A Study to Assess the Clinical Utility of Antipsychotic Medication Levels in Plasma as Determined by Liquid Chromatography-Tandem Mass Spectrometry

This is a naturalistic, open-label (all people know the identity of the intervention),
multicenter (when more than one hospital or medical school team work on a medical research
study), pilot clinical utility study with a sequential and parallel cohort design in
participants with a diagnosis of schizophrenia or schizoaffective disorder. The study
consists of up to 3 Phases: Screening Phase (Screening and first assessment visit should
preferably take place on the same day), active assessment phase (12 weeks, An optional 12
week extension phase. Participants will be assigned to Cohort 1, or randomized to Cohort 2
or Cohort 3. Participants in cohorts 2 and 3 who are receiving long acting injectable (LAI)
formulations of paliperidone and/or risperidone and complete participation in the active
assessment phase) will have the option of continuing into the extension phase. The duration
of study participation will be approximately 12 weeks. Participants in the optional
extension phase will have an additional 12 weeks of study participation. The primary outcome
will be measured by the number of Medication Treatment Modifications (MTMs) made by the
clinician at every visit. Participants' safety will be monitored throughout the study.

Inclusion Criteria:

- Participant has a diagnosis of schizophrenia (Code 295.90) or schizoaffective
disorder (Code 295.70) according to Diagnostic and Statistical Manual of Mental
Disorders, 5th edition (DSM 5), based on history and clinical assessment by the
investigator

- Participant has current active medication management issues and has experienced a
medication treatment modification within the 6 weeks prior to Screening

- Participant is currently taking one or more of the following antipsychotic
medications for at least 1 week for oral antipsychotics and at least 1 injection
cycle for long-acting injectable (LAI) antipsychotics. In addition, the treating
clinician plans to continue the antipsychotic medication(s) for at least 4 weeks
subsequent to the Screening visit. Participant may be taking more than one
formulation of a particular medication (such as oral and LAI) at or above the minimum
dose specified in protocol. Qualifying formulations of the antipsychotic medications
are: Aripiprazole (oral formulation only), Olanzapine (oral formulation only),
Paliperidone (oral and/or LAI formulations), Quetiapine (oral formulation only), and
Risperidone (oral and/or LAI formulations)

- Participant has had no clinically significant suicidal behavior or ideation during
the week prior to Screening, according to the investigator's judgment

- Participant is generally healthy and has no clinically significant or unstable
medical problems as determined by the investigator, except for the indication for
which the antipsychotic treatment is being prescribed. This determination must be
recorded in the participant's source documents and initialed by the investigator

Exclusion Criteria:

- Participant has been attending the outpatient psychiatric clinic for more than 12
months since the last psychiatric hospitalization

- During Screening, participant has active alcohol or substance use disorder (except
tobacco) of moderate or severe severity according to DSM 5 criteria

- Participant has a history of or currently has a clinically significant (particularly
unstable) medical illness, other than the indication for which the participant is
taking antipsychotic therapy, that the investigator considers should exclude the
participant or that could interfere with the participant completing the study or with
interpretation of the study results. Treated, stable, chronic medical problems are
allowed, as long as these conditions do not interfere with the study assessments

- Participant is receiving clozapine

- Participant has donated blood or blood products or had substantial loss of blood (ie,
blood loss of approximately more than 450 milliliter (mL) or blood loss that required
a blood transfusion) within 1 month of Screening or has the intention to donate blood
or blood products during the study