The man, who also is unable to speak and was considered to be at risk for self-destruction, resides in an assisted living facility in Malmo, Swedish news agency TT/The Local reported Thursday.
"I have never heard of anything like it. Our investigators and inspectors are very experienced, but all have been deeply shocked. This treatment is illegal," said Christer Neleryd of the National Board of Health and Welfare.
The man's supervising physician gave instructions to bind the man's hands behind his back by tying his jumper at the elbows with a sock, The Local reported.
"Coercive measures may be taken in an emergency and for short periods. This situation is not close to meeting the criteria," said Neleryd.
Although the man had on occasion become agitated, and hit and cut himself on the face, the board said he could not be considered to have presented a danger to his health and well-being.
The district of Hyllie was told to make sure the bindings stop and to submit a report by November, the news agency said.
"We will then have a look at what they have done, and see if we are satisfied. If we are not then (a court) could impose an injunction (and) a fine, if necessary," said Neleryd.