No less complex than the problems of substance abusing parents are their children's needs. A large research literature exists from epidemiological, family, adoption and twin studies concerning the genetic and environmental risks that put these children at higher risk for a variety of problems (Kumpfer, 1987; Tarter & Messich, 1997; Johnson and Leff, in press). Whether because of in utero exposure to stressors including tobacco, alcohol, or drugs, or to genetic and environmental family risks, children of substance abusers are more frequently described by their parents as being hyperactive and as having difficult temperaments. Clinical studies do not find these children to have significantly more diagnosable attention deficit disorder, but simply to be more active and have a high energy level. McMahon and Luthar (1998) report in a review of developmental issues in children of substance abusers that the two main research findings regarding such children are (1) that they have poorer developmental outcomes (physical, intellectual, social and emotional) than other children, although generally in the low-normal range rather than severely impaired; and (2) they are at risk of substance abuse themselves.
Evidence is increasing that children of substance abusers are at elevated risk for developing substance use disorders at young ages due to familial and genetic factors. Merikangas, Stolar, and their colleagues (1998) report an 8-fold increased risk of drug disorders among relatives of 299 individuals with drug disorders. These findings were reinforced in a second generation study of the children of these drug dependent research subjects (Merikangas, Dierker, et al., 1998). The strongest link was found between substance disorders in offspring (mean age 12 years) with parental substance abuse although the link for psychopathology, particularly anxiety disorders, was similar. Risks of this magnitude place a family history of drug disorder as one of the most potent risk factors for the development of the child and the child's development of drug disorders at an early age. These findings suggest that substance prevention and intervention programs should target offspring of parents with substance use disorders. In fact, children of alcohol and drug abusing parents are at the highest risk of any children for later drug use and other adolescent behavioral health and mental health problems. Research also suggests that some children of substance abusers, like other children of dysfunctional parents, can develop special resilience skills with appropriate adult support (Johnson & Leff in press; Kumpfer, Walker & Richardson, in press).
A number of good literature reviews have been published regarding developmental issues in children prenatally and environmentally exposed to substance abuse (Harden, 1998; Pagliaro and Pagliaro, 1997; Carta et al, 1997). Generally, most research finds that factors in the postnatal environment mediate prenatal factors. It is now recognized that the older a child gets, the more important the home environment is in predicting developmental outcomes, including how the environment interacts with any direct effects of prenatal drug exposure. Women who use drugs during pregnancy are at risk for delivering premature and low birth weight babies. Alcohol appears to have more profound and long-lasting effects on development than do cocaine and other illicit drugs, including serious intellectual and behavioral consequences in many children.
SAMHSA's Center for Mental Health services has found, through an evaluation of its Comprehensive Community Mental Health Services Program for Children and Their Families, that children's mental health problems are closely intertwined with parents' substance abuse, child maltreatment, and other forms of family violence. These grantees serve children with serious emotional disturbances. Evaluation results reveal that over 60 percent of families have had a history of substance abuse, and over half of the families had a history of family violence. Almost one-fourth of children were reported to have been sexually abused prior to entering services, 20 percent of children were reported to have used alcohol and drugs, and 59 percent of children served were described by their caregivers as having one or more risk factors including: physical abuse, sexual abuse, previous psychiatric hospitalization, sexual abusiveness, suicide attempts, drug and alcohol use, and a history of running away (HHS/SAMHSA, 1999).
Babies whose mothers drink alcohol during pregnancy can be born with Fetal Alcohol Syndrome (FAS) or alcohol-related birth disorders. FAS is among the leading known causes of mental retardation in the United States. Infants born with FAS have difficulties with coordination, speech and hearing impairments, and heart defects. Research indicates that there is no known safe level of alcohol consumption during pregnancy, although FAS and related problems are more likely with heavy consumption of alcohol, particularly binge drinking. According to the National Organization on Fetal Alcohol Syndrome, at least 5,000 infants are born with FAS annually and another 50,000 infants demonstrate symptoms of alcohol-related birth disorders (National Organization on Fetal Alcohol Syndrome, no date).
Consumption of illicit drugs during pregnancy also may harm the fetus and may have long-term effects on children. Babies who were prenatally exposed to cocaine or other drugs may experience a range of problems, including some that can be long-lasting and serious. However, these physical and mental deficits are not seen in infants to the extent that earlier expert warnings and media reports regarding "crack babies" had predicted (HHS/NIDA, 1994).
Some researchers have found that more subtle developmental problems, particularly in language skills, can be observed in prenatally drug-exposed children as they age. A recent meta-analysis combining results from eight studies finds that cocaine-exposed infants have, on average, IQ scores that are 3.26 points lower than other children. While the effects of cocaine exposure on IQ were small, medium sized differences (defined as those in which cocaine exposed children's scores were lower than those of other children by between 0.5 and 0.75 standard deviations) were found in receptive and expressive language functioning (Lester et al, 1998). Although the developmental effects are subtle, special education to prevent these children from failing in the school environment could cost up to $352 million per year according to the Brown University analysis.
How much of children's presenting developmental difficulties are due to prenatal injury versus postnatal deprivation continues to be a matter of some debate. In their review, Bernstein and Hans (1994) conclude that it may be the number and persistent nature of threats that best predicts developmental outcomes. That is, more risk factors in place for longer periods in a child's life are most likely to have long lasting and serious negative consequences.