Cognitive Behavioral Therapy for Insomnia in Type 2 Diabetes Mellitus

Inclusion Criteria: * Type 2 diabetes mellitus age 30 to 65 years old * Hemoglobin A1C ≥ 6.5 but ≤ 10 % * Have poor sleep quality as assessed by Insomnia Severity Index ≥ 15 * Receive the same hypoglycemic treatments 3 months before the intervention * If using sleep aid, the dose needs to be stable for 3 months prior to the enrollment * Ability to use the electronic devices (computer, tablet) and assess the internet * Willing to attend all of the 8 sessions activities Exclusion Criteria: * Type 1 diabetes mellitus * Night shift work * Insulin therapy * Severe hypoglycemia who required hospitalization or emergency department visit in the past 6 months * History of diabetic ketoacidosis in the past 6 months * Medically unstable conditions eg. renal replacement therapy, liver failure, heart failure, active cancer, epilepsy, unstable cerebrovascular disease * Psychosis, uncontrolled depression * Untreated obstructive sleep apnea or STOP-BANG ≥ 5 * Language/communication/hearing/sight disability * Pregnancy or lactation * Care giver of infant * Harmful alcohol/smoking (≥15 standard-drink in men and ≥8 standard-drink in women)