I'm no psychologist, but just for fun let's give Sherlock the PCL-R, just to look at his possible sociopathic traits. In the UK, a 30 or above can get you sent to Broadmoor. The average person not in prison allegedly scores about 5.
01. glib and superficial charm: 1
Although Sherlock is often immediately charming, he lets his act drop around people he knows and doesn't let the charade go on for long. Donovan and Anderson are fully aware of his true personality and he sees no need to con them into thinking he's a normal individual with ordinary feelings.
02. grandiose (exaggeratedly high) estimation of self: 2
Sherlock holds himself in very high regard and very rarely second-guesses himself, whether this could damage other people or not.
03. need for stimulation: 2
Clearly.
04. pathological lying: 1
Sherlock is for the most part a fairly honest individual, but one example where he lies about something important for his own ends is when he "drugs" John.
05. cunning and manipulativeness: 0
Sherlock displays very little malicious manipulation. In cases when he manipulates people, such as the wife of the disappeared banker in TGG, it's usually someone who deserves it/from whom he needs information for a good purpose.
06. lack of remorse or guilt: 1
In THoB he shows little remorse for locking John in the lab, but after his deduction about Molly's "new boyfriend" he shows somewhat genuine remorse.
07. shallow affect (superficial emotional responsiveness): 0
He doesn't show emotions, period, which shows honesty and not deception.
08. callousness and lack of empathy: 1
"Will caring about them help save them?" However, as stated above, he does reassure the housemistress in TRF and in the pool scene he expresses regret that people have died in Moriarty's game.
09. parasitic lifestyle: 1
He preys on Molly for things that he needs, but otherwise there is no evidence of this trait.
10. poor behavioral controls: 0
In my (not professional) opinion, Sherlock has a good leash on himself behaviourally. Everything he does is quite calculated and intended.
11. sexual promiscuity: 0
Erm...no.
12. early behavior problems: 0
We don't hear about any, so we can't assume.
13. lack of realistic long-term goals: 0
On the contrary, his life goal of continuing his career for the rest of his life seems quite realistic, at least for him.
14. impulsivity: 2
Leaving the house with no pants on just to annoy his brother, shooting the wall in the flat, beating bodies with a riding crop, heading to a pool where a known criminal mastermind is located with no backup of any kind, and breaking into a government base knowing that there's a possibility of getting caught? Yes, I would say he's impulsive.
15. irresponsibility: 1
See above. He does behave in a responsible manner when the situation calls for it, like offering to get the groceries (even if he didn't really intend to)
16. failure to accept responsibility for own actions: 1
Again, when he gives John the coffee laced with sugar.
17. many short-term marital relationships: 0
No.
18. juvenile delinquency: 0
See item 12.
19. revocation of conditional release: 0
Despite the fanfic, we have no evidence that Sherlock has ever been in jail or rehab, let alone violated terms of his parole.
20. criminal versatility: 0
We haven't seen Charles Augustus Milverton yet.
Total: 12, but I was being quite reluctant to score him with '2's on some things. Does anyone disagree with my rating?