The actual treatment project aims to evaluate if adults with ADHD can benefit from psychological treatment delivered through Internet. About 150-200 patients will be recruited through several outpatient clinics in Stockholm. They will be randomized to one of three conditions - active psychological treatment (based on CBT and DBT), an active alternative treatment where they undergo a psychoeducational support program (based on CBT) or to treatment as usual (TAU) / waiting list. The patients in the treatment conditions will have a personal contact via the internet with a psychologist within the 12 week treatment period. Assessments will be done before, during and after treatment, and after 3 and 12 months. The patients in the TAU condition will be offered iCBT treatment after they have filled out the post assessments (after 12 weeks and at 3rd month after treatment).