A study of inner-city children comparing the impact of poverty with that of prenatal cocaine exposure adds to the growing body of evidence that prenatal cocaine exposure alone does not significantly impact children’s cognitive development, while poverty has an adverse effect. The study was published in the December 1999 issue of the Journal of Developmental and Behavioral Pediatrics.

The area of prenatal cocaine exposure has generated considerable controversy. Some early research suggested adverse effects but more recent research has failed to confirm such effects.

" We became interested in [studying the impact of maternal cocaine use] because of the whole hurrah about [cocaine-exposed] kids sitting in the corner and shaking and being emotionally unresponsive and irreparably damaged," said neonatologist Hallam Hurt, M.D., principal investigator. " We thought it was a very important question because we work at an inner-city hospital, and we wanted to know what evaluations we should be performing on these children. We started out with the hypothesis that there was damage, but what we found was there was not anything significant."

The study was conducted at Albert Einstein Medical Center in Philadelphia. It is part of a 10-year longitudinal study of a cohort of 219 inner-city children. The research has been supported by the National Institute on Drug Abuse (NIDA) and the Albert Einstein Society of the Albert Einstein Health Care Network. NIDA recently denied further funding.

Although the findings suggest that prenatal cocaine exposure does not adversely impact subsequent cognitive development, they do not address the adverse effects of cocaine use on pregnancy, for which there is evidence of increased risk of preterm delivery and premature detachment of the placenta, Hurt noted. She stressed that she does not want her research to be used as a rationale for saying it’s all right for women to use cocaine during pregnancy.

She noted that over the last decade of tracking the cohort, she and colleagues have conducted a " whole battery of tests" examining the impact of prenatal cocaine exposure without finding evidence that it causes long-term developmental deficits. She does not rule out the possibility that " there is something subtle." But, she added, " we went looking for a number of subtle differences in a small number of children" but found that " a huge number of children in America, the inner-city children, are in trouble, and at a very young age. And that is important."

Those convinced that prenatal exposure is harmful, including NIDA Director Alan Leshner, Ph.D., have suggested that better outcome measures will eventually identify and quantify adverse outcomes attributable to prenatal cocaine exposure. " I promise you there is not no effect, but the question is how subtle is it and how can we identify and help those kids who are affected without stigmatizing an entire cohort of kids," Leshner asserted. " This requires a level of sophistication and laboratory approach that is very elaborate."

Although the earlier image of the horribly damaged " crack baby" was wrong, said Leshner, " you have to be careful you don’t swing the pendulum entirely in the other direction. First you had inappropriate hysteria and now we have inappropriate surety. And the truth is the answer is in between."

There is no doubt, he added, that " socioeconomic status is the biggest risk factor for virtually any adverse outcome you can have developmentally. But the fact that poverty is powerful does not mean these other factors don’t have subtle effects. We don’t want to create a polarity that doesn’t exist."

Hurt is concerned that NIDA’s recent rejection of further funding for her long-term research may reflect institutional bias against continuing to support scientists who fail to find that prenatal cocaine exposure (or other forms of drug abuse) has damaging effects. As evidence, she cited a June 1998 NIDA review of her research in which one reviewer wrote that " a major limitation of this study [to date] has been repeated inability to find any differences between the cocaine-exposed and non-exposed groups." Although the reviewer cited other objections, such as sample size, the comment, said Hurt, reveals a tendency among some to discredit findings that don’t uphold conventional wisdom, regardless of the research’s scientific merits.

Asked about the possibility of such bias in research funding, NIDA’s Leshner dismissed the remark, commenting that " the peer review system gives verbatim reviews and that is surely out of context. I don’t find that a particularly useful comment on Hurt’s part. That certainly is not a decisive factor in what gets funded."

Hurt defended her research, noting that the analytic tool employed in this study, the Goodman Lock Box is " a fairly refined instrument" and that the findings could not be attributed to imprecision. " The data are the data," said Hurt.

Hurt said other data strengthen the conclusions of the current study. For example, she found no differences in a standard battery of pediatric neurological tests administered to six-year-old cocaine-exposed and non-exposed children.

Marc Galanter, M.D., is a consultant to APA’s Council on Addiction Psychiatry and president of the American Society of Addiction Medicine. " This is one study that adds to the consensus that by and large does not support perinatal damage from cocaine except in relation to other covariates such as diet, smoking, and the like," said Galanter. Although it " did not quantitate specific covariates such as alcohol use and cigarette smoking, it is a useful addition to the research literature."

The study found no difference in problem-solving ability at age 3.5 years between a group of 72 cocaine-exposed, low-income children and a group of 81 nonexposed controls. No differences were found in a follow-up at age 4.5 years that looked at 61 of the cocaine-exposed children and 68 controls. But when scores of both the exposed and nonexposed low-income children were compared with scores of middle-class children, the data revealed that poverty has a severe, adverse effect on cognitive development.

In order to be included in the cocaine-exposed group, the children’s mothers had to have used cocaine frequently; those who used cocaine in only one trimester were excluded. Because use of tobacco, marijuana, and alcohol is common in inner-city communities, concurrent use of these substances was not an exclusionary factor, but concurrent use of other substances was. Preterm infants, those with fetal alcohol syndrome, and those with birth asphyxia were excluded, as were those with any identifiable developmental disorder.

Researchers categorized 19 possible behaviors used in exploring the Goodman Lock Box into three main outcome measures; aimless actions, competence, and mental organization. On every measure there was no difference between the cocaine-exposed and control groups. On most of these measures, however, the low-income children scored substantially lower than middle-class children.

The Goodman Lock Box is a large red box with two rows of five compartments. Each of the 10 compartments has a blue door and a unique lock, and inside each compartment is a different toy, varying from a ball of clay to a music box and toy cars. The box is placed in front of children who are invited to play with it, but otherwise given no instructions.