The Impact of Pesticides - Academy Publish

Chronic organophosphate-induced neuropsychiatric disorderChronic exposure to OP has been associated with impaired neurobehavioralperformance in some, but not all, epidemiological studies (Ray and Richards, 2001).Chronic organophosphate-induced neuropsychiatric disorders (COPIND) occurwithout cholinergic symptoms and apparently are not dependent on AChE inhibition(Ray and Richards, 2001; Singh and Sharma, 2000). COPIND usually appears witha delay and persists for a long period possibly suggesting the permanent damage ofthe central nervous system (Savage et al., 1988; De Silva et al., 2006; Tan et al.,2009). The most common symptoms of COPIND include cognitive deficit(impairment in memory, concentration and learning, problems with attention,information processing, eye-hand coordination and reaction time), mood change(anxiety, depression, psychotic symptoms, emotional lability), chronic fatigue,autonomic dysfunction, peripheral neuropathy and extrapyramidal symptoms suchas dystonia, resting tremor, bradikynesia, postural instability and rigidity of facemuscles (Ahmed and Davies, 1997; Davies et al., 2000a; Singh et al., 2000; Ray andRichards, 2001; Salvi et al., 2003; Kamel et al., 2004; Roldan-Tapia et al., 2005;Tan et al., 2009; Jokanović et al., 2011). Suicidality and alcohol intolerance havealso been reported (Davies et al., 2000a). Similar clinical features have also beenreported by soldiers suffering from the Gulf-War Syndrome, which led to the, so farunproven, hypothesis that the illness was caused by chronic exposure to chemicalagents with similar effects to OPs (Gronseth, 2005).Diagnostic criteria for COPIND include (Davies et al., 2000b):- Repeated exposure to organophosphates;- At least four of the following: a) personality change and destabilization of mood,b) impairment of concentration, c) impaired exercise tolerance, d) reduced toleranceto alcohol, e) heightened sensitivity to organophosphates;- At least three of the following: a) exacerbation of “dippers flu”, b) impulsivesuicidal thinking, c) language disorder, d) heightened sense of smell, e) deteriorationof handwriting.With the aim to prove the harm due to chronic OP exposure, Jamal (1997)performed tests of peripheral and autonomic nerve functions in patients withCOPIND. Results obtained in this study showed the absence of damage in somecases of COPIND, while others have shown only a few symptoms.In several epidemiological studies conducted among farm workers and pesticideapplicators, neuropsychological damage accompanied with damage of peripheralnervous system, anxiety and depression were predominant among the poisonedgroup (Steenland et al., 1994; London et al., 1998; Beseler and Stallones, 2008).Agricultural workers tested about 2 years after a pesticide poisoning episode showedsignificantly lower performance in verbal and visual attention, visual memory,sequencing and problem solving (Rosenstock et al., 1991). Levin et al. (1976) founda high level of anxiety in commercial sprayers of insecticides but not in farmers.Savage et al. (1988) showed abnormalities in psychometric testing and motorreflexes. Mild intoxication can also induce COPIND, farm workers with mild OPpesticides intoxication requiring no hospitalization performed worse on tests ofcognitive and psychomotor function than nonpoisoned workers did tested 2 yearslater. During the process of dipping sheep into the basin with insecticide, workersexposed to OP compound developed greater vulnerability to psychiatric disorderssuch as significant anxiety and depression (Jamal et al., 2002; Kamel et al., 2005).Epidemiological study from Spain revealed a link between exposure toorganophosphates and increased suicidal rate (Parron et al., 1996). A literaturereview of mortality and morbidity studies related to suicide among pesticide-AcademyPublish.org - The Impact of Pesticides45