Eligibility Criteria

Inclusion Criteria:

- Men or women with a diagnosis of schizophrenia or schizoaffective disorder as defined
by DSM- IV criteria.

- Age between 18 and 65. Special attention will be placed on selective enrolling of
patients 18-25 to assess that they have been exposed to adequate medication trials
(minimum two medications) for sufficient length of time.

- During the 3 months prior to study entry, the patient must not have been an inpatient
in a hospital for longer than 4 weeks (cumulative hospitalizations) due to worsening
of psychiatric illness (although could have been participating in an inpatient
research protocol).

- Patients able to comprehend and satisfactorily comply with the protocol requirements;

- Patients with a PANSS total score of 60 or higher and a score of 4 (moderate) or
higher on two or more of the following PANSS items: delusions, hallucinatory
behavior, conceptual disorganization or suspiciousness.

- CGI scale rating of at least mildly ill, but not greater than severely ill.

- For women only: The patient must be non-pregnant, non-lactating, or has undergone
tubal ligation, bilateral oophorectomy or hysterectomy; or the patient must be at
least one year post menopausal; or the patient a) has negative urine or serum
pregnancy test (Beta HCG) and b) agrees to reliably practice contraception throughout
the study.

Exclusion Criteria:

- Primary psychiatric diagnosis other than schizophrenia or schizoaffective disorder.

- Patients who have had psychosurgery

- Recent (< 3 weeks) change in antipsychotic regimen

- Presence of clinically significant somatic disease that requires frequent changes in
medications or that could be aggravated by taking riluzole (i.e. severe liver
illness)

- Currently receiving treatment with potentially hepatotoxic drugs (e.g. allopurinol,
methyldopa, sulfasalazine)

- HIV positive, as assessed by blood testing (in part to avoid subjects with possible
brain HIV infection and to avoid rare complications of rarely occurring riluzole
induced neutropenia)

- Patients who pose immediate or significant enough risk for suicide or harm for others
as assessed by the study MD.

- Pregnant or nursing women, or women of childbearing potential who do not use adequate
contraception or who are judged to be unreliable in their use of contraception
(because there is not enough experience with riluzole use in nursing or pregnant
women)