National Institute on Drug Abuse
Director's Report to the National Advisory Council on Drug Abuse
February 1997
Research Findings
Epidemiology, Etiology and Prevention Research
Monitoring The Future Results from the 1996 Monitoring the Future
Study were released on December 19, 1996 (Lloyd Johnston, et al). Following
are the most significant findings:
Between 1995 and 1996 use of cigarettes and marijuana increased
notably among 8th and 10th graders. In addition, fewer of these students
expressed negative perceptions of marijuana use. For 8th and 10th grade
students, these changes replicate recent trends that began in the early
1990s. However, for seniors, this year's data indicate that the rate of
increase of use has slowed and that attitudes are improving somewhat, with
many differences in use and attitudes between 1995 and 1996 being non-statistically
significant. Unless noted otherwise, all changes presented below are statistically
significant.
Illicit Drug Use
- Use of marijuana/hashish continued to climb, especially among 8th
and 10th graders. Between 1995 and 1996, lifetime, past year, past month,
and daily marijuana use increased among 8th and 10th graders, while
only lifetime use increased among 12th graders. Since 1992 past year
marijuana use has increased in all three grades and in virtually all demographic
and geographic subdomains surveyed. (i.e., gender, census region, population
density, and race/ethnicity). The only exception was no change among Hispanic
Americans in 12th grade.
- Driven in large part by the rise in marijuana, lifetime, past year,
and past month use of any illicit drug increased among 8th and 10th graders.
- Past month use of hallucinogens decreased among 12th graders between
1995 and 1996, as did past month use of LSD among 10th and 12th graders.
- Lifetime use of cocaine in any form increased for 10th graders while
past year use increased for 12th graders. Use of crack for all recency periods
remain unchanged among all three grades.
- Lifetime, past year, and past month use of tranquilizers increased
for 8th graders while lifetime use increased for 10th graders.
- Heroin use did not change among seniors, 10th, and 8th graders.
- Use of stimulants for any recency period did not change among any
grades.
Perceived Harmfulness and Availability
- The percentage of 10th graders reporting "great risk" in
trying marijuana once or twice or in smoking the drug occasionally decreased.
Among 8th graders, the percent reporting "great risk" in regular
marijuana use decreased from 73.0 percent in 1995 to 70.9 percent in 1996.
The percent of seniors reporting "great risk" in regular marijuana
use decreased steadily from 78.6 percent in 1991 to 60.8 percent in 1995,
and remain unchanged at 59.9 percent in 1996.
- The perceived risk (percentage reporting "great risk") of
smoking a pack or more of cigarettes per day remain unchanged among all
three grades.
- The perceived risk of trying inhalants once or twice or using them
regularly, increased among 8th and 10th graders.
- The perceived risk of taking one or two drinks once or twice each
weekend deceased for 8th graders and increased for 12th graders. Also the
perceived risk of taking one or two drinks nearly every day decreased among
8th graders.
- The percentage reporting that marijuana was "fairly easy"
or "very easy" to get increased among 8th and 10th graders. The
perceived availability of amphetamines and steroids decreased among seniors.
Alcohol Use
- As in past years, alcohol continues to be used at unacceptably high
levels. Notably, however, daily drinking and "being drunk" during
the past month increased among 8th graders.
Cigarette Use
- Between 1995 and 1996, past month cigarette use increased from 19.1
to 21.0 percent among 8th graders and from 27.9 to 30.4 percent among 10th
graders. Daily smoking increased from 16.3 to 18.3 percent among 10th graders.
Among subgroups in 10th grade, increases occurred for males and females,
whites, and those with college plans.
- Since 1991, past month smoking has increased from 14.3 to 21.0 percent
for 8th graders, 20.8 to 30.4 percent for 10th graders, and 28.3 to 34.0
percent for 12th graders.
- From 1995 to 1996, smoking _ pack or more per day increased among
8th and 10th graders.
Cannabinoid Receptor Gene (CNR1): Association with IV Drug Use David
Comings at the City of Hope (Duarte, CA) and colleagues compared individuals
who were homozygous for 5 or more triplet repeats (of AAT) in the cannabinoid
receptor gene (CNR1) with individuals who were either heterozygous, or homozygous
for less than 5 repeats. The sample was selected from an inpatient Addiction
Treatment Unit (ATU) and hospital or university controls. While there was
no greater frequency of homozygous > 5 repeat genes in controls versus
ATU subjects, there was a significantly (nearly twice) greater number of
these homozygotes among subjects in the ATU who took drugs intravenously.
This difference prevailed regardless of the drug of choice: amphetamine,
cocaine, or heroin. Using a factor analysis to combine diagnostic questions,
the first two factors consisted of questions primarily associated with drug
dependence (Factor 1) or alcohol dependence (Factor 2). Those homozygous
for > 5 repeats had a significantly higher Factor 1 (drug dependency)
score than the other genotypes, but there was no difference between the
genotypes on the Factor 2 (alcohol dependence) score. Comings, D.E., Muhleman,
D., Gade, R., Johnson, J. P., Verde, R., Saucer, G, MacMurray, J. Cannabinoid
Receptor Gene (CNR1): Association with IV Drug Use, Molecular Psychiatry,
In Press. In a related study, male subjects of the ATU with the homozygous
> 5, > 5 genotype had significantly lower amplitudes of the P300 evoked
potential, especially in the frontal lobe leads compared to the heterozygote
(> 5, < 5) or < 5, <5 homozygote genotypes. Lowered P300 amplitudes
have been associated with subjects with substance dependence or their off-spring.
Johnson, J. P., Muhleman, D., MacMurray, J., Gade, R., Verde, R., Ask, M.,
Kelley, J., and Comings, D.E. Association between the Cannabinoid Receptor
Gene (CNR1) and the P300 Event-related Potential. Molecular Psychiatry,
In Press. The authors hypothesize that the varying lengths of the triplet
repeats affects gene regulation and that the magnitude of the effect is
dependent upon the length of the repeats. These studies report behavioral
outcomes (greater IV drug use and lowered P300 amplitudes) for homozygotes
with >5 repeats.
The Relationship Between Childhood Maltreatment and Delinquency This
study analyzed data from the Rochester Youth Development Study to investigate
the relationship between childhood maltreatment and later adolescent involvement
in delinquency. A significant relationship was found between child maltreatment
and later delinquency, even when controlling for other factors. It appears
that more extensive maltreatment was related to higher rates of delinquency.
The majority of maltreated youth however demonstrated resilience in terms
of serious delinquency. The findings point to further research needs on
which to base the design of interventions. Smith, C. and Thornberry, T.P.
The Relationship Between Childhood Maltreatment and Adolescent Involvement
in Delinquency. Criminology, 33(4), pp. 451-481, 1995.
Perception of Friends' Drug Use among Urban Schoolchildren Linked to
Own Prior Use Relations between adolescents' substance use and perceptions
of their friends' substance use were examined cross-sectionally and longitudinally
in a predominantly African American school district. Students in the 4th
and 5th grades were surveyed and tracked for 4 consecutive years. Cross-sectional
samples included 3,073, 5,955, 7,701 and 6,616 students in years 1 to 4
respectively. The longitudinal sample included 1,802 students surveyed every
year. Self-reported substance use of friends and classmates also was assessed.
Perceived friends' substance use had a stronger association with the child's
own prior substance use than with the friend's self reported substance use
in every year. Perceived family use and classmates' self reported use also
made independent contributions to regression models. Longitudinal structural
equation analyses indicated that perceived friends' use is more likely to
be a product of an adolescent's previous substance use than a precursor
of subsequent substance use. Findings contradict prevailing theories on
the influence of peers on substance use. Perceived use by peers instead
derived from one's own prior use. Iannotti, R.J., Bush, P.J., and Weinfurt,
K.P. Perception of Friends' Use of Alcohol, Cigarettes, and Marijuana among
Urban Schoolchildren: A Longitudinal Analysis. Addictive Behaviors, 21(5),
pp. 615-632, 1996.
Trends Among American Indian Youth Dr. Frederick Beauvais of Colorado
State University reported that Indian youth residing on reservations continue
to show very high rates of drug use compared to their non-Indian peers.
Although overall drug use has decreased from its high levels of the 1970's
and 1980's, heavy involvement with drugs is reported by about 20 percent
of Indian adolescents, a proportion that has not changed since 1980. These
findings are based on cross-sectional school survey data of 8th-12th grade
Indian youth covering the 20 years from 1975 through 1994. The school survey
is augmented by a special study of dropouts to permit adjustment of estimates
to represent the total population of Indian youth. The investigator concludes
that Indian youth, particularly dropouts, remain at high risk for drug use
and abuse. Similar trends for these youth and their non-Indian counterparts
suggest that prevention strategies effective with other youth can be effective
with Indian youth. Beauvais, F. Trends in Drug Use Among American Indian
Students and Dropouts, 1975-1994. American Journal of Public Health, 86(1),
pp. 1594-1598, Nov., 1996.
Determinants of Drug Abuse in Urban Black Youth This study examined
the role of cognitive efficacy, personal anomie, and general deviance in
predicting substance use in a sample of urban black youth. The study also
examined the reliability and construct validity of measurement of these
three factors in adolescents. The findings underscore the primacy of deviance
in predicting drug use for minority youth, and the need to incorporate affective
influences into current interventions strategies. Scheier, L.M. and Botvin,
G.J. Purpose of Life, Cognitive Efficacy, and General Deviance as Determinants
of Drug Abuse in Urban Black Youth. Journal of Child & Adolescent Substance
Abuse, 5(1), pp. 1-26, 1996.
Identifying High-Risk Youth: Prevalence and Patterns of Adolescent Drug
Abuse Newcomb (1995) reviewed the literature on drug abuse epidemiology
and etiology in regard to identifying youth at high risk. Data from both
national and local samples were presented indicating disturbing upward trends
in use of illicit drugs among teenagers. Numerous risk and protective factors
were delineated as reflecting four biopsychosocial domains including biogenetic,
intrapersonal, social, and socio-cultural influences. New analyses were
presented that incorporated multiple risk and protective factors into cumulative
indices and both the direct and moderating effects of these on drug use
and abuse were evaluated. Newcomb extended this etiological approach to
understanding drug use and abuse among ethnically-diverse teenagers. Both
similarities and differences in risk and protection exposure and impact
on drug use were emphasized. This information was discussed in regard to
common versus unique approaches to drug abuse prevention among adolescents
from ethnically-diverse backgrounds. In both chapters, drug use is characterized
as an important aspect or symptom of general deviance that cannot be studied,
predicted, or prevented in isolation from the fabric of other types of deviance.
Newcomb, M.D. Identifying High-Risk Youth: Prevalence and Patterns of Adolescent
Drug Abuse. In E. Rahdert and D. Czechowicz, (Eds.), Adolescent Drug Abuse:
Clinical Assessment and Therapeutic Interventions, pp. 7-38, 1995. National
Institute on Drug Abuse, Rockville, MD.
Alcohol Sensitivity and Smoking History in Men and Women Many studies
have found genetic effects to contribute to alcoholism risk in both men
and women. Based on preliminary evidence for shared genetic risk between
smoking and drinking problems, a re-analysis of alcohol challenge data on
412 Australian twins was performed to explore the possibility that smoking
may diminish or moderate the intoxicating effects of alcohol. The authors
found history of smoking to be strongly associated with self-reported intoxication
after alcohol challenge in women (women: r= -0.44 + 0.08; men: r= -0.21
+ 0.08), comparable with self-reported average weekly consumption of alcohol,
which was more strongly associated in men (women: r= -0.37 + 0.07; men:
r= -0.54 + 0.06). Structural equation model fitting indicated a strong association
between heavy drinking and smoking, but the association between smoking
and post-alcohol intoxication remained even when the effects of heavy drinking
were controlled for. These results prompt the question of whether smoking
cigarettes directly influences the transition from moderate to excessive
use of alcohol by diminishing feelings of alcohol intoxication. Madden,
P.A.F., Heath, A.C., Starmer, G.A., Whitfield, J.B., and Martin, N.G. Alcoholism:
Clinical and Experimental Research, 19(5), October, 1995.
Fatal Consequences of Cocaine and Opiate Use Cocaine, often with
opiates (predominantly heroin) and ethanol, caused almost three-fourths
of accidental fatal drug overdoses in New York City in 1990 through 1992.
This study assessed all 1986 cases in that period using data collected in
the Office of Chief Medical Examiner. This study excluded intentional (suicidal)
fatal drug overdoses. Cocaine with opiates caused 752 (37.9%) deaths. Cocaine
without opiates caused 629 (31.7%) deaths while opiates without cocaine
caused 503 (25.3%) deaths. Drugs other than cocaine or opiates, predominantly
benzodiazepines and antidepressants, caused 102 (5.1%) deaths. The highest
cocaine overdose rates were found among African-American and Latino males.
Rates of opiate overdose without cocaine did not differ in regard to race/ethnicity
except for low rates among Asians. Males had higher overdose rates than
women for all classes of drugs. The highest rates for cocaine and/or opiates
were found among victims 35-44 years of age. The rates of overdose from
cocaine and opiates increased from 1990-1992. There was a less pronounced
but steady increase of opiate overdoses over that period of time. There
was a marked increase of cocaine overdoses in 1991 followed by a slight
decrease in 1992. The rates of overdoses from drugs other than cocaine or
opiates showed no increase over time. Cocaine is the leading cause of accidental
drug overdoses, unlike in the early 1980's when opiates prevailed as a cause
of death. African-American and Latino males may be particularly susceptible
to cocaine overdoses because of their exposure to crack in poor neighborhoods.
This points to the urgency of targeting drug treatment and police interventions
to these high risk areas. Tardiff, K., Marzuk, P.M., Leon, A.C., Hirsch,
C.S., Stajic, M., Portera, L., Hartwell, N., Accidental Fatal Drug Overdoses
in New York City: 1990-1992. The American Journal of Drug and Alcohol Abuse,
22 (3), 1996.
Reciprocal Relationships among Drug Use, Peers, and Beliefs This
study examines the assumptions of interfactional theory which posits a reciprocal
relationship among drug use, association with drug using peers, and beliefs
about drug use. Five waves of longitudinal data from the Rochester Youth
Development Study were analyzed. Results largely supported the hypotheses,
although the effect from drug use to peer drug use was slightly larger than
from peer use to drug use. The effects of beliefs on drug use was relatively
weak although the two variables were reciprocally related. These findings
have important implications for theory development and intervention strategies.
Krohn, M.D., Lizotte, A.J., Thornberry, T.P., Smith, C., and McDowall, D.
Reciprocal Causal Relationships among Drug Use, Peers, and Beliefs: A Five-wave
Panel Model. Journal of Drug Issues, 26(2), pp. 405-428, 1996.
Substance Use and Suicide Attempts among Runaway and Homeless Youth
Researchers at RTI examined how youth suicide attempts are associated with
youth and familial substance use among a nationally representative sample
of runaways and homeless youth (RHY) residing in shelters, and a multi-city,
purposive sample of RHY found on the street. Analyses revealed that, after
controlling for key demographic characteristics, youth who had used substances,
(particularly sedatives, hallucinogens, and inhalants), were much more likely
than those who had not used substances to have attempted suicide. In addition,
after controlling for their own substance use, youth with family members
who had used substances were twice as likely as those without such family
members to have ever attempted suicide. This study suggests the importance
of developing and focusing suicide prevention efforts on RHY known to have
used substances and to have substance-using family members. Greene, J.M.
and Ringwalt, C.L. Youth and Familial Substance Use's Association with Suicide
Attempts among Runaway and Homeless Youth. Substance Use and Misuse, 31(8),
pp. 1041-1058, 1996.
Immediate Impact of Thirty-Two Drug Abuse Prevention Activities Among
Students at Continuation High Schools Continuation (i.e. alternative)
versus comprehensive (i.e. regular) high schools form a natural demarcation
of youth who are at relatively high or low risk for substance abuse in the
State of California. Those teenagers who are unable to remain in the regular
school system for reasons including substance use are transferred to a continuation
high school. Generic comprehensive social influence drug abuse prevention
activities are less likely to be effective for use with these at risk youth.
Thus, both classroom and self-instruction (main mode of instruction at continuation
high schools) versions of 16 activities derived from different theoretical
sources were tested and ranked on immediate outcome variables. Students
from six continuation high schools were provided with a pretest-activity-posttest
"component study" protocol. The scores on perceived quality ratings
were standardized and averaged to permit easy comparisons across lessons.
While yielding similar knowledge changes, students who received the health
educator led activity consistently reported higher scores on perceived quality.
Social influence-oriented lessons, in general, were rated relatively low
perceived quality. The present approach assisted in selection of the lessons
with the greatest overall immediate impact. Sussman, S., et.al. Immediate
Impact of Thirty-Two Drug Abuse Prevention Activities Among Students at
Continuation High Schools. International Journal of the Addictions, In Press.
Substance Abuse Disorders Among Runaway and Homeless Youth This study
used systematic sampling methods to recruit a sample of 432 homeless youth
from both service and natural 'hang-out' sampling sites in Hollywood. The
interview procedures relied on participants' self-reports. According to
DSM-III criteria, 71% of the respondents were classified as having an alcohol
and/or illicit drug abuse disorder. Age and gender were not significantly
associated with risk of having an alcohol or drug abuse disorder. The cumulative
length of time a youth spent without a consistent place to live was found
to be positively associated with the risk for a diagnosis with either disorder.
Kipke, M.D., Montgomery, S.B., Simon, T., Iverson, E.F. Substance Use &
Misuse, 32, pp. 7-8, 1997.
Results indicated extremely high prevalences of mental health problems among
homeless youth as compared with corresponding rates of mental health problems
found among housed youth in previous studies. Prevalence of mental health
problems differed by age and ethnicity. African-Americans were at lower
risk of suicidal thoughts and self-injurious behavior than were youth of
other ethnicities. Older youth and females were at increased risk of depressive
symptoms and younger youth were at increased risk of self-injurious behavior.
Risk factors for drug abuse disorder included ethnicity other than African-American,
homelessness for one year or more, suicidality, self-injurious behavior,
depressive symptoms, and low self-esteem. The study suggests the need for
street-based and non-traditional mental health services targeted toward
these youth. Unger, J.B., Kipke, M.D., Simon, T.R., Montgomery, S.B., and
Johnson, C.J. Homeless Youth in Los Angeles: Prevalence of Mental Health
Problems and the Relationships Between Mental Health and Substance Abuse
Disorders. American Journal of Community Psychology, In Press.
The histories of the youths were examined in terms of violence, perpetration
of violence and fear of violence in association with gender, ethnicity,
age, and length of time homeless. Respondents reported having experienced
a wide range of violent events and attacks. Levels of exposure to violence
were similar for males and females. However, females were more likely to
report having been sexually assaulted and less likely to have used a knife
to attack or stab someone. There were differences between ethnic groups
on some exposure measures. Exposure to violence was positively associated
with cumulative length of time homeless, and inversely associated with age.
Kipke, M.D., Montgomery, S., Simon T. and Iverson E. Homeless Youth and
their Exposure to and Involvement in Violence while Living on the Streets.
Journal of Adolescent Health, In Press.
Prevention of Steroid Use in Adolescent Athletes A randomized prospective
trial involving 31 football teams in the Portland, Oregon area was recently
conducted. Seven hundred two adolescent football players received seven
weekly 50-minute class sessions delivered by coaches and student team leaders
addressing anabolic androgenic steroid (AAS) effects, sports nutrition,
and strength training alternatives to AAS use, drug refusal role play, and
anti-AAS media messages. Seven weight room training sessions were taught
by research staff. Compared with 804 players from control schools, the experimental
subjects at 9- or 12-month follow-up had increased understanding of AAS
effects, greater belief in personal vulnerability to the adverse consequences
of AAS, improved drug refusal skills, less belief in AAS-promoting media
messages, increased belief in the team as an information source, improved
perception of athletic abilities and strength training self-efficacy, improved
nutrition and exercise behaviors, and reduced intentions to use AAS. Effects
of a Multi-Dimensional Anabolic Steroid Prevention Intervention. The Adolescent
Training and Learning to Avoid Steroids (ATLAS) Program. Goldberg, L., Elliott,
D., Clarke, D.N., MacKinnon, D.P., Moe, E., Zoref, L., Green, C., Wolf,
S.L., Greffrath, E., Miller, D.J., and Lapin, A. JAMA, 276 (19), pp. 1-9,
November 20th, 1996.
Effects of Chronic Cocaine Use on Physical Health The effects of
chronic cocaine use by the late twenties on physical health by the mid thirties
was studied in a longitudinal cohort from the general population. Among
males, chronic cocaine use increased physical health problems, when controlling
for possible confounding factors. Poor health also contributed to continued
cocaine use. Chronic users experienced the most adverse consequences. Chen,
K., Scheier, L.M., and Kandel, D.B. Effects of Chronic Cocaine Use on Physical
Health: A Prospective Study in a General Population Sample. Drug and Alcohol
Dependence, 43, pp. 23-37, 1996.
Polydrug Use and DSM-IV Alcohol Abuse and Dependence among Youth
In a study of 176 adolescent drinkers with diagnoses of alcohol abuse (n=57)
or alcohol dependence (n=61) or no alcohol diagnosis (n=58) based on a modified
form of the Structured Clinical Interview for the DSM, researchers at CEDAR,
the Center for Education and Drug Abuse Research at the University of Pittsburgh,
investigated patterns of polydrug use, particularly combinations involving
alcohol with other drugs. Lifetime histories of alcohol and other drug use
were assessed, and frequency of use of specific alcohol-drug combinations
was determined. Subjects with alcohol abuse and dependence diagnoses reported
using greater numbers of illicit drugs than subjects without an alcohol
diagnosis; recent polydrug use was higher among those with these diagnoses.
Patterns of age of onset of psychoactive substance use followed those observed
by prior researchers (i.e., alcohol, followed by marijuana, followed by
other drugs). The most common alcohol-drug combination was alcohol with
marijuana (reported by 58 percent of the sample), followed by alcohol with
hallucinogens (16 percent). Frequency and extent of polydrug use increased
with age and increased with increasing levels of behavioral under control
and negative emotionality. Martin, C.S., Kaczynski, N.A., Maisto, S.A.,
and Tarter, R.E. Polydrug Use in Adolescent Drinkers with and without DSM-IV
Alcohol Abuse and Dependence. Alcoholism: Clinical and Experimental Research,
20(6), pp. 1099-1108, 1996.
Nicotine Withdrawal In Women Associations between self-report symptom
profiles for nicotine withdrawal, personality (TPQ, EPQ-R), lifetime history
of psychopathology, and smoking history were examined in data obtained from
553 female adult Australian twins (246 regular smokers), aged 32-48, who
had participated in a telephone interview survey that included lifetime
assessments of smoking history, nicotine dependence and withdrawal. 202
respondents were from high-risk pairs where either the respondent or the
respondent's cotwin had reported a lifetime history of alcohol dependence;
351 were from control pairs. Latent class analysis was used to identify
subtypes ('classes') of smokers reporting similar withdrawal symptom profiles.
Three major classes were identified which appeared to represent a continuum
from mild to severe nicotine withdrawal. Smokers from the severe withdrawal
class were best characterized by hands shaking and by the prominence of
depressive features during withdrawal. There were marked increases in lifetime
alcohol dependence rates as a function of severity class. In contrast, significantly
elevated rates of major depression, conduct disorder, and anxiety disorder
were observed only among smokers from the most severe withdrawal class.
With the exception of Neuroticism, personality factors were more closely
related to the initiation of regular smoking than to the development of
withdrawal symptoms. Madden, P.A.F., Bucholz, K.K., Dinwiddie, S.H., Slutske,
W.S., Bierut, L.J., Statham, D.J., Dunne, M.P., Martin, N.G., Heath, A.C.,
and Phil, D. Addictions, In Press.
Development of a School-Based Drug Abuse Prevention Curriculum for High-Risk
Youths This paper presents the rationale for and the description of
the empirical curriculum development process in Project Towards No Drug
Abuse (Project TND). First, the target population is described, continuation
high-school youths who are at high risk for drug abuse. The rationale for
developing a classroom-based curriculum tailored for them is also provided.
Second, a brief description is provided of state-of-the-art generic social
influences drug abuse prevention programming, which has been found to be
the most effective among young adolescents. There is a need to consider
other prevention activities, particularly those that include motivational
variables, to maximize prevention efforts among higher-risk youths. Third,
five types of curriculum development studies are discussed that led to a
curriculum that is being implemented with continuation high-school students
at schools in five counties in southern California. Finally, the contents
of the final curriculum product is provided which consist of motivation,
skills-training, and decision-making components. Sussman, S. Development
of a School-Based Drug Abuse Prevention Curriculum for High-Risk Youths.
Journal of Psychoactive Drugs, Vol. 28(2), April-June 1996.
Key Qualities for Achieving a 96.6 Percent Follow-Up Rate in a Study
of Drug Abusers. The St. Louis Effort to Reduce the Spread of AIDS Study
(ERSA) aimed to reduce the spread of HIV among St. Louis' most vulnerable
drug-using population while improving drug abuse treatment. As part of ERSA,
researchers utilized a three-stage tracking strategy to follow out-of-treatment
drug abusers for an 18-month longitudinal study. There were 479 ERSA subjects
interviewed at baseline who were eligible for reinterview at the terminal
18-month interview; at follow-up, 454 persons had a complete interview (96.6%).
The three-stage tracking strategy, consisting of phone tracking, systems
tracking (using private and public databases, such as national credit information,
social service data, and criminal justice data), and field tracking (visits
by members of the research team to residents and "hang outs")
-- coupled with patience, persistence, enthusiasm, creative team work, time,
and money for remuneration (to the individual, the family, and as a bonus)
-- were instrumental in achieving the 96.6% follow-up rate. Two particular
qualities stood out from the others: persistence (not giving up) and creative
team work. The researchers identified an experienced and enthusiastic staff
who could work together as the most important factor for achieving the study
goals. In addition, when the hard-to-reach respondents were compared on
the basis of gender, race, age, education, psychiatric status, and employment
status to those less difficult to find, only employment status was associated
with being hard-to-reach. Cottler, L.B., Compton, W. M., Ben-Abdallah, A.,
et al. Achieving a 96.6 Percent Follow-Up Rate in a Longitudinal Study of
Drug Abusers. Drug and Alcohol Dependence, 41: pp. 209-217, 1996.
A General Statistical Model for Detecting Complex Trait Loci Using Affected
Relative Pairs in a Genome Search Family, twin, and adoption studies
of substance abuse and dependency have demonstrated a significant role of
genetic determinants. In the case of opioid dependency, using family studies
and epidemiological data, the estimates of the heritability of opioid dependency
is as high as 80 to 90%. These family studies justify the more detailed
search of the human genome for the existence and exact location for susceptibility
genes underlying opioid dependency. Such searches already have been undertaken
for alcoholism. The search of the human genome for susceptibility genes
is a difficult and expensive process that requires elaborate and powerful
statistical methods to deal with the high dependency among DNA segments
and the large number of such segments. Novel molecular techniques such as
Genomic Mismatch Scanning (GMS) are emerging and promising to reduce the
expense of the full genome search. But the statistical methods appropriate
to the newer molecular techniques also must be developed. The current paper
develops a general statistical model and test that can be used with traditional
molecular techniques such as markers as well as the emerging GMS procedures.
The model and test are designed to handle realistically complex genetic
etiology and any mixture of relative types such as siblings, cousins, and
grandparent-grandchildren, and also in the presence of phenocopies (i.e.,
misdiagnosis). Using affected pairs, the exact test controls for the elevated
probability of false rejection of the null hypothesis when the entire genome
is searched. Smalley, S.L., Woodward, J.A., Palmer, C.G.S. A General Statistical
Model for Detecting Complex Trait Loci Using Affected Relative Pairs in
a Genome Search. American Journal of Human Genetics, 58, pp. 844-860, 1996.
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