appetitive conditioning: The investigators will examine acquisition and extinction of learned associations to positively-valenced, socially rewarding yet symptom-neutral infant laughter sounds in an appetitive conditioning paradigm. The investigators will also examine spontaneous recovery of this association 24 hours later when re-presented with these cues, and the reinstatement of this association when re-exposed to infant laughter.
Study summary
Anorexia nervosa (AN) is characterized by a reduced drive to pursue rewarding experiences and stimuli. Food consumption - which is almost universally experienced as pleasurable - is not described as rewarding by those with AN. This is thought to be underpinned by abnormalities around reward learning. However, the most fundamental question relating to reward in AN - whether those with AN may learn positive associations - remains unaddressed.
In this study, the investigators will identify the patterns of how those with AN acquire positive associations, how they diminish, and their relationships to physiology (heart rate and pupil responses) and brain activation. In assessing the robustness of this learning, the investigators will investigate the extent to which this association is reactivated after 24 hours, and the extent to which a memory prompt will help reinstate this previously learned positive association.
This project will allow for important advances in our understanding of the neurobiology of AN. The investigators will first identify if, and how, those with AN come to learn positive associations to cues, and secondly, the extent to which learned positive associations remain over time. Moreover, the investigators will use machine learning to ascertain whether reward learning can be predicted by physiological and neural biomarkers.
Eligibility
Sex
FEMALE
Min age
12 Years
Max age
22 Years
Healthy volunteers
Accepted
Inclusion Criteria:
1. AN-Restricting (AN-R) Group
Inclusion criteria:
1. Females from any racial or ethnic background
2. Ages between 12 and 22 years
3. Meet DSM-5 criteria for AN - restricting subtype
4. Medically stable designated by their physician in the past month (having any of the following measurements taken by a physician or nurse within the past month preceding the telephone screen: (i) orthostasis: drop in systolic blood pressure \> 20 mm Hg or diastolic blood pressure \> 10 mm Hg, or an increase in heart rate (HR) \> 20 bpm upon standing for 3 minutes after lying down; (ii) resting HR \<45; or (iii) resting blood pressure of \<80 mm Hg systolic or \<50 mm Hg diastolic 99. Prospective participants who do not meet the medical instability criteria and otherwise pass the telephone screen, will be invited to proceed to the consent process. If they have not had these measurements done in the month prior, we will encourage them to visit their doctor or nurse to have these done and then to recontact us with the results ):
5. BP and pulse measured at the day of the scan by the investigators
* Heart rate ≥ 45 at rest
* Resting blood pressure of ≥80 mm Hg systolic and ≥50 mm Hg diastolic
* Lying and standing (after 3 min.) BP drop of ≤20 systolic and ≤10 diastolic and increase in HR ≤20 bpm
6. Not taking psychiatric medications or taking serotonin-reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor medications at stable doses
2. History of AN-Restricting Group:
Inclusion criteria:
1. Females from any racial or ethnic background
2. Ages between 12 and 22 years
3. EDE-Q ≤ 2 (puts them within 1 standard deviation \[SD\] of community norms and lower than 1 SD from clinical norms for female AN-R)
4. History of AN - meeting full criteria, diagnosed by a licensed clinician
5. Not taking psychiatric medications or taking serotonin-reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor medications at stable doses
3. Healthy controls:
Inclusion criteria:
1. Healthy females from any racial or ethnic background
2. Ages 12-22 years
Exclusion Criteria:
* AN-R and History of AN-R groups:
1. Antipsychotic medications
2. Change in dose of psychotropic medication over the previous 4 weeks
3. Current psychotic disorder
Healthy controls:
1. Any current Axis I disorder
2. Eating Disorder Examination Questionnaire score greater than established community norms (\>2)
3. Met criteria for AN (in the past or present)
All:
1. Neurological disorder
2. Infants or children of their own
3. Pregnancy
4. Current risk of suicide with a plan and intent
5. Ferromagnetic metal implantations or devices (electronic implants or devices, infusion pumps, aneurysm clips, metal fragments or foreign bodies, metal prostheses, joints, rods or plates)
Primary outcome measure(s)
Positive valence — Day 1 A 10-point Likert scale will assess self-reported pleasantness and arousal for each conditioned stimulus, and unconditioned stimulus expectancy
Positive valence — Day 2 A 10-point Likert scale will assess self-reported pleasantness and arousal for each conditioned stimulus, and unconditioned stimulus expectancy
Pupillary dilation — Day 1 Measured with an eye-tracking camera
Pupillary dilation — Day 2 Measured with an eye-tracking camera
Heart rate deceleration — Day 1 Measured with an electrocardiogram
Heart rate deceleration — Day 2 Measured with an electrocardiogram
Brain activation — Day 1 Neural activation in reward circuits measured with functional magnetic resonance imaging
Brain activation — Day 2 Neural activation in reward circuits measured with functional magnetic resonance imaging
Trial sites (1)
Facility
City
Region
Status
Centre for Addiction and Mental Health
Toronto
Ontario
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This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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