Co-occurence of Mental Illness and Problematic Alcohol Use: an Internet-based Cognitive Behavior Therapy Intervention

The goal of this clinical trial is to learn if internet-based cognitive behavior therapy (ICBT ) works to treat co-occurent of problematic alcohol use and mental illness including mild to moderate symptoms of either depression, anxiety, stress or disturbed sleep. The main questions the study aims to answer are: * Does the ICBT program lower the self-rated suffering from mental illness? * Does the ICBT program lower the self-reported alcohol intake? Researchers will compare the ICBT program to the participants who are rancomized to a control grout that receives weekly attention from the research team, to see if the treatment works. In both groups, the participants will have the opportunity to ask for support from a therapist during the week days. Participants are adults living in Sweden. They will: * Receive an ICBT program supported by a trained therapist. It consists of modules that the participants will work with on their computer for 10 weeks. Some modules will be compulsory and other optional for the participants. * Fill out forms to rate their mental illness and alcohol intake at the start and the end of the study as well as once every week during treatment. Primary outcome measures are depression, anxiety and stress symptoms (measured with Depression Anxiety and Stress Scale 21 (DASS-21)) and alcohol intake measured with self-reported amounts. Other, secondary, outcome measures used will for example be about insomnia symptoms and disability assessment. Pre-treatment measurement, post-treatment measurement and 6-months and 12-months follow up is planned to be collected through an online survey.