Table 3 Likelihood of undergoing a head/brain MRI or CT scan: logistic regression results*

Antipsychotic categories vs other typicals (excluded category):

Risperidone (yes = 1)

0.812

0.770 to 0.855

< 0.0001

Clozapine (yes = 1)

0.976

0.853 to 1.116

0.7222

Olanzapine (yes = 1)

0.778

0.738 to 0.821

< 0.0001

Quetiapine (yes = 1)

0.901

0.851 to 0.954

0.0003

Ziprasidone (yes = 1)

0.828

0.750 to 0.913

0.0002

Haloperidol (yes = 1)

0.768

0.713 to 0.826

< 0.0001

Perphenazine (yes = 1)

0.709

0.626 to 0.803

< 0.0001

Hyperprolactinemia (inclusive of closely-related conditions*) during treatment (yes = 1)

1.781

1.354 to 2.343

< 0.0001

Interaction of antipsychotic and hyperprolactinemia:

Risperidone × hyperprolactinemia

1.658

1.232 to 2.232

0.0009

Clozapine × hyperprolactinemia

0.572

0.243 to 1.343

0.1993

Olanzapine × hyperprolactinemia

0.974

0.701 to 1.352

0.8748

Quetiapine × hyperprolactinemia

1.261

0.912 to 1.744

0.1613

Ziprasidone × hyperprolactinemia

1.663

1.057 to 2.615

0.0278

Haloperidol × hyperprolactinemia

1.157

0.741 to 1.805

0.5213

Perphenazine × hyperprolactinemia

1.237

0.568 to 2.696

0.5925

Duration of antipsychotic treatment episode, months

1.034

1.032 to 1.035

< 0.0001

Censored treatment episode (yes = 1)

0.746

0.723 to 0.770

< 0.0001

Age

1.018

1.017 to 1.018

< 0.0001

Male gender (yes = 1)

0.965

0.936 to 0.995

0.0217

Skull or brain injury 6 months prior to or during treatment (yes = 1)

4.956

4.672 to 5.258

< 0.0001

Skull neoplasm 6 months prior to or during treatment (yes = 1)

2.097

1.842 to 2.388

< 0.0001

Brain neoplasm 6 months prior to or during treatment (yes = 1)

8.630

7.687 to 9.689

< 0.0001

Used another antipsychotic within 6 months prior to treatment (yes = 1)

0.944

0.913 to 0.975

0.0005

Concurrent use of other atypical antipsychotic, ratio of days supply to index antipsychotic days supply

1.120

1.068 to 1.174

< 0.0001

Concurrent use of other typical antipsychotic, ratio of days supply to index antipsychotic days supply

1.145

1.075 to 1.220

< 0.0001

Diagnosis:

Schizophrenia (yes = 1)

1.023

0.989 to 1.057

0.1845

Affective psychoses (yes = 1)

1.429

1.386 to 1.474

< 0.0001

Other psychoses (yes = 1)

2.110

2.047 to 2.174

< 0.0001

Other non-psychotic mental disorders (yes = 1)

1.822

1.758 to 1.888

< 0.0001

Health coverage vs fee for service (excluded category):

Medicaid (yes = 1)

1.476

1.406 to 1.550

< 0.0001

HMO (yes = 1)

1.084

1.024 to 1.148

0.0053