“The most severe neuropsychological consequence of dioxin exposure is excessive suicides, which has been demonstrated among exposed Vietnam Veterans, chemical production workers in the U.S. and European countries, forestry workers, and railroad workers. Another severe consequence is the excessive death rate from accidents found among the dioxin-exposed chemical production workers and Vietnam Veterans, representing either motor neuron malfunction or suicide in disguise.

“In 1977, the Working Group of the International Agency for Research on Cancer found that neurological and behavioral changes were among the most frequently reported effects in studies of exposures to 2,4,5-T (IARC, 1977a). IARC identified 6 out of 7 different populations occupationally exposed to chlorinated phenolic compounds where neuropsychological symptoms such as neurasthenic or depressive syndromes were established (IARC, 1977b). IARC noted that PNS damage was also found in the same 6 dioxin-exposed populations, including polyneuropathies, lower extremity weakness, and sensorial impairments (sight, hearing, smell, taste). In 1986, the IARC clearly restated it’s finding that dioxin had been found to be associated with peripheral neuropathies and personality changes (IARC, 1986).

“The evidence from the 1990 Ranch Hand study (Thomas, et al., 1990) is particularly compelling in demonstrating CNS damage from Agent Orange exposure.

“Significant psychological deficits were found among Ranch Hand veterans in several subscales in a battery of psychological tests. In contrast, none of the typical dioxin-related psychological deficits were ever found in statistical excess among matched controls. Ranch Hand Veterans experienced a statistically significant excess of great or disabling fatigue during the day, a condition found among many other populations exposed to dioxin.

“Borderline statistically significant verified psychological disorders were found for the category "other neuroses. A series of tests found a borderline statistically significant excess of Ranch Hands experienced depression, somatization, and the severity of psychological distress. Antisocial and paranoid scores for the Ranch Hands were significantly higher, and the psychotic delusion score was marginally significantly higher for Ranch Hands.

“CNS effects, other than neuropsychological deficits, were also found among Ranch Hand veterans (Thomas, et al., 1990). When Ranch Hand veterans or controls that had known past exposures to insecticides were excluded from one analysis (so that neurological findings could be attributed solely to Agent Orange), Ranch Hand veterans exhibited significantly elevated relative risk for cranial nerve dysfunction. Analyses disclosed marginally more balance/Romberg sign (standing without swaying when eyes closed and feet together) and coordination abnormalities for Ranch Hand veterans.

“The VA proposed exclusion of peripheral neuropathies that only become evident 10 or more years after service in Vietnam, on the assumption that such a neuropathy could not be associated with Agent Orange exposure, due to the long interval from exposure.

“This assumption contradicts the findings of the OTA, which found that neurological damage is not always detectable clinically, or noticeable by, the sufferer after exposure to a neurotoxic substance such as dioxin. As time progresses or old age approaches, the rate of natural neuronal cell death accelerates, and the results of earlier neurological damage may first become evident, or unmasked (OTA, 1990). The availability of alternate neuronal pathways is reduced, which were formerly responsible for compensating for earlier toxic damage. The OTA specifically noted the importance of research showing the possibility that neurotoxic substances were important in Alzheimer's disease, the degenerative brain disease of old age.”