Pesticides tied to ADHD in children from Harvard SPH on Vimeo.

Marc Weisskopf, Mark and Catherine Winkler Assistant Professor of Environmental and Occupational Epidemiology, discusses a study that finds children exposed to higher levels of pesticides known as organophosphates could have a higher risk of being diagnosed with attention deficit hyperactivity disorder (ADHD).

About the Author

Mark Weisskopf - My research interests mostly come from my background in neurobiology. I am interested in how environmental factors affect the nervous system, as well as the epidemiology of neurologic disorders. Current areas of my work include how environmental exposures relate to:
  • cognitive function
  • psychiatric disorders
  • autism
  • amyotrophic lateral sclerosis (ALS)
  • Parkinson's disease (PD)
Some examples of my current work are exploring how exposure to, e.g., lead, manganese, and air pollution affect cognitive function and psychiatric symptoms; how exposure to Agent Orange and other herbicides used in Vietnam relate to the development of PD; and how formaldehyde and lead exposure relate to the development of ALS.

Although not exclusively, much of my work is conducted within large cohorts. I have worked on risk factors for ALS mortality using the American Cancer Society's Cancer Prevention Study II cohort, which has been the largest prospective cohort study of risk factors for ALS with a cohort size of over 1 million. I have also worked on organochlorine exposures and risk of PD in a nested case-control study within the Finnish Mobile Health Clinic study of over 40,000 Finnish residents. I am currently exploring the relation between air pollution exposures and risk of autism among children of women in the Nurses Health Study 2. I am just beginning the study of Agent Orange and PD, which will be nested within the population of Vietnam era veterans receiving medical care through the Department of Veteran's Affairs. I also work with the Normative Aging Study cohort and the Nurses Health Study 1.

An important direction of my research involves developing new ways of examining impacts on the nervous system. My past laboratory research examined the cellular and molecular mechanisms of plasticity in different areas of the brain, processes that are believed to underlie learning, memory, and emotional regulation at the behavioral level. I am building on this background to develop new biomarkers of effects on the nervous system in humans that may be earlier indicators - and potentially more sensitive ones - of adverse effects. I am the principal investigator of a grant to examine the effects of lead exposure on physiological measures of a simple form of learning: conditioning of the acoustic startle reflex. This form of learning relies on biological processes that are the same as those thought to underlie other forms of learning and memory; is independent of conscious processing and so likely avoids many of the biases inherent in assessing cognitive function by other means; is readily applied in different cultural settings; has direct parallels in animal models, thus facilitating comparison with that literature; and additionally may have important implications for anxiety and other emotional disturbances in humans. In addition, I am exploring the use of brain imaging techniques to examine effects of environmental toxicants on the brain.