Conference Room A
Neuroscience Center
6001 Executive Blvd., Rockville MD
Attendees:
Moderator: Naimah Weinberg
Our current portfolio was described as very high quality but somewhat limited in number and scope given the significance of the field for future genetics work.
Gap areas included: new investigators, training, pharmacogenetics and studies of endophenotypes, studies of specific drugs (other than nicotine), studies of minority populations to whom previously developed models may not apply, gender, clinical populations and high-risk paradigms. Some of these were characterized as "second generation" studies, building on the previous work on heritability in the general population and helping clarify the mechanisms by which drug use disorders develop. Comorbidity studies and truly developmental approaches are weak or lacking; these studies of progression and stages are key to understanding development of drug use disorders, and have major prevention and treatment implications. Prospective or sequential cohort designs are missing and felt valuable as well. Sufficient sample sizes were a concern. Replication of current studies is needed for validity and credibility in the field. Many of the above recommendations bear on the issue of phenotype definition, on which the whole gene-search enterprise will rest. A paucity of adoption studies limits understanding of gene-environment interaction.
NIDA is not funding any behavior genetic methodology studies, such as high risk sampling designs and two or three locus models being studied by other institutes. A lack of "nosologically-driven" research was noted.
The current portfolio is largely limited to domestic researchers and populations, which may limit the potential yield from studying population isolates.
Cross-fertilization among different researchers and approaches was felt to be absent.
Behavior genetic studies have much to offer beyond establishing heritability. Strong doubts were expressed about the readiness of the drug abuse field at this time to mount a successful candidate gene search. Many issues need to be further resolved first, to which behavior genetics, or genetic epidemiology, can contribute. In fact, the relationship between heritability and gene localization is termed "loose."
Behavior genetics can contribute to definition of preclinical phenotypes. In fact, a recommendation was made to study low exposure dependent individuals, and relatives with related deficits who don't meet full dependence criteria, rather than confining the studies to high exposure and heavily dependent individuals and family members. Genetically informed typological research is urged.
Behavior genetics can play two roles: to inform molecular studies about sample selection (phenotype issues), and to refine and guide what needs to be measured after the population is selected. The drug abuse field is felt to be still dealing with the first task, and not yet ready for the second.
Behavior genetic studies can also clarify issues about gene expression, as drug exposure may suppress or accelerate the expression of ("turn on" and "turn off") key genes.
NIDA Home | Site Map | Search | FAQs | Accessibility | Privacy | FOIA (NIH) | Employment |
|