Assessing Mobile Apps for Adult ADHD

Inclusion Criteria: * The participant is aged 18-50 years at time of consent * Fluent in English. * Available for 2 contiguous months to participate in study, including 3 in-person visits to the university. * Able to sit in a regular chair for 30 minutes in a small room for testing. * Able to use a keyboard with both hands. * Normal or corrected to normal vision and hearing. * Have a smart Phone. * Estimated Intelligence Quotient (IQ) \> 80 as assessed by the Wechsler Abbreviated Scale Intelligence (WASI-II) Matrix Reasoning and Vocabulary subtests. * Meet established Diagnostic and Statistical Manual of Mental Health-Fifth Edition (DSM-5-TR) presentation for ADHD predominantly inattentive or combined subtype with clinically significant levels of impairment, diagnosed by semi-structured clinical interview and the Adult ADHD Clinical Diagnostic Scale (ACDS). Exclusion Criteria: * History of diagnosis of childhood neurodevelopmental disorder including autism spectrum disorder and dyslexia, other than ADHD or those specifically allowed in the Allowed Disorders section. * Lifetime history of DSM5 bipolar disorder, psychotic disorder, panic disorder, agoraphobia, obsessive compulsive disorder as assessed with the MINI International Neuropsychiatric Interview (MINI). * Current DSM5 diagnosis of posttraumatic stress disorder, or Major Depressive Disorder or Major Depressive Episode via self-report or as assessed with the MINI. * Current Persistent Depressive Disorder (Dysthymia) or Anxiety Disorder if not on allowed medication that has been at a stable dose for at least 8 weeks (if on allowed medication with stable dose for 8 weeks, then allow). * Substance or Alcohol Use Disorder rated as moderate or severe, with symptoms ≥ 4, as assessed by the MINI, or self-report of a Substance/Alcohol Use Disorder (allow endorsement of substance or alcohol use that does not meet moderate-severe use disorder criterion, if clean at visit). * History of severe sleep disorder, narcolepsy, epilepsy/seizure disorder, brain tumor, stroke, TBI, severe concussion resulting in loss of consciousness and hospitalization, serious oxygen deprivation (such as following heart attack, carbon monoxide poisoning, near drowning or near suffocation), encephalitis, meningitis, or other major neurological disorder. * History of chronic fatigue syndrome, Long-COVID. * Other medical or psychiatric conditions that are sufficient to likely compromise current attentional function and assessment in the opinion of the investigator. * Current ongoing treatment, deemed by the participant and their PCP as indicated for continued use during the study, with psychotropics suspected to alter attentional functioning such as antipsychotic medications, sedative hypnotics, mood stabilizers, benzodiazepines, atypical antidepressants, or anticonvulsants (listed in the Excluded Medications List, or in the opinion of the investigator are likely to interfere with study cognitive assessments). * Participant is currently considered a suicide risk in the opinion of the Investigator, has previously made a suicide attempt, or has a prior history of, or is currently demonstrating active suicidal ideation or self-injurious behavior as measured by Columbia Suicide Severity Rating Scale at screening. * Current treatment with guanfacine (due to the unacceptable risks of rapid withdrawal) and other medications for focus and attention problems such as Strattera, Modafinil, Armodafinil, and Clonidine that require long wash out periods (see Excluded ADHD Medications List). * Participant plans to initiate during the primary study new concomitant prescription medications that are on the Excluded Medications List. * Participant plans to initiate during the primary study behavioral therapy or training to improve cognition by means of game or app-based cognitive trainings or neurofeedback.