A Study to Evaluate The Effects of RO5545965 in Participants With Negative Symptoms of Schizophrenia Treated With Antipsychotics

Inclusion Criteria:

- A diagnostic and statistical manual of mental disorders-5 (DSM-5) diagnosis of
schizophrenia as established by structured clinical interview for DSM-5-clinical
trial (SCID-5-CT) at screening

- Participants with no hospitalization for worsening of schizophrenia within 3 months
prior to screening

- Male and female participants with no childbearing capacity; females must be either
surgically sterile or postmenopausal for at least 1 year

- Body mass index (BMI) greater than (>) 18.5 kilograms per square meter (kg/m^2) and
less than (<) 35 kg/m^2

- Fluent in English, even if English is not the primary language

- Participants with clinical global impression-severity (CGI-S) score greater than or
equal to (>/=) 3 (mildly ill)

- Participants with a score of less than or equal to ( negative syndrome scale (PANSS) items P7 (hostility), G8 (uncooperativeness) and G6
(depression)

- Participants with PANSS negative symptom factor score >/=18

- Participants with calgary depression rating scale for schizophrenia (CDSS) score
- Participants on stable treatment, that is 6 weeks without change, with no more than
two antipsychotics prior to screening

Exclusion Criteria:

- Moderate to severe substance use disorder within 6 months as defined by DSM-5

- Positive urine drug screen for amphetamines, methamphetamines, opiates,
buprenorphine, methadone, cannabinoids, cocaine and barbiturates

- Participants at significant risk of suicide or harming him or herself or others
according to the Investigator's judgment

- History of neuroleptic malignant syndrome

- A prior or current general medical condition that might be impairing cognition or
other psychiatric functioning

- A movement disorder due to antipsychotic treatment not currently controlled with
anti-extrapyramidal symptoms (anti-EPS) treatment or another movement disorder which
might affect the ratings on the EPS scales

- Participants with a score >2 (mild) in any of the four CGI-S items of the
extrapyramidal symptom rating scale (ESRS-A)

- History of human immunodeficiency virus (HIV) infection, Hepatitis B, or Hepatitis C
infection

- QTcF interval >450 milliseconds (msec) (470 msec for females) or other significant
abnormality on screening electrocardiogram (ECG) based on centralized reading

- Clinically significant abnormalities in laboratory safety test results

- Significant or unstable physical condition

- Receipt of an investigational drug within 90 days or 5 times the half-life of the
investigational drug, whatever is longer, prior to screening

- Previously received RO5545965

- Electroconvulsive treatment (ECT) within 6 months prior to screening

- Current or 6 months prior to screening treatment with olanzapine or clozapine

- Change in benzodiazepine or sleep medication regimen within 2 weeks prior to
screening

- Change in anti-EPS medication within two weeks prior to screening

- Use of prohibited medications taken within 14 days or within 5 times the elimination
half-life of the medication before the first study drug administration

- Use of any strong or moderate inhibitor of cytochrome P 450 3A (CYP3A) or CYP2C8 and
any inducer of CYP3A within 14 days or within 5 times the elimination half-life of
the medication (whichever is longer) before the first study drug administration

- Use of any other nutrients known to modulate CYP3A activity within 1 week before the
first study drug administration