Digital Mood-enhanced CBT-I to Improve Depressive Symptoms in Adolescents

This trial is testing a digital version of CBT-I (Cognitive Behavioral Therapy for Insomnia) — a structured program that changes sleep habits and thought patterns — delivered through an app, specifically designed for Chinese teenagers who have both insomnia and depression. **You may be eligible if...** - You are a Chinese teenager aged 12–18 - You have insomnia (scoring 9 or higher on the Insomnia Severity Index) - You have depressive symptoms (scoring 10 or higher on the PHQ-9 questionnaire) - You can read and understand Chinese - You own a smartphone **You may NOT be eligible if...** - You have significant suicidal thoughts, plans, or past attempts - You have been diagnosed with psychosis, schizophrenia, bipolar disorder, or intellectual disability - You have another sleep disorder (like sleep apnea or restless legs) that significantly disrupts sleep Talk to your doctor to see if this trial is right for you.