Polygraph tests can be said to be “neutralized” by a subject or subjects through drugs or pain. Its similar in a manner to an insurance agency that insists that an auto immobilizer can never be beaten. Human nature being what it is – if a person is determined and especially if there is money or the fear of incarceration involved – its always open and a matter to time, effort and sometimes money. Usually though a subjects responses will be “noticeable” and”noticeably high” and as well termed “flat”.
In the case of the Zodiac Allen had reportedly stockpiled his daily medications of Valium tranquillizers and pilfered Thorazine , a medication prescribed for extreme paranoia , from the dispensary where he had conveniently worked. “Thorazine was for the really psychotic patients”. it was said by experts in this case. “It would not be a common and everyday drug that they handed out. “ But then again he would have access to the dispensary – perhaps even ready access during coffee time periods , break times and lunch time. Then again he was being given Valium itself and all he would of had to do simply in essence was to save it up and stockpile it- perhaps all magnified by higher time periods of anxiety to which greater doses of the drug would simply be prescribed.