Hallucinations are caused by spirits. To control those spirits you must control your mind.
Human beings are ruled by spirits but humans must learn to control and rule the spirits. Spirits possess people according to the mental state of the human beings and keep them in the same state until they are rejected and replaced by another. This is an all time phenomena occurring in all humans. Human beings are always under the influence of spirits. Certain situations and circumstances causes the possession of certain type of spirits. Often thinking and talking about bad subjects or bad imaginations even for fun can take serious turns on one who think and talk. Often thinking and talking about good subjects with good imaginations can create positive effects in your life. Your favorable thoughts and beliefs can bring favorable spirits by your side. The more you think the more would be the possession of that spirit. All spirits (good and bad) have the dominating character. They can take you to the extent of sacrifice or suicide.
All of your activities, talks and even thoughts determine what kind of spirits you will have for your life. Only these spirits are the reason for the good and bad happening in your life. Generally spirits determine your destiny from your daily activities, talks and thoughts too. Spirits are separate elements. A human being is not a single spirit. A human being doesn't have a spiritual body. A human being during his/her life time is living with many spirits which have joined one by one since birth. They are knowledge, skills, feelings, emotions, interests and everything. Even thoughts are not your own. For example, when you want to take a decision on a subject, one after another the spirits think and you just listen, choose or reject the ideas which they transmit to your mind through your brain in the form of thoughts. Brain is just a media to connect the spirits to your mind. A mind is just a computer's mind. After the destruction of a computer completely you will not get it's mind. The same is the case with the human beings. Soul is nothing but an energy needed for the functionality of a body. It is not a spirit or anything else. All human beings are just robots made of flesh and bones and toys of the spirits for their games.
You must not leave your mind in it's own way. If you do, the spirit will take your mind for it's own, then controlling it is not so easy. First of all you must think and believe that it's not you. Then you must command that spirit both mentally and orally to go. Whenever you are possessed by hallucinations you must divert your mind at once towards some other subject and stay in it for a while and then continue your duty. The more you listen the more would be the possession of the hallucinations. You must control your mind.