About El Cajon Comprehensive Treatment Center in El Cajon, CA El Cajon Comprehensive Treatment Center (CTC) provides medication-assisted treatment (MAT) to people who are struggling with opioid addiction. Our center in El Cajon, California, integrates medications and counseling to treat opioid use disorder, which is the clinical term for opioid addiction. We serve adults age 18 and older of all genders. MAT is an evidence-based practice that has been used for decades in methadone clinics. Research has documented that it is a highly effective way to treat opioid addiction. It is supported by the Substance Abuse and Mental Health Services Administration (SAMHSA) and the National Institute on Drug Abuse (NIDA) for this purpose.