'.. At the age of fifteen Roy Dieks became youth champion of the Netherlands. Only Jan Timman was younger when he became champion. Three years later, Dieks was number two in the world among the youth. Would he become a grandmaster just like Timman and storm the world top? No, it soon stopped.
Dieks turned out to be a difficult person and had to be treated for that. He passed away at the age of 48. His enormous youth results had already been forgotten by most chess players.
Dieks was still successful at many blitz tournaments. He also played fast chess in those serious games in the KNSB competition. He barely thought about his moves. It was said that he had to be ready on time because he would be picked up by 'the van'. He had been admitted to a psychiatric hospital. That that was really the reason for his 'fast game' seems unlikely to me.
Karel van der Weide, teammate at Watergraafsmeer, wrote in his memoriam in the federation magazine: "Life is not easy for everyone and the years of taking heavy medicines had taken its toll. Not only had Roy gained many kilos, the medication was also aimed at 'softening' his emotions [https://en.wikipedia.org/wiki/Antip... , commonly known as tranquilizers]. Win or loss seemed to have lost their meaning when you played against him. Roy lit a cigarette and waited for the next match. Maybe it's just, if you used to fight people like John Nunn, Slavoljub Marjanovic and Aleksander Sznapik over the board, it must actually be unacceptable to lose to a random wood pusher on club night. ” ..'
schaaksite.nl, author Johan Hut, 2018 (in Dutch)
I didn't understand