The Blades have now failed to win in their last 12 league games and Adams believes some of his players must accept more responsibility for their disastrous season so far.
"Some of these players have got to take responsibility, because they have been here since day one of the season," Adams told BBC Radio Sheffield.
"I'm the fourth manager this season, and from day one it has not been good."
Adams took charge at Brammall Lane at the end of December, replacing caretaker boss John Carver after Gary Speed left to take up the position of Wales manager.
The Blades started the season with Kevin Blackwell as boss before he left in August by mutual consent.
"The fans were singing 'you're not fit to wear the shirt', I cannot disagree with them," he added. "That is as disappointing a result as I have ever had in my career."
The Blades are now 23rd in the Championship and five points from safety.