Characterizing the Neural Substrates of Irritability in Women: an Experimental Neuroendocrine Model
Characterizing the Neural Substrates of Irritability in Women: an Experimental Neuroendocrine Model
The proposed study involves experimentally manipulating reproductive hormones in nonpregnant, euthymic women to create a scaled down version of the changes that occur during pregnancy and the postpartum period. This endocrine manipulation paradigm, which the investigators have shown provokes irritability in past studies, will be used to examine the neurocircuitry underlying irritability under baseline and hormone challenge conditions among women who are hormone sensitive (HS+; n=15) and non-hormone sensitive (HS-; n=15). The long-term goal of this research is to advance understanding of the neural systems underlying both the triggering of and susceptibility to irritability in women. The objective of the current project is to examine whether HS+ show differences in the behavioral activation system relative to HS- under baseline and hormone challenge conditions using functional magnetic resonance imaging (fMRI) and behavioral tests.
Irritability, defined as a predisposition to exhibit anger, is a prominent, defining symptom of perinatal depression (PND) and many other neuropsychiatric disorders. Despite the near ubiquity of irritability across disorders, the neural dysfunction underlying the vulnerability to, onset of, and exacerbation of irritability is understudied and poorly understood. The proposed study involves experimentally manipulating reproductive hormones in nonpregnant, euthymic women to create a scaled down version of the changes that occur during pregnancy and the postpartum period. This endocrine manipulation paradigm, which the investigators have shown provokes irritability in past studies, will be used to examine the neurocircuitry underlying irritability under baseline and hormone challenge conditions among women who are hormone sensitive (HS+; n=15) and non-hormone sensitive (HS-; n=15). The long-term goal of this research is to advance understanding of the neural systems underlying both the triggering of and susceptibility to irritability in women. The objective of the current project is to examine whether HS+ show differences in the behavioral activation system relative to HS- under baseline and hormone challenge conditions using functional magnetic resonance imaging (fMRI) and behavioral tests. The investigator's central hypothesis is that reproductive hormone changes are associated with dysregulated threat and reward processing and consequent irritability in HS+. The rationale for the proposed study is that employing a scaled down model of puerperal hormonal events permits the identification of a group of individuals homogeneous for hormone sensitivity (HS+), hence creating the best opportunity for disentangling the specific changes in brain function due to reproductive hormones (i.e., HS-) from those accompanying reproductive hormone-precipitated affective dysfunction (i.e., HS+). Because women will act as their own controls across time, this study design also allows for a powerful evaluation of state and trait variables that may contribute to irritability, including both threat and reward processing. Identifying both state and trait markers of irritability, and disentangling them from the effects of reproductive hormones on brain and behavior, will allow for the identification of neural substrates of irritability susceptibility that can be investigated across neuropsychiatric disorders. The expected outcome of this research is the identification of neural circuits underlying both the susceptibility to and mediation of irritability.
Inclusion Criteria:
Participants will include healthy, euthymic 22-45 year old women with a history of postpartum depression (n=15) and women without such a history (n=15). Thus, only participants capable of giving informed consent will be enrolled. Participants will be compensated upon completion of the study.
Inclusion Criteria. Group 1: Women with a history of perinatal depression
Group 2: Healthy Controls
A structured clinical interview for DSM-V (SCID) will be administered to all women prior to study entry. Any woman with a current axis I psychiatric diagnosis will be excluded from participating in this protocol.
Exclusion Criteria:
Patients will not be permitted to enter this protocol if they have important clinical or laboratory abnormalities including any of the following:
Any woman meeting the Stages of Reproductive Aging Workshop Criteria (STRAW) for perimenopause will be excluded from participation. Specifically, the investigators will exclude any woman with an elevated plasma follicle stimulating hormone (FSH) level (> 14 IU/L) and with menstrual cycle variability of > 7 days different from their normal cycle length.
Pregnant women will be excluded from participation (patients will be warned not to become pregnant during the study and will be advised to employ barrier contraceptive methods), and women who become pregnant (although unlikely because of the hormone manipulation) will be withdrawn. The use of leuprolide acetate is not recommended during pregnancy. Prior to treatment, a complete physical, including a serum β-human chorionic gonadotropin (HCG) test for pregnancy. Participants will be seen at the outpatient clinic on a regular biweekly basis. All participants will be required to use non-hormonal forms of birth control (e.g., barrier methods) to avoid pregnancy during this study. Participants will also undergo urine toxicology and pregnancy tests on the day of each of the two fMRI scans. If a woman becomes pregnant during the study, she will not complete the fMRI scan, and the hormone protocol will be discontinued.