An Investigation of Early Life Stress and Depression

Primary outcomes

1. Dopamine Active Transporter Binding Potential

   Time frame: 1 hour PET scan (Session 3)

   Utilizing 11C-altropane during positron emission tomography (PET) scanning allows us to measure dopamine active transporter (DAT) binding potential.

   Our outcome measure is Nondisplacable Binding Potential (BPND). BPND refers to the ratio at equilibrium of specifically bound radioligand to that of nondisplaceable radioligand in tissue.

   *Higher BPND scores indicate greater binding potential

2. The Effects of CSA and Diagnosis on PRT Performance Under Acute Stress

   Time frame: 3 hour EEG Session (Session 4)

   The participant's performance on the Probabilistic Reward Task (PRT) was assessed both before and after an acute stressor. The PRT is a behavioral task that measures an individual's ability to learn from rewarding stimuli and incorporate this learning into their response style (response bias). The acute stressor was the Maastricht Acute Stress Test (MAST). The score obtained is a ratio of the number of times participants correctly choose the high reward stimuli versus the low rewarding stimuli. Response bias scores range between -1 and +1. Higher response bias scores indicate a stronger response bias toward high reward stimuli. A negative response bias indicates a stronger bias toward low reward stimuli.

3. The Effect of Major Depressive Disorder and Childhood Abuse History on a Reward-related EEG Component (Reward Positivity Component) While Under Stress

   Time frame: 3 hour EEG Session (Session 4)

   EEG was recorded during the probabilistic reward task (the PRT task). Participants completed the Probabilistic Reward Task (PRT) twice throughout the experiment, once before stress and once after stress. The stressor was the Maastricht Acute Stress Test (MAST). This statistic shows the effect that childhood sexual abuse (CSA) and diagnosis had on a reward-related positivity EEG component recorded during the PRT, before and after stress.

   • Higher reward positivity amplitudes indicate a stronger neural response to reward and lower amplitudes indicate a lower neural response to rewards.

4. Cortisol Output in Response to a Stress Manipulation

   Time frame: 3 hour EEG Session (Session 4)

   This statistic shows the impact of the stress manipulation on the participant's salivary cortisol output. Saliva samples were collected at 5 distinct time points throughout the study session. The first saliva sample (Cort 1) was collected when the participant began the eeg session. The second (Cort 2)was taken at the end of the acute stressor. The third (Cort 3) was taken approximately fifteen minutes after the second. The fourth (Cort 4) was taken approximately ten minutes after the third. The fifth (Cort 5) was taken approximately 40 minutes after the fourth.

5. Effects on Major Depressive Disorder and Childhood Sexual Abuse History on Striatal Activity in Response to Neutral and Reward Cues

   Time frame: 3 hour Drug & fMRI Session (Session 2)

   This statistic shows the influence of major depressive disorder and childhood sexual abuse history on the strength of striatal activation (caudate, putamen, accumbens) in response to neutral and reward cues during the monetary incentive delay task (MID).

   Striatal activation is measured using a statistic called a beta weight. A beta weight is a standardized regression coefficient. Higher beta weights mean greater striatal activation and lower beta weights mean less striatal activation. A negative beta weight would indicate a deactivation.

6. Effects on Major Depressive Disorder and Childhood Sexual Abuse History on Striatal Activity in Response to Neutral and Reward Feedback

   Time frame: 3 hour Session 2 (fMRI session)

   This statistic shows the influence of major depressive disorder and childhood sexual abuse history on the strength of striatal activation (caudate, putamen, accumbens) in response to neutral and reward feedback during the monetary incentive delay task (MID).

   Striatal activation is measured using a statistic called a beta weight. A beta weight is a standardized regression coefficient. Higher beta weights mean greater striatal activation and lower beta weights mean less striatal activation. A negative beta weight would indicate a deactivation.

7. The Effect of Diagnosis on Cortisol Reactivity

   Time frame: 3 hour EEG Session (Session 4)

   This is a measure of area under the curve in relation to ground, a measure of total cortisol output, in response to acute stress. The acute stressor was the Maastricht Acute Stress Test (MAST). The area under the curve includes all 5 cortisol measures, with one measure before the stressor and the other four measures collected after the stressor. Given that the cortisol data were positively skewed, the cortisol measures were normalized via a log transformation prior to calculating the area under the curve.

   Area under the curve with respect to ground (AUCG) is calculated AUC_g=(((cort2_log + cort1_log) * cort_t1_time) / 2)+(((cort3_log+cort2_log)*cort_t2_time)/2)+(((cort4_log+cort3_log)*cort_t3_time)/2)+(((cort5_log+cort4_log)*cort_t4_time)/2). Cort_logs are the log transformed cortisol output data (ng/ml) and the cort_times are the time spans in between each cortisol assessment.