation. These changes include decreased heart rate and increased caloric intake, weight, craving for tobacco, confusion, depression-dejection, number of awakenings, duration of awakenings, and increased poor concentrations as observed by others.

Drug level of d- and l-amphetamine during intravenous self-administration

Rats were allowed to self-administer dextro and levo isomers of amphetamine in doses of 0.25, 0.50, 0.75 and 1.0 mg/kg/injection for 6 h/day. Total body level of drug was calculated at the time of responding for each drug injection. Body level of amphetamine initially increased and then decreased (0–2 h), and thereafter remained relatively constant for the remainder of the experimental session (2–6 h). During 2–6 h of self-administration, calculated whole body levels of both d- and l-amphetamine remained relatively constant across injection doses. In another study, blood was removed several times during 2–6 h at the time of responding for drug injection. Again, no difference in blood level of 14C-amphetamine was found across a range of injection doses. Mean blood levels were 0.48 Μg/ml for l-amphetamine and 0.18 Μg/ml for d-amphetamine. Drug intake averaged 2.0 mg/kg/h for l-amphetamine and 0.79 mg/kg/h for d-amphetamine.

Craving: consensus of status and agenda for future research ☆

The term craving is used frequently in relationship to drug abuse and its treatment but there is disagreement over its definition and role. In February 1991, a meeting of experts from several disciplines, sponsored by the Addiction Research Center (ARC) of the National Institute on Drug Abuse, was convened with the goal of reaching consensus about the importance of craving and to suggest a future research program. The participants agreed that craving is a subjective state in humans that is associated with drug dependence but little is known about its determinants, relationship to drug taking, and measurement. To advance our knowledge, a substantial research program is required. The outcome of this research effort could have important consequences for increasing our understanding of the determinants of drug abuse.

Common genetic mechanisms in alcohol, drug, and mental disorder comorbidity

Comorbid drug and mental disorders were assessed in 63 monozygotic (MZ) and 67 dizygotic (DZ) twin pairs. DSM-III alcohol dependence was heritable in males when probands had a comorbid DSM-III drug or mental disorder but not when probands had only alcohol dependence. For males, significantly higher cross-MZ than cross-DZ correlations were found between alcohol dependence in probands and certain mental and drug disorders in cotwins. In contrast, females showed higher within-twin than cross-MZ correlations and similar cross-MZ and cross-DZ correlations between alcohol dependence and all mental and drug disorders. These results suggest comorbidity between alcohol and certain drug and mental disorders in males in epidemiological surveys may be due in part to genetic influences.

COST-EFFECTIVENESS OF TREATMENT FOR DRUG-ABUSING PREGNANT WOMEN

Neonatal intensive care unit (NICU) and drug treatment costs were compared in two groups of pregnant drug abusing women: 100 admissions to a multidisciplinary treatment program and active in care at the time of delivery and 46 controls not entering drug treatment. Clinical measures included urine toxicology at delivery, infant birthweight. Apgar scores and need for and duration of NICU services. Cost measures included drug treatment and NICU costs. Treatment patients showed better clinical outcome at delivery, with less drug use and higher infant estimated gestational age, birthweight and Apgar scores. Infants of treatment patients were also less likely to require NICU services and, for those that did, had a shorter stay. When total cost was examined (including drug treatment), mean net savings for treatment subjects was

Chemical Interactions in Methamphetamine Reinforcement

4644 per mother/infant pair. The study demonstrates the cost-effectiveness of treatment for pregnant drug abusing women, with savings in NICU costs exceeding costs of drug treatment.

The relationship between chronic ethanol exposure and cigarette smoking in the laboratory and the natural environment

Responding by rats was reinforced by intravenous infusions of 0.5 mg/kg methamphetamine hydrochloride. The effects of intraperitoneal injections of various doses of methamphetamine, alpha-methyl-para-tyrosine (AMPT) and 3, 4-dihydroxyphenylalanine (1-DOPA) were determined on this baseline. Intraperitoneally-administered methamphetamine produced a dose-related pause in responding, apparently indicating drug satiation. Injections of AMPT caused responding either to increase at low doses, or, at intermediate and high doses, to increase, then cease altogether, and finally return at a high rate which decreases to baseline. Injections of 1-DOPA had no noticeable effect on drug responding. Some biochemical implications of these data were discussed.