Hello, Going by the history provided by you, it is quite possible that your husband has developed a dependence for methadone which is an addictive drug. Long term usage of it and sudden withdrawal can lead to withdrawal symptoms like insomnia (sleeplessness), irritability and hallucinations to name a few. The best way to deal with it is to recover in a hospital under the guidance of medical specialists to overcome such withdrawl symptoms. Therefore you need to consult a physician regarding the rehabilitation. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Riyanka Chail, General & Family Physician