Why Clozapine Use Varies by State

Psychiatric TimesVol 33 No 3
Volume 33
Issue 3

Reasons for the overall low rate of clozapine use brings to light questionable decisions on the part of policymakers

TABLE. Clozapine use and number of psychiatrists by state

TABLE. Clozapine use and number of psychiatrists by state


In November of last year, Olfson and colleagues1 reported that clozapine use for individuals with schizophrenia continues to be very low in the US, compared with other Western countries. Equally concerning, however, was their finding that there is a 7-fold variation in clozapine use by state, from South Dakota, where 15.6% of Medicaid recipients with schizophrenia receive clozapine, to Louisiana, where only 2% receive clozapine. This report was subsequently enlarged using pharmacy data by the Treatment Advocacy Center.2

Many reasons have been put forth for the overall low rate of clozapine use, including the administrative complexity of the monitoring program, the low Medicaid reimbursement, and the role of pharmaceutical companies who promote their patented antipsychotics. However, I am not aware of any study that has attempted to ascertain the reasons for the 7-fold difference in clozapine use among the states.

What’s behind the discrepancy?

In my quest to understand the reasons for the differences, I found several factors that affect the numbers of prescriptions for clozapine. Because of its mandatory blood monitoring requirements, clozapine is usually prescribed by psychiatrists rather than by other medical practitioners. There is a more than 5-fold difference in the number of psychiatrists among states, which is reflected in the number of prescriptions for clozapine. For example, there are 3545 people per psychiatrist in Massachusetts and 18,997 people per psychiatrist in Idaho.2

I compared the rank order of the states by clozapine use with the rank order by people per psychiatrist and found that the association was only slightly positive (Spearman’s nonparametric; rho = 0.26) and not statistically significant. Thus, the distribution of psychiatrists in the US explained very little of the differences in clozapine use among the states.

Next I looked at the urban-rural differences. It is easier to monitor clozapine use in urban areas, where patients can get to clinics relatively easily, than in rural areas, where patients may have to travel great distances. As seen in the Table, however, many of the states with the highest use of clozapine, such as South Dakota, Vermont, North Dakota, Wyoming, and Montana, are among the most rural of all the states. Urbanicity clearly is not the answer.

[[{"type":"media","view_mode":"media_crop","fid":"46743","attributes":{"alt":"NORMAN POGSON/SHUTTERSTOCK.COM","class":"media-image media-image-right","height":"181","id":"media_crop_3150874403786","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5442","media_crop_rotate":"0","media_crop_scale_h":"217","media_crop_scale_w":"100","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"NORMAN POGSON/SHUTTERSTOCK.COM","typeof":"foaf:Image","width":"83"}}]]The next question that I examined was what organization has clinical responsibility for providing psychiatric care to each state’s Medicaid population. According to data from the Kaiser Family Foundation,3 34 states and the District of Columbia use for-profit managed care companies to manage medical care, including behavioral health, for at least some of the state’s Medicaid population. The other 16 states do not.

As seen in the Table, the states that do not use for-profit companies are disproportionately represented at the top of the list of clozapine use. In fact, 8 of the 16 states that do not use for-profit managed care are included among the 13 states with the highest clozapine use. When the average clozapine use rate for the 34 states using for-profit managed care (4.7%) is compared with the 16 states not using for-profit managed care (6.9%), there is a strong association between lower clozapine use and for-profit managed care, although the association does not achieve statistical significance (Wilcoxon rank sum test; P = .08). To examine this association in greater detail would require a detailed analysis on the use of managed care for each state for 2006 to 2009, the same years as the clozapine use data.

What do states that do not use for-profit companies for psychiatric care of Medicaid enrollees use (eg, South Dakota, which has the highest rate of clozapine use of any state)? According to Cory Nelson, who was the chief executive officer of the state’s single state hospital (Human Service Center) during the period when these data were collected, most individuals with acute or chronic episodes of schizophrenia were admitted to the state hospital for a brief (average, 12- to 15-day) stay. Nelson reported that the hospital had “a full staff of board-certified psychiatrists” who were all clinical faculty associated with the medical school (personal communication, November 12, 2015). Major efforts were directed toward finding the most effective antipsychotic for each patient and reducing the use of multiple antipsychotics. An active “medical director and PharmD did constant review of this issue and held regular ‘difficult case conferences’ whenever challenges arose.” The patients were then discharged to 11 nonprofit community mental health centers that were accredited and largely funded by the state.

In North Dakota, which also ranked comparatively high in the survey (8.9% of individuals with schizophrenia on Medicaid were taking clozapine), the situation is similar. The state has a single state hospital and also owns and operates 8 community mental health centers. According to Andy McLean, MD, the Medical Director for the Department of Human Services and Chair of the Department of Psychiatry at the medical school, “we have been very active in our CMHCs in utilizing clozapine as a best practice [and] are in the process of adding a dedicated clozapine clinic to our psychiatry residency program” (personal communication, November 10, 2015).

A more detailed examination of each state’s administration of responsibility for providing psychiatric care to its Medicaid population may explain other apparent discrepancies. Washington is the only state among the top 6 clozapine users that uses for-profit managed care for behavioral health. In fact, it does so in only a single county (Optum Health, affiliated with UnitedHealth Group, has a contract for Pierce County). All the other counties have Medicaid psychiatric services administered by county-based Regional Support Networks operating as prepaid health plans, which may explain the state’s high ranking on clozapine use despite using for-profit managed care in one county.

The Bottom Line

The fact that states using for-profit managed care companies have lower use of clozapine for individuals with schizophrenia on Medicaid raises additional questions. Since clozapine is administratively more expensive to use initially but has proved to save money in the long run by decreasing re-hospitalization rates, are the for-profit managed care companies only interested in short-term profits? And are for-profit managed care companies associated with other indicators of inferior psychiatric care? Since for-profit managed care is spreading rapidly, these questions need answers.


Dr Torrey is a research psychiatrist who specializes in schizophrenia and bipolar disorder. He is founder of the Treatment Advocacy Center and Associate Director of the Stanley Medical Research Institute, which supports research on schizophrenia and bipolar disorder, and he is Professor of Psychiatry at the Uniformed Services University of the Health Sciences in Bethesda, MD. He reports no conflicts of interest concerning the subject matter of this article.


1. Olfson M, Gerhard T, Crystal S, Stroup TS. Clozapine for schizophrenia: state variation in evidence-based practice. Psychiatr Serv. 2016;67:152. http://dx.doi.org/10.1176/appi.ps.201500324.

2. Torrey EF, Knable MB, Quanbeck C, Davis JM. Clozapine for treating schizophrenia: a comparison of the states. A report of the Treatment Advocacy Center. November 2015. http://www.tacreports.org/storage/documents/clozapine-for-treating-schizophrenia.pdf. Accessed February 9, 2016.

3. Kaiser Family Foundation. Medicaid managed care market tracker. http://kff.org/data-collection/medicaid-managed-care-market-tracker/. Accessed February 9, 2016.

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