Further we will see that it is very arguable point.
All cases of healing in Mark can be split into two broad categories: healing itself, and casting out demons and unclean spirits. The former one includes healing from fever, leprosy, paralysis, withered hand, haemorrhage, death, deafness, blindness, and in the latter one there are numerous instances of exorcism.
When Jesus cast out an unclean spirit in Capernaum, it "convulsing him [a man] and crying with a loud voice, came out of him" (Mk 2:26). Whenever we read about demons and evil spirits we must remember that it's a common reference for mentally sick people of ancient and medieval times.
Possessed ones actually had hysteria or various kinds of mental disorders (Crombie, 1964); belief in somebody's divinity could be a shock strong enough to cure themselves. It is important to note that at least in some cases (or even maybe in every one) it was a sick person healing himself, and Jesus was simply an agent, a catalyst.
Crowds gathered around Jesus, for they believed that even a touch of his clothes could remove disease (Mark 5:28). ...