"Proposition 36 has successfully brought a large number of drug-abusing offenders to treatment in a very short time period, many for the first time.15,17 Although this is an important first step, positive therapeutic effects require clients’ engagement in appropriate treatment over a sufficient period of time,8 and positive outcomes depend on services that effectively address clients’ multiple needs.19–22 Treatment capacity expansion for Proposition 36 offenders was observed mostly in ODF [Outpatient Drug Free] programs, often with short planned durations, which may not be adequate for severe-level drug abusers, for heroin addicts, and particularly for clients with co-occurring mental disorders and other problems. Undertreatment (inadequate intensity and duration) has been found to be associated with high rates of recidivism.23 Although more direct evidence for displacement (e.g., longer wait time for non–Proposition 36 clients) should be sought, our findings suggest that displacement may be an unintended negative consequence of Proposition 36 that needs further investigation. Is the perceived or actual unavailability of treatment or inadequate level of available treatment for voluntary clients contributing to a lower rate of help seeking and, thus, to the ongoing public health and safety problems of untreated addiction? There has been some indication that policies promoting 'treatment on demand' have increased access only for some populations, but not for the indigent or for opiate addicts needing methadone maintenance.24 It has also been suggested that increased caseloads result in increased pressures on programs and staff, which undermine treatment objectives.25"

Source

Yih-Ing Hser, et al., "Impact of California's Proposition 36 on the Drug Treatment System: Treatment Capacity and Displacement," American Journal of Public Health, Jan. 2007, Vol. 97, No. 1.
https://www.ncbi.nlm.nih.gov/...
https://www.ncbi.nlm.nih.gov/...