Depends upon the part of the mind the psionicist is going after. I have always divided the mind into three parts: Conscious, the Subconscious, and the Id. I know this is Freud, but it has worked for me.
Even unconscious, I have ruled that a person's mind still may have natural defenses. Also, you might run into a person who has been trained to defend their mind automatically.
Watch the movie Inception. It actually does a very good job of showing how difficult it can be to get into a person's mind who has had their subconscious and id trained to defend themselves. Such person's could have phenomenal bonuses against such attacks, even if unconscious whether from an skull thump, drugs, etc.
And then, what would a person's subconscious and id be like if they are passed out drunk? Now you are really messing with a nasty can of worms. This is something I have only thought of, never dwelled on.
If the person has no such training, even then I ruled their conscious mind still received a +15 bonus to resist. The subconscious gets a +25 bonus, and the id gets a +50 bonus. No matter what anyone would think, it would be very difficult to fool a person's id. Not as hard for the subconscious and conscious minds. Heck, if you really think about, sometimes, even when conscious, your conscious mind can be easily fooled. Just look at the many optical illusions.
Natural things such as fatigue, sleepiness, etc. would probably give a bonus to the psionicist which would, and probably could, negate any natural bonus the conscious mind may have. However, as said, the subconscious mind and the id mind would be more difficult.
Hope this helps, but it probably will cause more confusion than answering any questions. A suggestion would be to google about psychiatry and do some research. I minored in psychology when I was getting my double major in Geography/Geology on my first degree. But I will admit I am not the smartest when it comes to the mind.
rmfr