Effects of CBT-I on Impulsivity and Risk Taking in Youths With Insomnia

Inclusion Criteria: * Chinese aged 12-24 years old * Written informed consent of participation in the study is given by the participant and his/her parent or guardian (for those aged under 18) * Willing to comply with the study protocol * Meeting the DSM-V diagnostic criteria of insomnia disorder and with a score on Insomnia Severity Index (ISI) \>= 9 (suggested cut-off for adolescents) Exclusion Criteria: * A current diagnosis of substance abuse or dependence; a current or past history of manic or hypomanic episode, schizophrenia spectrum disorders, neurodevelopmental disorders, organic mental disorders, or intellectual disabilities * Having a prominent medical condition known to interfere with sleep continuity and quality (e.g. eczema, gastro-oesophageal reflux disease) * Having a clinically diagnosed sleep disorder (other than insomnia disorder) that may potentially contribute to a disruption in sleep continuity and quality, such as narcolepsy, sleep-disordered breathing, and restless leg syndrome, as ascertained by the Structured Interview for Sleep Patterns and Disorders (DISP), a validated structured diagnostic interview to assess major sleep disorders according to the International Classification of Sleep Disorder (ICSD) criteria * Concurrent, regular use of medications(s) known to affect sleep continuity and quality including both western medications (e.g. hypnotics, steroids) and over-the-counter OTC medications (e.g. melatonin, Traditional Chinese Medicine, TCM) * In the opinion of the research clinician, having a clinically significant suicidality (presence of suicidal ideation with a plan or an attempt) * Currently receiving any psychological treatment for insomnia * With hearing or speech deficit * Night shift worker