Drug rehabilitation aims to break this cycle of dependency; this is done with psychotherapy, support groups and even other psychoactive substances: Acamprosate or naltrexone are examples of substances used to treat alcoholism, methadone or buprenorphine maintenance therapy in the case of opioid dependency. However, the reverse is also true in some cases, that is certain experiences on drugs may be so unfriendly and uncomforting that the user may never want to try the substance again. This is especially true of the deliriants (e.g. "datura") and dissociatives (e.g. "salvia divinorum").