Differences in Service Use Between Schizophrenic and Schizoaffective Patients

Kathryn Foxhall

May 08, 2008

May 8, 2008 (Washington, DC) — There are large differences in use of services, as well as medications, between patients with schizoaffective disorder and schizophrenia, according to researchers who looked at the Medicaid claims of more than 55,000 patients diagnosed with the disorders in 2 states over 6 months. The total combined Medicaid enrollment of the two states was about 9 million in 2005.

The gap is so significant that it may justify clinically distinguishing between the 2 disorders, argue the authors, from Ortho-McNeil Janssen Scientific Affairs. In addition, the 2 disorders place "distinctive demands on the mental health system."

The data showed differences, for example, in the use of psychotherapy, emergency room visits, and inpatient care between patients with these conditions.

The study was presented here at the American Psychiatric Association 161st Annual Meeting.

Important Differences

Coauthor George Wan, PhD, said the researchers were not disclosing which 2 states were in the study for contractual reasons. It Is important to examine the differences, the authors write, because there is much uncertainty around the diagnostic stability and interrater reliability of diagnosis for schizoaffective disorder, "a heterogeneous clinical condition encompassing psychotic, depressive, and manic symptoms.

"To our knowledge, few well-defined clinical principles exist to guide the treatment of schizoaffective disorder," say the authors. Further, little is known about the pharmacologic management patterns of outpatients with the problem, they write.

Of the people in the Medicaid populations with 1 of the 2 diagnoses, schizophrenia was more common, with 38,780, or 70.1%, treated for schizophrenia, compared with 16,570 or 29.9%, treated for schizoaffective disorder.

The data showed that in the prestudy period, significantly more schizoaffective patients were treated for substance use, anxiety, depressive disorders, bipolar disorders, and other mental disorders. The gap was largest for bipolar disorders, for which 14.8% of the schizoaffective population had treatment, vs 5.8% of the schizophrenia patients (P < .0001).


The percentages of the 2 groups that received antipsychotics were almost identical for both schizoaffective disorders and schizophrenia. However, schizoaffective patients were significantly more likely to receive antidepressants, mood stabilizers, and anxiolytics (P < .0001 for all comparisons).


Drug Treatment for Schizophrenia vs Schizoaffective Disorder

Drug Class Schizophrenia (%) Schizoaffective Disorder (%)
Antipsychotics 87.1 87.3
Antidepressants 44.0 61.6
Mood stabilizers 34.4 55.2
Anxiolytics 35.1 43.2

Schizoaffective patients were significantly more likely than schizophrenia patients to receive psychotherapy and to receive inpatient mental healthcare than those with schizophrenia. On the other hand, fewer patients with schizoaffective disorder had emergency-room visits than those with schizophrenia.

Service Use by Diagnosis

Service Schizophrenia (%) Schizoaffective Disorder (%)
Psychotherapy 13.0 23.4
Emergency room visits 8.2 5.8
Inpatient care 6.2 9.4

Dr. Wan, who is senior director for outcomes research for the company, emphasized to Medscape Psychiatry that when the researchers did logistic regression adjusting for age, sex, race, ethnicity, and mental health comorbidities, "we still showed a strong trend, in that the schizoaffective-disorder patients . . . were twice as likely to receive psychotherapy, as well as mood stabilizers and anxiolytic therapy."

After a negative binomial regression model was done, however, the 2 groups showed similar levels of mental health outpatient visits and general medical outpatient visits. But schizoaffective-disorder patients were less likely to have a mental health emergency-department visit (OR = 0.53) or mental health inpatient admission (OR = 0.88) as patients with schizophrenia.


The study also found some demographic differences between the 2 groups. More of the schizophrenia patients were male, and there were differences in the ethnic distribution. However, the mean age was about 43 years for both groups, and the distribution across age groups did not vary greatly.


Demographics for Schizophrenic vs Schizoaffective-Disorder Patients

Factor Schizophrenia Schizoaffective Disorder
Mean age (y) 43.2 42.5
Male (%) 64.2 46.7
White (%) 43.1 49.6
African American (%) 23.1 19.0
Hispanic (%) 9.2 12.3

The authors noted that limitations of the study include the fact that patients with extensive inpatient treatment during the prestudy period were excluded. In addition, they state, "Detection bias might contribute to the association between psychotherapy and schizoaffective disorder, as provision of psychotherapy offers opportunities for clinicians to detect mood symptoms required for schizoaffective-disorder diagnosis."

The authors conclude that schizoaffective disorder is commonly diagnosed among these Medicaid beneficiaries. "These patients often receive complex pharmacologic regimens," they write, and many also receive treatment for mood disorders. "Substantial differences in service use patterns between schizoaffective disorder and schizophrenia argue for considering separately the healthcare needs of these 2 patient groups."


American Psychiatric Association 161st Annual Meeting: Abstract NR4-067. Presented May 6, 2008.


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