Efficacy of an Internet-based Psychological Intervention for Problem Gambling and Gambling Disorder

Inclusion Criteria: * Be 18 years or older. * Willingness to participate in the study and sign informed consent. * To have and handle the computer, Internet and an email address. * Ability to understand, read and write Spanish. * Based on the cut-off points established by the Norc diagnostic screen for gambling disorders (NODS; adapted by Becoña, 2004): be a problem gambler (3-4 items) or a pathological gambler (5 or more items). * Willingness to provide the name of a co-therapist to validate the information provided, as well as to be able to locate the patient in follow-ups. * Willing to provide follow-up data on gambling. Exclusion Criteria: * Any serious mental disorder (Bipolar and Related Disorders and Schizophrenia Spectrum and Other Psychotic Disorders), medical illness, and moderate or severe alcohol and/or substance use disorder, that prevents the program from being carried out. * If their gambling behaviour occurs in the context of a Maniac Episode or because of the intake of dopaminergic medication (e.g. Parkinson's disease). * The presence of high suicidal risk. * Receiving another psychological treatment while the study is still ongoing. * Receiving pharmacological treatment is not an exclusion criterion during the study period, but participants having an increase and/or change in the medication 2 months prior to enrollment will not be considered for the trial. Also, the increase and/or change in the medication during the study period in the experimental group…