Quetiapine to Reduce Post Concussive Syndrome After Mild Traumatic Brain Injury (mTBI)

Inclusion Criteria:

1. Male or female veterans seeking treatment for mTBI, aged 18-65 years

2. Meet mTBI diagnosis and have PCS symptoms reported on the Neurobehavioral SymptomInventory (NSI). Six months or more must elapse between the injury and Screening.mTBI diagnosis will be determined using the provisional diagnostic conventionrecommended by the VA/DoD requiring loss of consciousness, or a period of alteredconsciousness, or posttraumatic amnesia;

3. Be stable (i.e., no dose changes for > 1 month) on at least three CNS activepsychotropic medications prescribed for symptom relief or psychiatric treatment.

4. Have posttraumatic symptoms measured by PTSD Checklist for DSM-5 (PCL-5) score ≥25.

Exclusion Criteria:

1. Moderate or severe TBI, or major neurocognitive disorder (dementia).

2. Meet DSM-5 criteria for schizophrenia, bipolar disorder, schizoaffective disorder,or requiring inpatient hospitalization currently or within past 6 months.

3. Currently taking any antipsychotics or prohibited medication within the past month .

4. Known intolerance to quetiapine or a history of clinically unstable heart, lung,liver, renal, hematological, or endocrinological condition, diabetes mellitus,severe sleep apnea and/or seizure disorder.

5. Substance use disorder severe enough to require medication treatment or medicaldetoxification or inpatient hospitalization within 6 months of screening.

6. Reporting suicidal ideation of type 4 or 5 in the Columbia Suicide Severity RatingScale (CSSRS) in the past 3 months prior to screening or at screening or baselinevisit (i.e. active suicidal thought with method and intent but without specificplan, or active suicidal thought with method, intent, and plan); or homicidalideation with intent or plan to harm others within 90 days or suicide attempt; orsuicidal behavior within 6 months prior to screening.

(Note: Study psychiatrist will be immediately notified when SI or HI intent ispositive)

7. Current or known history of cardiac arrhythmia or QTc interval ≥ 470 milliseconds.

8. Pregnant or lactating women and those of child-bearing potential not using areliable method of contraception will be excluded from participating in the study.