Dr Sakata diagnosed Sylvian Aqueduct syndrome, a rare condition involving abnormal eye movements, and sent him home with five types of benzodiazepine tranquillisers. But, within a couple of months, his conditioned worsened.
"I just felt like I was going nuts," he said.
Douglas returned to New Zealand where he met Taranaki doctor Graeme Judson and Auckland neurologist Dr David Hutchinson. The experts said he should never have been given the highly addictive drugs.
Douglas was referred to drug and alcohol rehabilitation where he experienced "movie like" withdrawal symptoms.
Two years later, Douglas had regained his strength, balance and mental wellbeing.
He prepared a medical malpractice case against Dr Sakata, which was presented in the Tokyo District Court in 2007. Douglas said he had become addicted because he was prescribed drugs without informed consent and Dr Sakata neglected to monitor his condition.
Douglas lost his case but appealed it in the Tokyo High Court two years later. That was also rejected. He tried to take his case to the Supreme Court but it was dismissed because it did not meet requirements.
Douglas says his fight for justice will never stop. He has created a website for people in similar situations and is writing a novel to build awareness.
Visit Wayne Douglas' website at www.benzo-case-japan.com
