Our results suggest that Oregon's parity law did not result in large changes in the likelihood of initiating behavioral health care. However, once the decision to initiate care was made, patients were more likely to choose masters-level behavioral health specialists and less likely to choose generalist physicians. Overall, parity in Oregon was associated with a slight increase (0.5% to 0.8%) in initiations with masters-level specialists, and relatively little change for generalist physicians, psychiatrists and psychologists. These results are similar to findings by Lindrooth and colleagues, who found that a large employer's efforts to increase access to mental health care was associated with an increase in the use of nonphysician specialty mental health providers.17
Our study also suggests that patients are sensitive to distance from provider. To the extent that distance serves as a proxy for “cost” or “access”, these results provide some indication of the ways that increased or decreased access to provider types may affect patient choice. For example, demand for psychiatrists appears to be relatively insensitive to distance. This may be attributable to the relatively small proportion of patients who initiate care with psychiatrists, or it could be that there is relatively little substitution from psychiatrists to other providers for patients with certain mental illnesses, such as schizophrenia, major depression, or bipolar disorder.
Our results suggest that the MHPAEA will be associated with an increase in the use of masters-level specialty mental health providers, and, furthermore, this change may be enhanced through greater access to these types of providers. Since the evidence to date suggests that these nonphysician mental health specialists may be the most cost-effective care providers,7–9
health plans and employers may encourage these choices, which may further increase their use.
Those worried about expenses associated with parity may be reassured that the legislation did not trigger a rush to higher priced providers (psychiatrists and clinical psychologists). Parity may have stimulated a substitution (albeit small) of masters level mental health specialists for primary care providers. Given concerns about current and-or looming shortages of primary care providers, this substitution may well be generally beneficial. These topics have not previously been addressed in studies examining impact of parity legislation.
The changes associated with parity are relatively small in magnitude. These impacts are in line with most studies of parity, which generally do not appear to drive large changes in expenditures or utilization.2,3,5,27,28
On the one hand, this is good news for parity advocates, since this pattern of evidence may have helped pave the way for the comprehensive MHPAEA. On the other hand, advocates who hoped that parity would lead to greater use of mental health treatment have not seen evidence of parity leading to large-scale changes in access or in the quality of care provided.29,30
Nonetheless, parity has been shown to demonstrate some benefits, even if it does not appear to lead to substantial increases in seeking care by patients with unmet needs. For example, a study of Medicare enrollees suggested that mental health parity substantially improved the use of clinically appropriate mental health services following a psychiatric hospitalization,31
while Barry and Busch found that parity laws reduce the financial burden on families of children with mental health conditions.32
Our study has several limitations. Our comparison group consisted of individuals in Oregon whose employers were self insured and thus not affected by Oregon's parity law. There is a risk that this choice did not adequately control for secular trends. The study is also limited by a lack of detailed zip code and distance data in the comparison group. However, it is reassuring that, upon weighting with the propensity score, individuals from the self insured plans generally had similar demographic characteristics. Furthermore, we did not have plan-by-plan information on the distributions of providers across years. It is possible that observed changes in access of masters-level specialists were driven in part by unobserved changes in access to available providers in either the self-insured plans or plans covered by parity.
This study is also limited in its analysis of two PPO plans in Oregon, which may not be representative of other commercial plans in Oregon or commercial plans throughout the United States. Certain aspects of Oregon's insurance market and health care delivery system may not be generalizable to other parts of the country. Oregon is generally considered to have a competitive insurance market with an adequate supply of psychologists, social workers, and counselors (of various disciplines), although psychiatrists are more difficult to access. In addition, our study does not shed light on the importance of quality. Patients, purchasers, and health plans may also be sensitive to reputation or providers who demonstrate the use of evidence-based practices.
In summary, the experience in Oregon suggests that parity, while infrequently associated with changes in access, utilization, or quality, may indeed affect provider choice, with patients more frequently seeking care from masters-level specialists and less frequently seeking care from general physicians. Patients appear to be particularly sensitive to distance travelled for masters-level specialists. Thus, the shift to these types of providers may be highly contingent on their accessibility. Given the widespread and broad-based nature of the MHPAEA and ACA, masters-level specialists may become particularly prominent providers of behavioral health care for a large group of patients in the near future.