A wide variety of toxicants have been found to impair cognitive functi
on. Some such as lead, organophosphate pesticides, and polychlorinated
biphenyls are quite widespread in the environment. Others such as alc
ohol, nicotine, and cocaine are widely used drugs of abuse. Many peopl
e are chronically exposed to these toxicants. Lasting cognitive defici
ts can result, especially after developmental exposure. Considerable r
esearch has been directed at developing pharmacological agents to trea
t the cognitive dysfunction associated with Alzheimer's Disease. Unfor
tunately, other types of cognitive dysfunction, such as toxicant-induc
ed cognitive deficits, have not received the same degree of attention,
despite the fact that they are quite widespread and may be more amena
ble to development of useful therapeutic treatments. Animal models can
be particularly useful because the agents causing these deficits are
known. In addition, for a variety of neurotoxic compounds, information
concerning the nature of the cognitive effect and mechanism of toxic
action can help in development of treatments. Prevention of toxic expo
sure is ideal. Removal from the source of pollution after exposure can
help, but for those who already carry the burden of persistent defici
ts, development of efficacious therapeutic treatments is a necessity.