This study will use a neuroeconomic paradigm with state-of-the-art imaging protocols to probe abnormal social reward processing underlying social withdrawal in symptomatic trauma-exposed women. By also gathering self-report measures of social anhedonia, performance on non-social and social reward valuation tasks, and measures of real-world social functioning including social network size, we aim to specify how alterations in social reward processing result in social withdrawal and functional impairment.

Impaired social functioning is a frequent and disabling sequela of trauma-related disorders. PTSD is associated with a high rate of severe impairment in quality of life relative to other anxiety disorders, including panic disorder, social phobia, and OCD, with particularly marked impairment in social quality of life. Mounting evidence indicates that impairment in quality of life in PTSD is strongly related to its effect on social functioning. Such difficulties are widespread and affect multiple social networks, including marital relationships, and friendships and family relationships. Social withdrawal, defined here in terms of reduced social network size, is of particular interest because of its strong relationship with health outcomes, including increased risk of disability, reduced immune response, and increased mortality risk; most critically, poor social integration is associated with a threefold increase in suicide risk. Because women are at a 2.3-to-3-fold increased risk compared to men of developing PTSD following trauma, understanding the differential neurobiological pathways that may contribute to the development of stress-related disorders in women is particularly critical. Women are more likely than men to endorse social detachment following trauma, especially when the trauma involves exposure to violence.

In this project, we propose abnormal reward processing (anhedonia) as a specific mechanism underlying social withdrawal in trauma-exposed women, and we present a paradigm that capitalizes on advances in neuroeconomics to elucidate the neural underpinnings of social withdrawal. Additionally, we propose to identify the possible influences of a stress peptide (pituitary adenylate cyclase-activating polypeptide: PACAP) implicated in sex-specific changes in social behavior following stress exposure.

Phase 1:

Inclusion Criteria:

• Age 18-45
• Self-reported healthy volunteer status

Exclusion Criteria:

• Inability to provide written informed consent in English
• Inability to see task due to visual impairment
• Participants who produce T-scores of 65 or higher on any Brief Symptom Inventory (BSI) subscales will not be eligible to remain in the Trust Task participant pool.

Phase 2:

Inclusion Criteria:

• Female
• Trauma exposure appropriate to group
• For trauma-exposed groups the index trauma is actual or threatened physical assault or sexual violence
• PCL-5 score 33 and above (for PS-SA and PS-nonSA groups)
• Right handedness
• Age 18-45
• English as a first language

Exclusion Criteria:

• History of neurological illness (including head injury with loss of consciousness > 5 minutes)
• Medical conditions that may influence neuroimaging (e.g. HIV)
• Current or past DSM-5 Axis I disorder (for HC group)
• History of bipolar disorder or schizophrenia spectrum disorder
• Contraindications for MRI
• Alcohol dependence in the past 5 years
• Substance dependence in the past 3 years
• Daily substance use in the past year
• Prescribed psychotropic medication use in the past month
• Wechsler Abbreviated Scale of Intelligence- Second Edition (WASI-II) FSIQ < 70.

Phase 1 will include healthy volunteers (age 18-45, n = 60).

Phase 2 will include posttraumatic spectrum-socially anhedonic women (PTS-SA, n = 36), posttraumatic spectrum-non-socially anhedonic women (PTS-nonSA), and healthy controls (HC, n = 36).

We will evaluate requests for deidentified data on a case-by-case basis.