Posttraumatic Stress Disorder
Conditions
Keywords
fMRI, stress, peptide, social, neuroimaging
Brief summary
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.
Detailed description
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.
Interventions
None listed
Sponsors
National Institute of Mental Health (NIMH)
Mclean Hospital
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Group differences in neuroeconomic game performance | Measured on the day of the MRI scan | Compared to the PTS-nonSA and HC groups, the PTS-SA group will demonstrate lower investments and slower learning rates on the Trust Task than on the non-social risk task compared with PTS-nonSA and HC subjects |
| Group differences in fMRI BOLD signal | Measured on the day of the MRI scan | The HC and PTS-nonSA groups will show greater ventral striatum (VS), dorsal striatum (DS), and medial prefrontal cortex (mPFC) responses during the outcome phase of the trust game for 'share' versus baseline, compared to the PTS-SA group, for the real partner condition (Trust Task), but not for the risk task. |
| Correlations between behavior and fMRI BOLD signal | Measured on the day of the MRI scan | Because social withdrawal will occur in response to reduced social reward value, we hypothesize that across the PTS groups, reduced VS, DS, and mPFC activity during the outcome phase of the trust game for 'share' outcomes will be associated with lower Trust Task investments, greater self-reported social anhedonia, and smaller social network size. |
| PACAP correlations | Measured on the day of the MRI scan | Elevated PACAP levels will be associated with lower investments on the Trust Task; decreased social reward signals during the outcome phase for 'share' outcomes in the VS, DS, and mPFC; and smaller social network size. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mediation analysis | Measured on the day of the MRI scan | Within the PTS groups, decreased VS, DS, and mPFC response to 'share' outcomes will mediate the relationship between social anhedonia and reduced social network size. |
| Functional connectivity (psychophysiological interaction) | Measured on the day of the MRI scan | PTS individuals with higher self-reported social anhedonia and social withdrawal will show reduced VS-mPFC connectivity for social rewards on the Trust Task. |
Countries
United States
Contacts
Primary ContactElizabeth Olson, PhD
Outcome results
None listed