Estrogen and Fear in PTSD

Prolonged-exposure (PE) therapy is the treatment of choice for posttraumatic stress disorder (PTSD). Despite its efficacy, a significant number of individuals will not benefit from it or might drop out before the completion of all sessions. This underlies the importance of findings ways to enhance the efficacy of PE in order to improve the life quality of individuals suffering from PTSD. It is now widely accepted that extinction learning paradigms used in fundamental studies are useful laboratory analogs to PE. Studies in healthy controls have suggested that elevated estrogen levels benefit extinction learning by promoting its consolidation and thus enhancing its recall when tested later for it. This is also being reflected by changes in the activation of brain regions forming the fear extinction network, including the amygdala, dorsal anterior cingulate cortex (dACC) and ventromedial prefrontal cortex (vmPFC). It is still unknown whether estradiol (E2) administration can modulate the activation of the fear extinction network in oral contraceptive (OC) users and which E2 dose could yield the best results. During the R61 phase of the study, we found that both doses of E2 were effective in engaging the functional activation of the fear extinction network. Therefore, we will use the lower dose (2mg) for the R33 phase. We will combine E2 administration with PE sessions to see if administration of PE can significantly improve clinical outcomes (reduced PTSD symptoms) and engage the fear extinction network in the brain.

Hypothesis: A general improvement is expected after 3 weeks of treatment in both groups given the anticipated benefits of PE alone. But the benefit of the Estradiol-treated groups is hypothesized be larger; with this group exhibiting significantly higher activation in brain regions associated with fear extinction. This will be noted at the follow-up scan compared to the baseline scan.

PTSD symptom severity expected be significantly lower in the Estradiol and PE group relative to the Placebo+PE group following acute treatment after three weeks of treatment.

The degree of PTSD symptom reduction post- compared to pre-PE after 3 weeks of treatment is expected be associated with BOLD changes in the fear extinction network and reduction in SCR during the extinction recall test after PE. The magnitude of BOLD and SCR changes will be significantly larger in the E2+PE group compared to the Plc+PE group.

Inclusion criteria

• Female, 18-45 years of age
• Chronic (at least one month post-trauma) DSM-5 FULL PTSD diagnosis OR subPTSD diagnosis (subPTSD defined as: meeting criterion A, F, G, H, and clusters B, C, and at least 1 of the clusters D or E.)
• CAPS-5 Past Month score ≥ 20
• Criterion A traumatic event
• Stable medications for 3 or more months by the time of study entrance (with the exception of benzodiazepines)
• Women on oral contraceptives, specifically those using monophasic or biphasic of first, second, third or fourth generation with up to 35mcg of ethinyl estradiol; OR using etonogestrel / ethinyl estradiol 0.120mg/0.015mg per day vaginal ring birth control; OR using the norelgestromin / ethinyl estradiol 0.150mg/0.035mg per day transdermal patch birth control.
• Willing and able to provide informed consent

Exclusion criteria

• Diagnosis of bipolar I disorder with a past year manic episode
• Diagnosis of a psychotic disorder or psychotic symptoms that would interfere with the ability to focus on posttraumatic stress disorder (PTSD) in clinic, as determined by clinical judgment.
• Diagnosis of moderate or severe substance use disorder that would interfere with the ability to focus on posttraumatic stress disorder (PTSD) in clinic, as determined by clinical judgment.
• Cognitive impairment that would interfere with the ability to focus on posttraumatic stress disorder (PTSD) in clinic, as determined by clinical judgment.
• History of neurological disease (that involves the brain), seizure, or significant head trauma (i.e., extended loss of consciousness, neurological sequelae, or known structural brain lesion).
• Suicidal ideation with imminent risk that warrants a higher level of care.
• Concurrent trauma focused psychotherapy
• Pregnancy (to be ruled out by urine ß-HCG).
• Metallic implants or devices contraindicating magnetic resonance imaging by interfering with patient safety or fMRI data collection. Cases will be cleared by the Principal Investigator and/or Baylor College of Medicine (Imaging).
• History of breast cancer or hormone-responsive cancer.
• Use of benzodiazepines
• Self-injurious behavior that involves suicidal intent, requires medical attention, or occurs daily.
• High risk of adverse emotional or behavioral reaction, and/or an inability to understand study procedures or the informed consent process, based on investigator/clinician clinical evaluation (e.g., evidence of serious personality disorder, antisocial behavior, serious current stressors, lack of meaningful social support)