State of the Art in Substance Use Prevention and Early Intervention: Applications to Pediatric Primary Care Settings

With changes to drug-related policies and increased availability of many drugs, we currently face a public health crisis related to substance use and associated health consequences. Substance use and substance use disorders (SU/SUDs) are complex developmental disorders with etiologies that emerge through the intergenerational transmission of biological, familial, and environmental factors. The family ecosystem both influences and is influenced by SU/SUDs, particularly in children and adolescents. Family dynamics and parent functioning and behaviors can represent either risk or protective factors for the development of SU/SUDs in children. Primary care providers who provide care for children, adolescents, and families are in an ideal position to deliver prevention messages and to intervene early in the development of substance misuse and SUD among their patients. Despite recommendations from the American Academy of Pediatrics, few pediatric primary care providers provide anticipatory guidance to prevent or screen for substance misuse. Many barriers to those practices can be overcome through the integration and application of findings from the field of prevention science and the many lessons learned from the implementation of evidence-based interventions. Consideration of the implications of prevention science findings would help clarify the relevant roles and responsibilities of the primary care clinician, and the benefit of referral to and consultation from addiction specialists. Additionally, the past decade has seen the development and validation of a continuum of evidence-based prevention and early SU/SUD intervention activities that can be adapted for use in primary care settings making wide-spread implementation of prevention feasible. We propose a paradigm shift away from a model based on diagnosis and pathology to one upstream, that of family-focused prevention and early intervention. Adapting and scaling out empirically based prevention and early SU/SUD interventions to primary care settings and removing barriers to collaborative care across primary care, addiction medicine, and mental health providers offer the potential to meaningfully impact intergenerational transmission of SU/SUD — addressing a leading health problem facing our nation.

Developmental Outcomes Among Young Children With Congenital Zika Syndrome in Brazil

IMPORTANCE

Although birth defects in children with congenital Zika syndrome (CZS) are expected to result in significant intellectual disabilities, the extent of delay and profiles of development have yet to be fully described.

OBJECTIVES

To describe the neurodevelopmental profiles of children with CZS and to test whether prenatal and postpartum characteristics were associated with the severity of developmental delays.

DESIGN, SETTING, AND PARTICIPANTS

This is a case series of the trajectories of developmental, behavioral, and medical needs of 121 young children with CZS who were assessed at a specialized rehabilitation center in Recife, Brazil, beginning in January 2018 as part of 5-year longitudinal study. Children were included if they had serologic confirmation of Zika virus and met clinical criteria accompanied by parental report of suspected exposure to Zika virus during pregnancy.

EXPOSURES

Prenatal Zika virus exposure.

MAIN OUTCOMES AND MEASURES

The Brazilian version of the Bayley Scales of Infant and Toddler Development, Third Edition, was administered by trained assessors as part of an initial comprehensive assessment battery. Caregiver interviews and medical record reviews were conducted to gather basic demographic information and medical comorbidities. Linear regression was used to identify potential factors for development.

RESULTS

The sample included 121 young children (mean [SD] age, 31.2 [1.9] months; 61 [50.4%] girls). At age approximately 2.5 years, nearly all children in this sample demonstrated profound developmental delays across all domains of functioning, with a mean (SD) developmental age equivalent to approximately 2 to 4 months (eg, cognitive domain, 2.24 [3.09] months; fine motor subscale, 2.15 [2.93] months; expressive language subscale, 2.30 [2.52] months). A relative strength was found in receptive language, with scores on this scale significantly higher than most other domains (eg, cognition: t = 3.73; P < .001; fine motor: t = 6.99; P < .001). Head circumference at birth was the single strongest factor associated with outcomes across all developmental domains (eg, cognitive: β = 1.41; SE, 0.67; P = .04; fine motor: β = 1.36; SE, 0.49; P = .007).

CONCLUSIONS AND RELEVANCE

The findings of this study provide important information regarding the severity of disability that these children and their families will experience. The findings also establish an initial point from which to monitor developmental trajectories, medical comorbidities (eg, seizures), effectiveness of interventions, and cumulative consequences on families.

Profiles of individual assets and mental health symptoms in at-risk early adolescents

INTRODUCTION

Few studies investigated the combined patterns of individual assets (e.g., social competence, positive identity) and mental health symptoms (MHS) in adolescents. This study examined the patterns of early adolescents' individual assets and MHS and whether identified patterns were associated with later adolescents' outcomes.

METHODS

Participants were 352 (164 boys, 188 girls) adolescents who were primarily African-American and from low socioeconomic status families, participating in a prospective study of the effects of prenatal cocaine exposure from birth in the Midwest United States. Individual assets, using the Developmental Assets Profile, and MHS, using the Youth Self-Report, were assessed at age 12. Substance use, via self-report and biologic assays, early (before age 15) sexual behaviors, and behavioral adjustment were assessed at age 15.

RESULTS

Latent profile analysis indicated four distinctive profiles: low assets with elevated MHS (P1, n = 54, 15.3%); adequate assets with thought and social problems (P2, n = 84, 23.9%); low assets without MHS (P3, n = 101, 28.7%); and high assets without MHS (P4, n = 113, 32.1%). Children in the profile with high assets without MHS (P4) were more likely to have a higher IQ and to be in a more optimal environment (higher parental monitoring and less family conflict) than those in other profiles. Although profiles with MHS were associated with adolescent risk behaviors, this relationship was more pronounced for girls than for boys.

CONCLUSIONS

Girls in the low assets with elevated MHS (P1) should be a primary concern for preventive intervention. Our study demonstrates the heterogeneity of individual patterns of adaptation and maladaptation.

Effects of Behavioral Treatment Modified to Fit Children with Conduct Problems and Callous-Unemotional (CU) Traits

Research suggests that children with conduct problems (CP) and callous-unemotional (CU) traits show a diminished response to behavior therapy, perhaps due to a reward-oriented, punishment insensitive learning style. Children with CP and CU may benefit from personalizing behavioral treatment for them by emphasizing rewards and de-emphasizing punishments. This hypothesis was tested in a sample of 46 children (78.3% boys), ages 7.0 to 12.6 years (M = 9.3, SD = 1.4). All participants met criteria for ODD and ADHD and 63% also met criteria for CD. Participants were oversampled for high CU, but CU scores ranged from average to high. Children received four weeks of modified behavior therapy that emphasized rewards and de-emphasized punishments and four weeks of treatment as usual, which was standard behavior therapy that balanced rewards and punishments. Treatments were implemented in a summer treatment program and compared using a within-subjects design, with order of treatment counterbalanced. Disruptive behavior was equal or slightly higher in modified behavior therapy than in standard behavior therapy on point system measures, but lower on parent weekly ratings. End of treatment ratings showed both treatments produced significant improvements compared to pre-treatment ratings but did not differ from each other. Personalizing behavior therapy for children with CP and CU produced inconsistent findings relative to standard behavior therapy. Behavior therapy is likely to be a necessary part of treatment for children with CP and CU, but treatment personalization efforts may provide some benefit by addressing other deficits shown by these children.

Developmental trajectories of externalizing behavior from ages 4 to 12: Prenatal cocaine exposure and adolescent correlates

BACKGROUND

Although prenatal cocaine exposure (PCE) has been linked with greater externalizing behavior, no studies have investigated heterogeneity of developmental trajectories in children with PCE to date. The present study aimed to: (1) identify developmental trajectories of externalizing problems in childhood by using a person-oriented analytic approach; (2) examine whether trajectories differ by PCE and other environmental and biological correlates; and (3) investigate how trajectories were associated with adolescent substance use and sexual behavior.

METHODS

Adolescents (N = 386; 197 PCE, 187 non-cocaine exposed (NCE)), primarily African-American and of low socioeconomic status, were prospectively enrolled in a longitudinal study at birth. Externalizing problems were assessed with the Child Behavior Checklist (CBCL) at ages 4, 6, 9, 10, 11, and 12. Substance (tobacco, alcohol, marijuana) use, via self-report and biologic assays, and early (before age 15) sexual intercourse were assessed at age 15.

RESULTS

Latent class growth modeling indicated four distinctive developmental trajectories of externalizing behavior from ages 4 to 12: low-decreasing group (32%); moderate-decreasing group (32%); accelerated risk group (14%); and elevated-chronic group (22%). PCE and maternal psychological distress interactively differentiated developmental trajectories of externalizing behavior, which were related to subsequent adolescent substance use and early sexual behavior differently across gender.

CONCLUSIONS

The two high-risk trajectories (accelerated risk and elevated-chronic groups), comprising 36% of the sample, identified in the present study may reflect multi-causality of early substance use and perhaps greater risk for transition to substance use disorders later in development.

Skills attained by infants with congenital Zika syndrome: Pilot data from Brazil

The recent Zika outbreak and its link to microcephaly and other birth defects in infants exposed in utero have garnered widespread international attention. Based on the severity of birth defects the extent of impairment in these infants is expected to be profound; however, virtually nothing is known regarding the developmental and behavioral sequela of congenital Zika syndrome. This pilot study collected parent-reported patterns of development and sleep in 47 infants with confirmed congenital Zika syndrome who are being followed for clinical services at the Altino Ventura Foundation (FAV) in Recife, Brazil. With assistance from clinicians at FAV, caregivers completed Brazilian Portuguese versions of the Ages and Stages Questionnaire, 3^rd edition (ASQ-3) and the Brief Infant Sleep Questionnaire (BISQ). All infants were between 13–22 months of age at the time of the assessment. At 16 months of age, none of the children displayed age appropriate developmental skills. Most (~ 75%) mastered some communication and gross motor skills at around a 6–8-month level. Communication and gross motor skills were relative strengths for the sample, while problem-solving and fine motor skills were relative weaknesses. Sleep was noted to be a problem for around 18% of the sample. In utero exposure to the Zika virus will have lifelong consequences for affected children and their families. Understanding the developmental and behavioral trajectories of affected infants will help identify appropriate family supports to improve quality of life.

Externalizing behavior and emotion dysregulation are indicators of transmissible risk for substance use disorder

BACKGROUND

Psychological items discriminating children of fathers diagnosed with an illicit drug-related substance use disorder and normal controls are indicators of a unidimensional construct termed transmissible liability index (TLI) (Vanyukov et al., 2009). TLI is a highly heritable (Vanyukov et al., 2009; Hicks, Iacono, McGue, 2012) and valid (Vanyukov et al., 2009; Hicks et al., 2009; Kirisci et al., 2013a) measure of childhood liability to substance use disorders (SUDs).

AIMS

This longitudinal study determined whether TLI has incremental validity for predicting SUD beyond commonly measured psychological indicators of risk.

METHODS

TLI and measures of executive cognitive capacity, emotion dysregulation and externalizing disturbance were administered to boys at ages 10-12 and 16. SUD outcome determined at age 22 was assessed as (1) any SUD, (2) the number of drug-specific SUDs, and (3) SUD severity.

RESULTS

TLI predicted SUD beyond the contribution of measures of emotion dysregulation, executive cognitive capacity and externalizing disturbance. The association of emotion dysregulation and externalizing behavior at ages 10-12 and 16 with SUD at age 22 was also reduced to non-significance after controlling for transmissible risk measured by TLI.

CONCLUSIONS

TLI's incremental validity beyond these latter indicators of risk points to its utility for identifying vulnerable youths requiring intervention.

Familiality of addiction and its developmental mechanisms in girls

BACKGROUND

Drug use disorders (DUD) have been theorized to share sources of risk variation with other consummatory behaviors. We hypothesized that common mechanisms exist for familial risk for DUD, physiological maturation and nutritional status in girls. Whereas body fat content must exceed a threshold to enable adrenarche and gonadarche, nutritional status may also be a behavior risk indicator. Impaired psychological self-regulation associated with DUD risk may manifest in early overeating, which could in turn accelerate reproductive maturation, resulting in a greater likelihood of affiliation with deviant/older peers and drug use.

METHOD

The sample consisted of families ascertained through the father who either had (N=95) or did not have (N=130) a DUD, and who had a 10-12 year old daughter and her mother available for study. Correlation, survival and path analyses of three consecutive assessments evaluated the relationships between parental DUD (number of affected parents, NAP), nutritional status (NS, subscapular skinfold measurements and body mass index), sexual maturation (Tanner stage), peer delinquency, and the daughter's lifetime DUD diagnosis.

RESULTS

NAP was positively related to the girls' nutritional status. Longitudinal path analysis indicated mediation of the relationship between NAP and peer delinquency by sexual maturation. The relationship between NAP and sexual maturation is mediated by NS. The effect of sexual maturation at age ∼11 on the girls' DUD risk is mediated by peer delinquency.

CONCLUSION

The data are consistent with mediation of intergenerational transmission of DUD risk in females by elevated nutrition, leading to accelerated maturation, and affiliation with deviant peers.

Correlation of patient-reported outcomes of sedation and sedation assessment scores in critically ill patients

PURPOSE

Patient-reported outcomes (PROs) are recommended as indicators of quality in the intensive care unit. We studied the correlation between PROs of sedation quality and a universal sedation assessment scale in critically ill patients.

MATERIALS AND METHODS

Twenty-nine mechanically ventilated adults admitted to a surgical/trauma or medical intensive care unit requiring continuous infusion sedation for 24 hours or more were prospectively included. Patient-reported outcomes were evaluated through sedation questionnaire 24 hours post-continuous infusion sedation. The primary outcome was the correlation of PROs with Sedation-Agitation Scale (SAS) scores.

RESULTS

Mean (SD) SAS scores per 12-hour nursing shift for propofol (n=179), midazolam (n=42), and dexmedetomidine (n=8) were 3.78 (77), 3.31 (1.1), and 2.98 (0.76), respectively. The mean score for survey questions addressing perceptions of comfort was 5.3 (1, complete comfort; 10, not comfortable at all). Of the patients, 34%, 7%, and 52% would want more, less, or the same amount of sedation, respectively, if this situation were to arise again. Patient perception of comfort correlated with the percent time at goal SAS score; r=0.31 (P<.05).

CONCLUSION

Patient-reported outcomes of sedation correlate with the percentage of time spent in the goal range of scores for a universal sedation assessment scale. These findings represent initial attempts to appreciate the patient's perspective in the management and monitoring of agitation.

Longitudinal modeling of transmissible risk in boys who subsequently develop cannabis use disorder

BACKGROUND

Risk for substance use disorder is frequently transmitted across generations due to significant heritability.

OBJECTIVE

This longitudinal study tests the hypothesis that initial exposure to cannabis in youths having high transmissible risk is a signal event promoting development of cannabis use disorder (CUD).

METHODS

At age 22, 412 men were classified into three groups: (1) lifetime CUD, (2) cannabis use without CUD, and (3) no lifetime cannabis use. Transmissible risk, quantified on a continuous scale using the previously validated transmissible liability index (TLI), along with cannabis use and CUD were documented at 10-12, 12-14, 16, 19, and 22 years of age.

RESULTS

The CUD group scored higher on the TLI before they began cannabis use compared to the other two groups. In addition, a progressive increase in TLI severity was evinced by the CUD group beginning at the time of initiation of cannabis use whereas cannabis users who did not subsequently develop CUD exhibited a decline in transmissible risk following first exposure.

CONCLUSION

Initial use of cannabis potentiates development of CUD in youths who are at high transmissible risk but is inconsequential in youths having low risk. The practical ramifications of these results for prevention are discussed.

Age of alcohol and cannabis use onset mediates the association of transmissible risk in childhood and development of alcohol and cannabis disorders: evidence for common liability

Age at the time of first alcohol and cannabis use was investigated in relation to a measure of transmissible (intergenerational) risk for addiction in childhood and development of alcohol use disorder (AUD) and cannabis use disorder (CUD). It was hypothesized that age at the time of first experience with either substance mediates the association between transmissible risk and subsequent diagnosis of both disorders. The Transmissible Liability Index (TLI; (Vanyukov et al., 2009) was administered to 339 10- to 12-year-old boys (n = 254) and girls (n = 85). Age at the time of first alcohol and cannabis use, and diagnosis of AUD and CUD, were prospectively tracked to age 22. Each standard deviation unit increase in TLI severity corresponded to a reduction in age of alcohol and cannabis use onset by 3.2 months and 4.6 months, respectively. Age at the time of first alcohol use mediated the association of TLI with both AUD and CUD. Parallel results were obtained for cannabis. Whereas transmissible risk is congenerous to both AUD and CUD, its magnitude was 7 times greater in youths who initiated substance use with cannabis. TLI predicts age of first use of alcohol and cannabis that is common to developing both AUD and CUD. The ramifications of these findings for prevention are discussed.

Relation among HPA and HPG neuroendocrine systems, transmissible risk and neighborhood quality on development of substance use disorder: results of a 10-year prospective study

BACKGROUND

Research has shown involvement of hormones of the hypothalamic pituitary adrenal (HPA) axis and hypothalamic pituitary gonadal (HPG) axis in the regulation of behaviors that contribute to SUD risk and its intergenerational transmission. Neighborhood environment has also been shown to relate to hormones of these two neuroendocrine systems and behaviors associated with SUD liability. Accordingly, it was hypothesized that (1) parental SUD severity and neighborhood quality correlate with activity of the HPG axis (testosterone level) and HPA axis (cortisol stability), and (2) transmissible risk during childhood mediates these hormone variables on development of SUD measured in adulthood.

METHODS

Transmissible risk for SUD measured by the transmissible liability index (TLI; Vanyukov et al., 2009) along with saliva cortisol and plasma testosterone were prospectively measured in boys at ages 10-12 and 16. Neighborhood quality was measured using a composite score encompassing indicators of residential instability and economic disadvantage. SUD was assessed at age 22.

RESULTS

Neither hormone variable cross-sectionally correlated with transmissible risk measured at ages 10-12 and 16. However, the TLI at age 10-12 predicted testosterone level and cortisol stability at age 16. Moreover, testosterone level, correlated with cortisol stability at age 16, predicted SUD at age 22.

CONCLUSION

HPA and HPG axes activity do not underlie variation in TLI, however, high transmissible risk in childhood predicts neuroendocrine system activity presaging development of SUD.

Application of person-centered medicine in addiction

This article discusses human individuality within a lifespan developmental perspective. The practical application of an individual differences framework for diagnosis, prevention and treatment of addiction is described. A brief overview of the methods conducive to knowledge development within the rubric of person-centered medicine that are available to practitioners working in office and clinic settings concludes the discussion.

Computer adaptive testing of liability to addiction: identifying individuals at risk

BACKGROUND

Employed as a quantitative measure of substance use disorder (SUD) risk, the transmissible liability index (TLI) can be useful for detecting youths requiring prevention intervention. This study was conducted to develop and evaluate a computer adaptive test (CAT) version of the TLI to identifying individuals at risk for SUD.

METHODS

In the first sample (N=425) of male and female subjects were recruited under aegis of the Center for Education and Drug Abuse Research in Pittsburgh, PA, USA, having a mean age of 18.8 years. A provisional CAT version of the TLI was assessed using simulation procedures. In sample 2, twins were recruited at the 2010 Twinsburg Festival in Twinsburg, OH, USA. The CAT and paper and pencil (P&P) versions of the TLI were administered to 276 twin pairs having a mean age of 19.94 years.

RESULTS

The simulated CAT version of the TLI predicted cannabis use disorder 2 years after initial study with 4% less accuracy (72% vs. 68%) than P&P version but with 78% reduction of items. In the twin sample, the CAT version predicted alcohol and drug use (OR=1.7 [2.1], p<.001) with 64% and 65% accuracy (sensitivity=75% [75%] and specificity=64% [65%]).

CONCLUSIONS

This study demonstrated that the CAT version of the TLI is an accurate and efficient measure of risk for SUD. The CAT version of the TLI potentially affords the opportunity for efficient screening of risk so that timely interventions can be implemented to prevent occurrence of SUDs having frequently lifelong consequences.

Deviant socialization mediates transmissible and contextual risk on cannabis use disorder development: a prospective study

AIMS

This study examined the contribution of transmissible risk, in conjunction with family and peer contextual factors during childhood and adolescence, on the development of cannabis use disorder in adulthood.

DESIGN

The family high-risk design was used to recruit proband fathers with and without substance use disorder and track their sons longitudinally from late childhood to adulthood.

SETTING

The families were recruited under the aegis of the Center for Education and Drug Abuse Research in Pittsburgh, Pennsylvania.

PARTICIPANTS

The oldest son in the family was studied at ages 10-12, 16, 19 and 22 years.

MEASUREMENTS

The transmissible liability index (TLI), along with measures of quality of the parent-child relationship, cooperative behavior at home, social attitudes and peer milieu were administered to model the developmental pathway to cannabis use disorder.

FINDINGS

Affiliation with socially deviant peers and harboring non-normative attitudes (age 16) mediate the association between transmissible risk for substance use disorder (SUD) (age 10-12) and use of illegal drugs (age 19), leading to cannabis use disorder (age 22).

CONCLUSIONS

Deviant socialization resulting from transmissible risk and poor parent-child relationship is integral to development of cannabis use disorder in young adulthood.

Developing an Institutional Informational Base and Bibliographical Clearinghouse

Successful management and implementation of the diverse functions of the International Network of Person-Centered Medicine (INPCM) require a comprehensive and efficient informational base to advance quality of patient care though timely and rapid distribution of knowledge via publications, conferences, and education programs in concert with catalyzing research through systematic efficient data acquisition, storage, retrieval, and analysis. This study describes the structure and functions of the proposed INPCM's information system.

Measurement of the risk for substance use disorders: phenotypic and genetic analysis of an index of common liability

The inability to quantify the risk for disorders, such as substance use disorders (SUD), hinders etiology research and development of targeted intervention. Based on the concept of common transmissible liability to SUD related to illicit drugs, a method enabling quantification of this latent trait has been developed, utilizing high-risk design and item response theory. This study examined properties of a SUD transmissible liability index (TLI) derived using this method. Sons of males with or without SUD were studied longitudinally from preadolescence to young adulthood. The properties of TLI, including its psychometric characteristics, longitudinal risk assessment and ethnic variation, were examined. A pilot twin study was conducted to analyze the composition of TLI's phenotypic variance. The data suggest that TLI has concurrent, incremental, predictive and discriminant validity, as well as ethnic differences. The data suggest a high heritability of the index in males. The results suggest applicability of the method for genetic and other etiology-related research, and for evaluation of individual risk.

Prediction of cannabis use disorder between boyhood and young adulthood: clarifying the phenotype and environtype

Employing a prospective paradigm, this investigation derived the childhood phenotype and the environtype associated with risk for cannabis use disorder. Two hundred and sixteen boys were evaluated between age 10-12 on a comprehensive protocol using self, mother, and teacher reports and followed-up at ages 19 and 22 to determine the presence of cannabis use disorder. The Transmissible Liability Index (TLI) and Non-Transmissible Liability Index (NTLI) were derived using item response theory. Logistic regression was conducted to evaluate the accuracy of the indexes, singly and in combination, to predict cannabis use disorder. The TLI and NTLI together predicted with 70% and 75% accuracy cannabis use disorder manifest by age 19 and age 22. Sensitivity was 75% at both ages 19 and 22, whereas specificity was respectively 51% and 64%. The findings pertaining to sensitivity indicate that SUD risk for cannabis use disorder can be screened in childhood; however, the specificity scores demonstrate that a low score on the TLI does not inevitably portend a good prognosis up to 10 years later.

The specificity of family history of alcohol and drug abuse in cocaine abusers

This study addresses the issue of whether the increased rates of substance-related problems for family members of cocaine abusers are specific for each substance. The present analysis examined the prevalence of problems due to alcohol or drug use separately for mothers, fathers, sisters, and brothers using the Family History Assessment Module. The probands were 343 out-of-treatment subjects with DSM-III-R cocaine disorders who did or did not have additional alcohol and opiate disorders. After accounting for age, race, gender, and antisocial personality, family history of alcohol-related problems had an odds ratio of 1.6 (p <.05) if a participant was alcoholic in addition to abusing cocaine. Specifically, a significantly greater proportion of participants' sisters (p <.001) and brothers (p <.05) had alcohol-related problems if the participant had a history of alcoholism. Among probands who reported opiate abuse or dependence, 38% had relatives with drug-related problems, while participants without opiate abuse or dependence had less than 31% of relatives with drug-related problems (p <.05). However, this association with opiate abuse or dependence and family history of drug-related problems was non-significant after controlling for participants' age, race, gender, treatment status, and antisocial personality diagnosis (odds ratio = 1.4, 95% C.I. = 0.8-2.4). Associations between participants' alcoholism and first-degree relatives' drug-related problems (and vice versa) showed that participants' history of opiate addiction did improve prediction of first-degree relatives' alcohol-related problems, except for participants' brothers. Additional familial risks for alcoholism were seen among siblings of drug abusers who also reported abuse of or dependence on alcohol even after controlling for relatives' ages. Furthermore, parental prevalence of alcohol-related problems were greater when participants had opiate addiction in addition to cocaine addiction. This seems to indicate that opiate addiction in addition to cocaine addiction has particularly strong inheritance patterns. In contrast, parental prevalence of drug-related problems was not greater when participants had alcohol addiction in addition to cocaine addiction. Thus, the cross-substance parent-child familial risk is limited to the dually diagnosed illicit drug.