Background: Human exposure to insecticides raises serious public health concerns
worldwide. Insecticides constitute a wide-ranging heterogeneous group of chemicals, most of
which target the nervous system and disrupt neurometabolism and/or neurotransmission. Although
the acute effects of insecticide poisoning in humans are well documented, the chronic
and long-term effects remain difficult to investigate.
Objectives and Method: We sought to review the present state-of-knowledge of acute,
chronic, neurodevelopmental and neurological consequences of human exposure to insecticides.
Results: Animal and epidemiologic studies indicate cognitive, behavioral and psychomotor
alterations in mammals chronically exposed to insecticides. Parkinson’s and Alzheimer’s diseases,
amyotrophic lateral sclerosis, and depression, have been regularly associated with insecticide
exposure. Clinical studies, supported by experiments on animal models, demonstrate
the neurotoxic impact of insecticide exposure during the period of cerebral development, the
developing brain being particularly vulnerable to the action of insecticides. Moreover, detoxifying
systems that are highly polymorph lead to great inter-individual variability in susceptibility
to the neurotoxic effects of insecticides.
Conclusion: Studies on mild chronic exposure to insecticides suggest significant involvement
in the pathogenesis of multifactorial neurological diseases. However, the tardive appearance
of neurodegenerative disorders and the large variability of inter-individual susceptibility to
neurotoxicants make it difficult to assess the relative contribution of insecticide exposure.
Close vigilance should therefore be exercised with regard to possible exposure to insecticides,
particularly during the period of cerebral development.