The Gunners' star has known the Blues forward since his teenage years in the Spanish youth set-up, and Arteta feels some of the criticism directed at his old colleague is unwarranted and unfair.
Torres has scored nine goals in 51 Premier League appearances since swapping Liverpool for Chelsea for £50m in January 2011.
But Arteta feels some of the abuse directed at the Spaniard is harsh.
"I don't like the way he has been treated because I have known him since we were 16, 17, and I really appreciate him," Arteta said on Arsenal.com.
"He is a friend of mine. Obviously, football is like that - it doesn't matter what you have done in the past, it is only what you have done in the last few weeks.
"He has been criticised. Mentally he is a really strong guy even if someone doubts him."
Arteta and Torres are both set to take to the field on Saturday at the Emirates Stadium. Top of the table Chelsea visit north London at Saturday lunchtime, and the two Spaniards are both expected to play key roles for their respective sides.
And Arteta feels his compatriots role as lone striker at Stamford Bridge, further heaps the pressure on the Chelsea forward.
"When you play as a striker and they pay £50m for you, you are under huge pressure," said Arteta.
"And obviously when the ball isn't going in the net, it is even more difficult because people always look at that.
"For a striker, sometimes it is not fair. For a midfielder or a defender it is a bit easier to adapt. For a striker it is tough."