The Open UniversitySkip to content

Neuropsychological and psychiatric functioning in sheep farmers exposed to low levels of organophosphate pesticides

Mackenzie Ross, Sarah Jane; Brewin, Chris Ray; Curran, Helen Valerie; Furlong, Clement Eugene; Abraham-Smith, Kelly Michelle and Harrison, Virginia (2010). Neuropsychological and psychiatric functioning in sheep farmers exposed to low levels of organophosphate pesticides. Neurotoxicology and Teratology, 32(4) pp. 452–459.

Full text available as:
PDF (Accepted Manuscript) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (355Kb)
DOI (Digital Object Identifier) Link:
Google Scholar: Look up in Google Scholar


The study aim was to determine whether low level exposure to organophosphate pesticides (OPs) causes neuropsychological or psychiatric impairment. Methodological weaknesses of earlier studies were addressed by: recruiting participants who had retired on ill health grounds; excluding participants with a history of acute poisoning, medical or psychiatric conditions that might account for ill health; and exploring factors which may render some individuals more vulnerable to the effects of OPs than others. Performance on tests of cognition and mood of 127 exposed sheep farmers (67 working, 60 retired) was compared with 78 unexposed controls (38 working, 40 retired) and published test norms derived from a cross section of several thousand adults in the general population. Over 40% of the exposed cohort reported clinically significant levels of anxiety and depression compared to less than 23% of controls. Exposed subjects performed significantly worse than controls and standardisation samples on tests of memory, response speed, fine motor control, mental flexibility and strategy making, even after controlling for the effects of mood. The pattern was similar for both working and retired groups. The cognitive deficits identified cannot be attributed to mood disorder, malingering, a history of acute exposure or genetic vulnerability in terms of PON1(192) polymorphisms. Results suggest a relationship may exist between low level exposure to organophosphates and impaired neurobehavioural functioning and these findings have implications for working practice and for other occupational groups exposed to OPs such as aviation workers and Gulf War veterans.

Item Type: Journal Article
Copyright Holders: 2010 Elsevier Inc.
ISSN: 1872-9738
Keywords: organophosphates; neurobehavioural; neuropsychological; cognitive dysfunction; farm workers
Academic Unit/Department: Social Sciences > Psychology in the Social Sciences
Social Sciences
Item ID: 32168
Depositing User: Virginia Harrison
Date Deposited: 01 Feb 2012 17:35
Last Modified: 23 Feb 2016 20:05
Share this page:


Scopus Citations

Actions (login may be required)

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340