Inclusion Criteria  Between 25 and 40 years old; Asymptomatic on the Sleep Disorders Symptoms Checklist-25 (except for insomnia in the insomnia groups)  Additional inclusion criteria for the control group:  Asymptomatic on the SCI (i.e. score >3 on all items)Patient Health Questionnaire (PHQ-9) score < 10 Primary Care PTSD Screen (PC-PTSD) score < 3 No current diagnosis of mental disorder confirmed by the M.I.N.I.  Additional inclusion criteria for the insomnia group:  Symptomatic on the SCI (i.e. score above <3 on specific combination of items (see 64))Patient Health Questionnaire (PHQ-9) score < 10 Primary Care PTSD Screen (PC-PTSD) score < 3 No current diagnosis of mental disorder confirmed by the M.I.N.I.  Additional inclusion criteria for the insomnia+PTSD group:  Symptomatic on the SCI (i.e. score above <3 on specific combination of items (see 64))Current diagnosis of PTSD confirmed by the PC- PTSD Screen (score > 3) and the PTSD scale of the M.I.N.I.) No current diagnosis of bipolar disorder or psychotic disorder confirmed by the M.I.N.I.  Additional inclusion criteria for the insomnia+Depression group:  Symptomatic on the SCI (i.e. score above <3 on specific combination of items (see 64))Current diagnosis of major depressive disorder or persistent depressive disorder confirmed by the Patient Health Questionnaire (PHQ-9) score > 10 and the MDE scale of the M.I.N.I.; No current diagnosis of bipolar disorder, psychotic disorder or PTSD confirmed by the M.I.N.I. Primary Care PTSD Screen (PC-PTSD) score < 3  Exclusion Criteria  Brain injury with loss of consciousness for over 5 minutes. Self-reported substance use disorder or > monthly use of illicit drugs reported on item-2 of the WHO-ASSIST Body mass index > 45; Shift work or rotating shifts within 1 month of study entry; Recent travel to a difference time zone; Any clinically significant cardiopulmonary, gastrointestinal, pancreatic, hepatic, renal, hematologic, endocrine, neurological (including seizure disorder), urogenital, or sleep disorder (other than insomnia); Not passing the COVID-19 screening; Taking any psychotropic medications p.r.n. (If taking any antidepressant or sleep medications, needs to be on a stable dose for at least 1 month prior to study start). Taking stimulant medications including, but not limited to, Adderall, Concerta, Ritalin, Desoxyn, Dexedrine, Dextrostat, Ephedrine, Phentermine, Procentra, Vyvanse, and Selegline; Insufficient English/French skills to provide informed consent, understand study instructions, or fill out questionnaires; Individuals with mini-braids, dreadlocks, hair extension or natural afro-hair (as this can alter the EEG headband recording).