Effects of a CT-100 DiNaMo Component on Cognitive Functioning and Mood Symptoms

Inclusion Criteria: A participant will be eligible for entry into the study if all the following criteria are met: 1. Age ranges in years: 22-52 for Multiple Sclerosis, 35-65 for Cancer (Breast or Lung), and 45-75 for Mild Cognitive Impairment. 2. Diagnosis of indication under study (Multiple Sclerosis, Cancer - Breast or Lung, Mild Cognitive Impairment) 3. Self-reported cognitive impairment and mood symptoms that began in the context of the primary indication under study. 4. Fluent in written and spoken English (confirmed by ability to read and comprehend the informed consent form.) 5. Willing and able to comply with study protocol and assessments, evidenced by completion of the Screening Survey. 6. Lives in the United States. 7. Has an active email address and is willing and able to receive email messages. 8. Is the sole user of an iPhone or a smartphone with an Android operating system, and with cellular and/or internet access for the duration of the study period. Exclusion Criteria: A participant is excluded from the study if any of the following criteria apply: 1. Physician-diagnosed insomnia in the Screening Survey. 2. Cognitive impairment/mood symptoms or clinical diagnosis of depression attributed to a condition other than the underlying medical condition. 3. Is currently pregnant or breastfeeding. 4. Substance use disorder within the past 1 year. 5. Initiation or change in central nervous system-active medication (e.g., antidepressants) during the last 2 months. 6. Participation in a clinical trial within the last 3 months. 7. Anticipates a lifestyle change or change in current treatment during the study period that could affect cognitive functioning. 8. Visual, dexterity or cognitive deficit so severe that precludes the use of an app. 9. Severe neurological disorders impairing brain function. 10. Psychiatric hospitalization in the past 6 months.