The purpose of this study is to determine whether Riluzole is effective in the augmentation treatment of post-traumatic stress disorder (PTSD) that is experienced by Active Duty military service members and Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) veterans who have not had symptom reduction after one or more kinds of medications or therapies.

Riluzole is a glutamatergic modulator that inhibits glutamate release and enhances AMPA trafficking and clearance of excessive synaptic glutamate resulting in neuroprotective properties. Riluzole is FDA-approved for the treatment of amyotrophic lateral sclerosis (ALS) and has been found to have antidepressant and anxiolytic properties in animals and in humans (Zarate et al., 2004). Posttraumatic stress disorder (PTSD) is a chronic and seriously debilitating anxiety disorder that develops following exposure to severe trauma, such as combat exposure. Structural magnetic resonance imaging has been used to measure the volume of crucial structures implicated in the pathophysiology of PTSD, with several morphometric studies confirming smaller hippocampal volume in PTSD patients. Current pharmacological treatment for PTSD, and particularly combat-related PTSD, is suboptimal. Drugs that alter neuronal survival pathways through reduction of glutamate activity may play a role in reversing the loss of neuronal integrity and possible focal atrophy in regions of the brain implicated in the pathophysiology of PTSD, potentially improving the symptoms of PTSD, as well as TBI. This study will evaluate the efficacy of acute riluzole treatment in active duty and Operation Iraqi Freedom (OIF), Operation Enduring Freedom (OEF), and Operation New Dawn (OND) veterans with PTSD, with or without mild TBI (mTBI), who are sub-optimally responsive to other medication treatments. A total of 158 active duty and OIF, OEF and OND veterans, aged 18 to 65 will be enrolled from WRNMMC and the Syracuse VA Medical Center to participate in this 8-week randomized, double- blind, placebo-controlled, parallel study. Patients who are suboptimal responders to their current psychotropic drugs will continue these at stable dosage for at least 2 weeks prior to randomization during the screening period. We hypothesize that those subjects with PTSD, with or without mTBI, who are only partially responsive to initial therapy and are subsequently randomized to augmentation therapy with Riluzole (100-200mg/day) will have a superior response rate compared to those subjects randomized to placebo.

Inclusion Criteria:

• Active-duty service member or an Operation Iraqi Freedom (OIF), Operation Enduring Freedom (OEF), or Operation New Dawn (OND) veteran.
• Clinical diagnosis of PTSD and have not achieved remission with an adequate trial of medication treatment (8 weeks) as indicated by self-report at referral and confirmed by baseline CAPS score of greater than or = to 40 after informed consent is obtained.

Exclusion Criteria:

1. Female subjects of childbearing capacity who test positively for ß-HCG, or are either self-reporting as pregnant, planning to become pregnant, or nursing.
2. Presence of psychotic features.
3. Unable to provide informed consent or comply with study procedures.
4. Previous treatment with riluzole.
5. Serious, unstable illnesses including hepatic, renal, gastroenterological, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, hematologic disease, or HIV. This includes individuals with a history of COPD by diagnosis as well as persons taking inhalers for Asthma or Reactive Airway Disease.
6. Clinically significant abnormal levels (3x ULN or greater) of serum transaminases (ALT/SGPT; AST/SGOT), current or past blood dyscrasia.
7. Subjects with uncorrected hypothyroidism or hyperthyroidism.
8. DSM-IV alcohol or substance abuse or dependence within 90 days of the screening visit.
9. Treatment with a reversible MAOI, guanethidine, or guanadrel within 1 week, or any change in fluoxetine dosing within 8 weeks prior to visit 2. Use of antidepressant and sedative/hypnotic drugs at stable dose is permitted.
10. Documented history of hypersensitivity or intolerance to riluzole.
11. Subjects with a current or past history of other axis I disorders including schizophrenia, schizoaffective disorder, bipolar disorder or dementia. However, those with a co-morbid history of other Axis I disorder like major depression, dysthymia or other anxiety disorders will be included; the justification for this is that approximately 70% of subjects with PTSD have co-morbid depression and or alcohol abuse, and restricting the sample to PTSD patients without depression will not accurately reflect the scope of this disorder.
12. Patients who are currently at high risk for homicide or suicide, as indicated by an affirmative answer to the question: "In the last three months, have you attempted to kill yourself, made specific plans to kill yourself, or had the intention to kill yourself?"
13. Current or planned litigation regarding the traumatic event.
14. Patients who recently started trauma focused cognitive behavioral psychotherapy (Patient's underlying educational or supportive individual or group therapy will be included).
15. Patient's actively enrolled in an evidence based psychotherapy treatment (e.g., Cognitive Processing Therapy or Prolonged Exposure Therapy) will be excluded until that therapy has concluded, but may be re-approached at that time if patient self-report or clinician referral suggests persistent PTSD symptoms upon conclusion of that treatment.
16. Subjects with an artificial cardiac pacemaker or metallic implants within their body will be enrolled at WRNMMC for the placebo-control clinical trial portion of the study only. These individuals, due to their pre-existing medical condition, are medically ineligible to participate in the 1H MRS imaging portion of the study. Further, the Magnetic Resonance (MRI) Screening Form is use at WRNMMC will be used for participant screening prior to any imaging procedures.
17. Use of benzodiazepines.

One participant failed to meet minimum Clinician-Administered PTSD Scale IV (CAPS-IV) score for inclusion at phase 2 baseline and was excluded from intent-to treat (ITT) analyses.

10 weeks

Result limited to combat-related PTSD in military and veterans of recent conflict.