Brain training with mindfulness may quiet repetitive negative thoughts in teens

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

Inclusion Criteria: * Ages 13-21, inclusive * If \<18 years old: Competent and willing to provide written informed assent AND have a parent/legal guardian who is competent and willing to provide written informed consent * If age ≥18 years: Competent and willing to provide written informed consent * Tanner puberty stage ≥3 (to minimize neuroendocrine variability) * Able to understand study procedures, read, and write in English * Access to a mobile device to complete daily surveys Additional Inclusion Criteria for At-Risk Adolescents - Recurrent negative thinking, defined as PTQ/PTQ-C total score \>30 with at least two items rated as 3 (Often) or 4 (Almost Always) Additional Inclusion Criteria for Healthy Controls -PTQ/PTQ-C total score \<15, with zero items rated as 3 (Often) or 4 (Always) Exclusion Criteria: * Any of the following lifetime mental health disorders by DSM-V criteria: psychotic disorders, bipolar disorder, recurrent moderate or severe major depressive disorder, conduct disorder, developmental disorder (e.g., autism), post-traumatic stress disorder, or obsessive compulsive disorder * Severe lifetime substance use disorder * Unstable medical or neurologic condition as determined by study staff, history of epilepsy or seizure disorder, head injury, loss of consciousness \>5 minutes by participant self-report * MRI contraindications (i.e. presence of ferromagnetic implants, cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, magnetic dental implants claustrophobia). * Visual, auditory, or cognitive impairment (IQ\<80 based on the Wechsler Abbreviated Intelligence Scale (WASI)) that may make it difficult to participate. * Any condition or situation that would, in the investigator's opinion, make it unlikely that the participant could adhere safely to the study protocol. * Pregnancy: a negative pregnancy test is required at the time of enrollment for any individuals of childbearing potential * Individuals who are under the legal protection of the government or state (Wards of the State)