The sensitivity of substance abuse treatment intensity to co-payment levels.

This study exploits variation in co-payment levels among different contractual arrangements within a regional managed behavioral health care organization to estimate the relationship between co-payment levels for substance use treatment services and the intensity of substance use treatment. The substance use treatment benefits involved a range of co-payment levels across nearly 400 employers during the years 1993 through 1998. Multiple regression techniques were used to estimate the effect of co-payment levels on treatment intensity. The results indicate that co-payment levels had a significant negative effect on outpatient and inpatient substance use treatment. For outpatient treatment the effect on intensity implied a co-payment elasticity of -0.18, implying that moving from a $10 co-payment to a $20 co-payment would result in, for example, a reduction from 5 to 4 outpatient visits per episode. However, the effect was larger for persons with combined alcohol and drug use disorders, as they exhibited a co-payment elasticity of -0.27. For inpatient days, the co-payment elasticity was considerably smaller at -0.017. Given the benefits of maintaining persons with substance use disorders in treatment, employers may have an incentive to take steps to minimize the barriers to treatment.