Glutamate Probes in Adolescent Depression
Condition: Major Depressive Disorder; Major Depressive Disorder, Recurrent; Major Depressive Disorder, Remitted
MeSH terms: Depression; Depressive Disorder; Depressive Disorder, Major
Study type: Observational

Summary: 
      The purpose of this study is to learn if measures of brain chemicals from a brain scan called
      Magnetic Resonance Imaging and Spectroscopy (MRI/MRS) and brain activity (known as cortical
      excitability and inhibition) collected by Transcranial Magnetic Stimulation (TMS) are
      different in adolescents with depression who are in different stages of treatment.

      Researchers are conducting this study to learn more about how the brain works in adolescents
      with depression and without depression (healthy controls). This is important because it may
      identify a biological marker (a measure of how bad an illness is) for depression that could
      one day be used to identify depressed adolescents who would benefit from certain treatments
      (medications for example) or to monitor how well treatments are working.
    

Detailed description: 
      This is a cross-sectional and longitudinal neurophysiology research study of 200 adolescent
      subjects in varying stages of major depressive disorder (MDD). The aims of this study are
      designed to gain an understanding of (1) the role of glutamate in the neurophysiology and
      pharmacologic treatment of child and adolescent MDD; (2) the role of gamma-aminobutyric acid
      (GABA) in the neurophysiology and pharmacologic treatment of child and adolescent MDD; (3)
      the trajectory of glutamatergic and GABAergic functioning in human development with MDD.

      Glutamate concentrations in the anterior cingulate cortex (ACC) and left dorsolateral
      prefrontal (L-DLPFC) cortex will be evaluated using proton magnetic resonance spectroscopy
      (MRS) at 3 Tesla (3T). Glutamatergic cortical excitability measures (with motor threshold and
      intracortical facilitation paradigms), and GABAergic cortical inhibitory measures (with
      cortical silent period and intracortical inhibition paradigms) will be studied using single
      and paired-pulse transcranial magnetic stimulation (TMS) paradigms.
    

Observational model: Case-Control
Time perspective: Other
Sampling method: Non-Probability Sample
Study population: 
        This protocol will plan to screen depressed children and adolescents who are seeking
        treatment at Mayo Clinic in Rochester, MN, using strict inclusion and exclusion criteria.
        These adolescents will represent gender and minority distribution consistent with the
        Rochester metro/rural area demographic distribution. This study will be inclusive of all
        races, genders, and socioeconomic classes.
      
Keywords: Major depressive disorder; MDD; healthy control; selective serotonin reuptake inhibitor; SSRI; depression; transcranial magnetic stimulation; TMS; magnetic resonance spectroscopy; MRS; adolescent; mild MDD; mild depression; cortical excitability; cortical inhibition; cortical silent period; motor threshold; intracortical facilitation; intracortical inhibition; motor cortex; dorsolateral prefrontal cortex; DLPFC; thumb twitch; gamma aminobutyric acid; GABA; glutamate; single pulse; paired pulse