Cortical Excitability and Inhibition in MDD


About this study

The purpose of this study is to learn if measures of brain activity are different in children and adolescents with depression who are in different stages of treatment. This is important because it may identify a biological marker for depression that could one day be used to identify depressed children who would benefit from certain treatments (medications for example), or to monitor how well treatments are working. Brain activity measures(known as cortical excitability and inhibition) will be collected by Transcranial Magnetic Stimulation (TMS). TMS is a noninvasive (no surgery or implants) brain stimulation technology which can make parts of the brain work without putting any wires or chemicals into the body. Measurements will take place over one 3-hour visit. This study does not provide any form of treatment.

*There is an optional portion of the study that uses a brain scan to gather measures of brain structure and brain chemicals. The brain scan is called magnetic resonance and spectroscopy (MRI/MRS). MRI/MRS uses magnetic fields to study the structure of the brain and brain chemicals. The PI will determine eligibility for the MRI/MRS portion of the study.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Adolescents from the ages of 13 to 21, male or female.
  • Subjects with MDD (groups 2, 3, and 4):
  • Must have a Children's Depression Rating Scale, Revised (CDRS-R) score of 40 or higher
  • Must have a Clinical Global Impression-Severity scale (CGI-S) score of 4 or higher.
  • Group 1: (50 subjects): Subjects who have mild (CDRS-R score < 40) but clinically significant depression.
  • Group 2: (50 subjects): Subjects with moderate to severe MDD who have not yet initiated treatment with an SSRI.
  • Group 3: (50 subjects): Subjects with moderate to severe MDD that has responded to treatment with an SSRI.
  • Group 4: (50 subjects): Subjects with moderate to severe MDD which has not responded to treatment with an SSRI.
  • Capable of providing informed assent (consent if age 18) in addition to consent by parent or guardian.
  • Subjects and at least 1 parent must be fluent in English.

Exclusion Criteria:

  • Primary Axis I or II disorder other than MDD.
  • Unprovoked seizure history, seizure disorder, history of febrile seizures, family history of epilepsy.
  • Any significant findings on the TMS Adult Safety Screen (TASS) or contraindications to MRI/MRS
  • Subjects who are judged by the Principal Investigator to be at imminent risk for self harm or suicide as indicated by interview or C-SSRS.
  • Pregnancy or suspected pregnancy in females.
  • Metal in the head (except the mouth*), implanted medication pumps, cardiac pacemaker. * Subjects with braces will be excluded from MRI/MRS portion of study only
  • Prior brain surgery.
  • Risk for increased intracranial pressure such as a brain tumor.
  • Any unstable medical condition.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status

Rochester, Minn.

Mayo Clinic principal investigator

Paul Croarkin, D.O., M.S.

Closed for enrollment

More information


Publications are currently not available

Mayo Clinic Footer