About Green Bay Comprehensive Treatment Center in Green Bay, WI Green Bay Comprehensive Treatment Center (CTC), located in Green Bay, Wisconsin, offers medication-assisted treatment (MAT) for adults age 18 and older of all genders who are struggling with opioid use disorder. MAT uses both prescription medication and counseling to help people achieve successful, lasting recovery from opioid addiction. Research has shown that MAT is a scientifically viable way to end opioid use that allows patients to avoid the painful withdrawal symptoms and severe cravings that would otherwise occur.