This open label study will evaluate the safety and efficacy of riluzole in patients with PTSD. Patients will receive riluzole 50mg twice per day orally for 12 weeks as outpatient, with a one month follow up at week 16.

Inclusion Criteria:

• Male or female subjects between the ages of 18-75 years;
• Able to provide written informed consent;
• Current Post Traumatic Stress Disorder, as determined by the Clinician Administered Scale for PTSD, or the presence of sub-threshold PTSD. Individuals with sub-threshold PTSD will be included at the discretion of the PI;
• Clinician Administered PTSD Scale (CAPS) score of 23 or higher;
• Be able to understand and speak English.
• Subjects taking FDA-approved antidepressant medications may enter the study if they have been on a stable dose for at least 4 weeks prior to starting the study drug.

Exclusion Criteria:

• Breastfeeding women and pregnant women, or women of child bearing potential who are not using a medically accepted means of contraception (to include oral, injectable, or implant birth control, condom, diaphragm with spermicide, intrauterine device, tubal ligation, abstinence, or partner with vasectomy);
• Current, ongoing serious suicidal risk as assessed by evaluating investigator or by scoring 5 or more on the item-10 of the MADRS.
• Unstable medical illness as determined by the investigator;
• Patients with schizophrenia or schizoaffective disorders (current or past);
• Substance use disorder during the 3 months prior to screening; except for Cannabis and Alcohol use Disorders.
• Clinical evidence of untreated hypothyroidism;
• Patients with any evidence of clinically significant liver abnormalities, or any liver transaminase level > 1.5 x ULN at initial screening, or > 5 x ULN during treatment;
• Axis II personality disorders that are the primary purpose of treatment, or would interfere with a patient's safety or compliance, as determined by the investigator during open-ended psychiatric interview;
• Patients currently being treated for a respiratory disorder (including asthma or COPD);
• For participants over the age of 60, evidence of dementia as determined by the St. Luis University Mental Status Exam (SLUMS; participants with total scores less than or equal to 20 will be excluded and referred to their Primary Care Physician for follow-up/dementia evaluation); Structured psychotherapy focused on treatment of PTSD is exclusionary unless the subject has had at least 8 weeks of treatment prior to starting the study medication;

18 participants started the study and 9 participants were randomized into the single arm of the study. However, only 8 participants completed the treatment. Since there was some treatment data collected on the 9th participant, he/she was included in the analysis.

8 weeks

The reporting of the adverse events reflects that one participant could have experienced more than one adverse event. For example, one participant experienced both dry mouth and lightheadedness. Similarly, three participants could have experienced chest pain. Thus, it may seem like the number of participants that experienced various adverse events does not match up to the number of participants in the participant flow. We analyzed 9 participants total and recorded their AEs in this section.