Medicaid programs could improve treatment for beneficiaries with co-occurring mental and substance use disorders by adopting a “no wrong door” approach to treatment, allowing Medicaid beneficiaries with co-occurring disorders to reach adequate care no matter where they enter the health care system, according to a recent study.

Patients with co-occurring mental and substance use disorders are one of the most difficult groups to treat in the mental health arena, according to Dr. Robin Clark, lead author of the study. According to Clark, patients with co-occurring mental and substance use disorders are at risk for other conditions, including HIV infection and hepatitis C infection. In addition, patients in this group are overrepresented among homeless populations and are more likely to be arrested than are patients with only mental disorders, he said.

The study was conducted by Center for Health Policy and Research at the University of Massachusetts Medical School and Psychiatric Research Center at Dartmouth Medical School.

Centers for Medicare and Medicaid Services’ (CMS) 1999 data on Medicaid programs in Arkansas, Colorado, Indiana, New Jersey and Washington enabled researchers to compare Medicaid beneficiaries with co-occurring disorders and those with either a mental health or substance use diagnosis to see where they were treated.

Researchers found that one in five beneficiaries treated in hospitals and emergency departments received no Medicaid-funded behavioral health treatment outside of these settings. In addition, beneficiaries with co-occurring disorders were three to six times more likely than those with a mental health diagnosis alone to be hospitalized for psychiatric treatment, researchers said.

According to Clark, brief emergency room visits are expensive and cannot substitute for ongoing treatment methods available in community settings, such as community mental health centers and physicians’ offices.

Mary Kahn, CMS spokeswoman, said in an e-mail that “communities may not be ready to treat complicated co-morbidities such as mental health and substance abuse in an outpatient setting.” She added that although community-based care is strongly supported by CMS, “inpatient care can sometimes still be the most appropriate setting for some patients.”

By offering stronger financial incentives for metal health providers to identify and treat Medicaid beneficiaries with co-occurring mental and substance use disorders, locating community treatment providers in hospital inpatient, hospital outpatient, and emergency department settings and developing time-limited treatment or motivational interventions in emergency rooms to help beneficiaries set short term goals, Medicaid programs could improve access to treatment for beneficiaries with co-occurring disorders, researchers said.