Demons do not exist and spirits are merely 'attitudes'.
Jesus in casting out demons never once used any sort of 'recipe' on any one 'possessed'. possessed means afflicted: "expressed in the mind and consciousness of the "affliction". Medical science has realised that all conditions have their origins in the brain, physically or chemically. Ethiopians believed that malaria was caused by a demon UNTIL a doctor used a PILL to combat the malaria. Jesus appeared to have cast out demons but so many times he "healed them" as if there were no demon.
If you read the story of "Mark 9:24 And straightway the father of the child cried out, and said with tears, Lord, I believe; help thou mine unbelief". You will see that jesus went through the full pattern 'of the time' to cast out this demon, one of which was just an inner ear problem leading to the childs poor balance.
John 16:12 "I have yet many things to say unto you, but ye cannot bear them now". Jesus came not to get caught up in doctrines of devils but to preach the good news. Jesus did not spend time re-indoctrinating every wrong belief of the jews that they incorporated while being captive in persian, babylonian and then roman cultures. But we have the holy spirit to lead us into all truth.
Often the name of jesus has calming effects and praising god can do wonderful things. This mentioning of jesus name to cast out demons is not scriptural.
Luke 10:17 And the seventy returned again with joy, saying, Lord, even the devils are subject unto us through thy name.
Luke 10:20 Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven.
Even jesus downplayed this example, which is very odd if it were to be doctrine. Once again the disciples mention devils and jesus says spirits.
Now we will have people who say "oh i've seen demons cast out of people". And to this i say "where, Haiti? Louisiana? Africa?. Wherever you see demons in effect you always have a people under "strong delusion". People who are possessed by demons have a belief that demons exist, people who don't believe it, are never possessed. Experience will point this out.
So, someone can be crying and disturbed and i can say "God loves you and he wants the best for you". and presto! they feel better. miraculous! no. plain and simple fact.