They can cause both psychological and physiological withdrawal. Becomes an iatrogenic illness when you psychologically don't need or want the drug, but your body continues to crave it in order to function normally... assaulting you with horrendous symptoms; pins and needles, nausea, screaming joint pain, body aches, no sleep, etc... It is the receptors in the brain that have been damaged. They have to have time heal. That time frame varies from person to person. The only way out is through. Be strong, you can get through. ((Hugs))