About Grays Harbor Comprehensive Treatment Center in Aberdeen, WA Grays Harbor Comprehensive Treatment Center provides medication-assisted treatment (MAT) to adults who are struggling with opioid addiction. Our center in Aberdeen, Washington, serves adults age 18 and older of all genders. MAT is an evidence-based approach to opioid addiction treatment that incorporates prescription medication and counseling. When MAT was first offered in the United States, methadone clinics were limited to one type of medication to help patients end their opioid use without experiencing painful withdrawal symptoms. Today, approved MAT providers such as our Aberdeen center can offer multiple medication options.