Self-help Smartphone-delivered Cognitive Behavioral Therapy for Insomnia in People With Depression and Insomnia

Stage 1 Screening (Online Survey) Inclusion Criteria: * Hong Kong residents * age ≥ 18 years * predominant complaint of difficulty initiating or maintaining sleep or early morning awakening or non-restorative sleep with associated distress or impairment in social, occupational and other important areas of functioning for at least three nights per week for at least three months * Insomnia Severity Index score ≥ 8 * Patient Health Questionnaire (PHQ-9) score ≥ 10 * being able to read Chinese and type Chinese or English * have a smartphone device (iOS or Android operating system) with Internet access * have a regular email address * willing to give informed consent and comply with the trial protocol Stage 1 Screening (Online Survey) Exclusion Criteria: * Beck Depression Inventory II (BDI-II) suicidal ideation score ≥ 2 * receiving concurrent psychological treatment at least once per month * former proACT-S pilot clinical trial participants * currently taking prescribed psychiatric drugs such as antidepressants, tranquilizers, sleeping pills regularly * carrying a diagnosis of psychosis or schizophrenia * participating in any other academic studies or clinical trials related to insomnia and/or depression Stage 2 Screening (Telephone Diagnostic Interview) Inclusion Criteria * difficulty initiating sleep, maintaining sleep, or early-morning awakening with inability to return to sleep at least once in the past two weeks * International Statistical Classification of Diseases and…