It takes about 4-8 weeks. There are many types of phantom hearing, mainly real phantom hearing and pseudophantom hearing, etc. Different types of phantom hearing take different time to treat because of different causes, different medications, different body types and different treatment methods. Therefore, there is no definite time to determine how long it will take to eliminate hallucinations. Hallucinations can be treated with antipsychotic drugs such as risperidone, quetiapine, olanzapine, and fenadine. It usually takes 4-8 weeks after the medication has been administered at a therapeutic dose for the symptoms of hallucinations to significantly decrease or disappear.