COVID-19 pandemic (residential treatment center closed to visitors)

The purpose of the study is to evaluate the use of a new brain stimulation tool called transcranial direct current stimulation (tDCS). tDCS is a new technique used to stimulate the brain. The investigators believe that it may help to change brain function in individuals with anorexia nervosa. The brain stimulation occurs outside the head. The tDCS procedure involves applying a small amount of electrical current across the scalp, for a short period of time. This small electrical current is able to change the electrical activity inside areas of the brain. In the current study, the investigators will ask participants to complete computer-based brain training sessions. While participants do the brain training exercises, they will receive either real tDCS for "sham" tDCS. "Sham" tDCS means that participants might feel sensations like tingling or vibrations from the tDCS machine, but will not actually receive the electrical current. Investigators will also ask participants to complete several tests to assess changes in brain function. The information gained from this study will help investigators to understand how tDCS could be used to improve brain function and learning in individuals with anorexia nervosa.

Inclusion Criteria:

• Age 18+ years
• Documented enrollment in residential-level treatment at The Emily Program and meeting criteria for AN (BMI <18.5).
• Participant must be capable of giving informed consent, based on University of California San Diego (UCSD) Brief Assessment of Capacity to Consent (UBACC)39 risk assessment, which has been uploaded to ETHOS.
• Sufficient spoken English so as to be able to comprehend testing procedures.

Exclusion Criteria:

• Substance abuse in the participant
• Neurological condition or other developmental disorder
• Serious psychiatric disorder known to affect brain functioning and cognitive performance
• Medical instability, which will be evident based on required admittance status in the residential treatment facility from which participants will be recruited. (The Emily Program residential treatment patients are followed closely by a medical provider, who routinely assesses medical stability throughout the duration of each patient's stay in the treatment facility; therefore, if a participant is not currently a patient in this setting and/or has been recently discharged from residential treatment setting due to medical need to receive higher level of care/inpatient-level care, they will be excluded from enrollment in this study).
• MRI contraindication [based on Center for Magnetic Resonance Research (CMRR) prescreening protocol]
• tDCS contraindication (e.g., history of craniotomy, history of metallic cranial plates, screws, implanted devices).

There is no plan to share Individual Participant Data (IPD) with other researchers.

One arm of this study is a sham condition; both tDCS and sham tDCS conditions are blinded to participants and study assessor/s.