Can brain training help depressed young adults stop ruminating?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Young adults ages 18-35 * Participants who are able to give written informed consent prior to participation * Meeting DSM-5 diagnostic criteria for MDD who are currently depressed defined by the MINI * Participants who have RNT symptoms (Brooding subscale of Ruminative Response Scale: RRS-B ≥ 13) Exclusion Criteria: * Moderate to severe traumatic brain injury (\>30 min. loss of consciousness or \>24 hours posttraumatic amnesia) or other neurocognitive disorder with evidence of neurological deficits * Presence of co-morbid medical conditions not limited to but including cardiovascular (e.g., history of acute coronary event, stroke), pulmonary, endocrine, neurological diseases (e.g., Parkinson's disease), or gastrointestinal illness, as well as pain disorders * Current significant suicidal ideation or suicide attempt within the previous 12 months * Current psychosis * Schizophrenia or schizoaffective disorder * Substance use disorder within the previous 12 months, except for mild alcohol, cannabis, or tobacco use disorder defined as less than 4 symptoms of the criteria for substance use disorder according to the MINI * Current diagnosis of post-traumatic disorder (PTSD) defined by the MINI * Severe claustrophobia * Bodily implants of unsafe paramagnetic materials such as pacemakers and aneurysm clips * Pregnancy * Current regular use of cardiovascular medications with a direct vasomotor effect, namely beta- or alpha-beta-blockers, clonidine, and antianginal agents. * Current use of more than three psychotropic medications * Evidence of recreational drug use from a urine test * Commencement of psychotropic medication for depression and/or anxiety less than a month before the study enrollment * Commencement of psychological therapy less than a month before the study enrollment * Participants who have a clinically significant or unstable cardiovascular, pulmonary, endocrine, neurological, gastrointestinal illness or unstable medical disorder will be excluded * Participants who, on arrival to the study, have a temperature greater than 100.4°F will not be allowed to initiate the study * The majority of the assessments proposed for this study have not been translated from English, thus, non-English speaking volunteers will be excluded