Residual Effects of Abused Drugs on Behavior, 101

ing skills, undergo major developmental changes. A need exists to present data concerning the possible deleterious effects of a specific drug or drug combinations that might occur at a particular developmental stage in the formation of intelligence, emotional functioning, or social functioning. This information might be of help in remediation programming. If it can be demonstrated, for example, that a particular drug has a long-lasting residual effect on a specific behavior such as learning, impulse control, or motor activity, the parent or teacher’s early knowledge of this information may help in understanding the child’s maladjustment or difficulty in coping. Analysis of Subcomponents of Behavior. If residual drug effects can be found in drug-abstinent children or adolescents, it is then useful to evaluate the components of certain cognitive skills, such as types of memory deficits, that may provide important information concerning the ways drug-abstinent children differ from drug-nonabusing children. Of paramount importance is the complete description of types of specific performance errors. For example, brain-impaired individuals can have many cognitive memory deficits, but these failures may occur for different reasons. Korsakoff's patients have difficulty recognizing information (declarative memory) but can acquire new skills (procedural memory), whereas persons with Huntington’s disease show a generalized impairment in memory but fail because of deficits in procedural learning rather than failures in recognition (Mat-tone et al. 1984). Oscar-Berman (this volume) provides additional descriptions of types of errors made by Korsakoff's patients. Further, information of specific learning deficits in drug-abusing children may help uncover potential differences between the maturing right and left hemispheres. Adult alcoholics have difficulty performing visual-spatial tasks, which are the hallmark of right hemisphere damage in patients with documented pathology of this brain area. Yet most research has provided little evidence of greater rightthan left-hemisphere damage. It remains to be clarified whether drug-abstinent children, whose cortices are less mature, make the same types of errors that reflect a generalized brain dysfunction in adults. Many subclinical or “soft” signs seen in abstinent drug abusers may be more readily demonstrated if specific tests or a standardized and computerized neuropsychological test battery were available. Traditional testing batteries such as the Halstead-Reitan or Luria-Nebraska, used primarily for brain-damaged individuals, may be insensitive to drug-induced impairments. Lucki and Rickels (1986) have demonstrated that psychometric tests such as symbol copying and digit span did not reveal any significant deficits in subjects who had been taking benzodiazepines (BZ) chronically for at least 5 years. A test that measures visual perception thresholds, critical flicker