The treatment will be administered in an individual format and consist of seven to nine sessions of 45 minutes over a period of seven to nine weeks. The number of sessions can vary to be able to accommodate the fact that participants may have different levels of motivation for changing their primary problem behavior, which is why some participants may require one or two extra sessions at the start of the treatment. The treatment will be offered to participants both in person and via video link to facilitate participation for children and adolescents living further away from the participating clinics.

The patients in this arm will get treatment as usual at their Child and Adolescent psychiatry clinic.

The treatment consists of three parts: 1) setting goals, 2) understanding and identifying high-risk situations and problem behaviors, and 3) consolidating the new activity schedule and identifying future high-risk behaviors. The first part is focused on examining the patient's undesirable behavior, his/her motivation for change, and establishing goals with the. The second part, drawing more from traditional Cognitive Behavioral Therapy (CBT) techniques, consists of exploring problematic situations, identifying high-risk situations and events, emotions and cognitions that induce the problematic gaming behavior or result in a relapse; managing game time with activity scheduling and practicing problem-solving skills. The final part consists of recognizing early warning signals that may indicate that the primary problem behavior is more likely to occur and consolidating the parts of the treatment that have been most helpful in maintaining the new activity schedule.

Changes in gaming measured with Game Addiction Scale for Adolescents (GASA) . GASA applies to gaming behavior during the last 6 months with 7 items. Each question covers one criterion in the Diagnostic and Statistical Manual 5 (DSM-5), answered on a 5-point Likert scale ranging from 1 (never) to 5 (very often) and should according to the developer be counted as endorsed when rated 3 or higher.

Min: 0 Max: 35 A higher outcome means worse gaming problems

Changes in gambling measured with National Opinion Research Center (NORC) Diagnostic Screen for Gambling Disorders (NODS), three NODS questions, pertaining to loss of Control, Lying, and Preoccupation (CLiP).

NODS-CLiP is the shorter form of NODS.

Min: 0 Max:3 A higher outcome means worse gambling problems.

Changes in family climate/communication.

Parent-child communication includes six subscales. Items are rated on a five-point Likert scale ranging from 1 (often) to 5 (Never).

Min: 0 Max: 30 A higher outcome means worse communication.

Family climate , includes two subscales, family cohesion and conflict. While family cohesion assesses the bonds between family members, family conflict assesses the conflicts between family members. A total of 11 questions.

Items are rated on a four-point scale, ranging from 1 (not true at all) to 4 (very true).

Min: 0 Max: 44 A higher outcome means worse family climate.