Developing novel measures and treatments for gambling disorder

Background: While gambling is an activity that seems to have entertained humanity for millennia, it is less clear why problematic gambling behavior may persist despite obvious negative consequences, from a research and clinical perspective. With the introduction of the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM–5), gambling was equated with alcohol and drug use and labeled an addictive disorder, Gambling Disorder (GD). Problem gambling is associated with destroyed careers, broken marriages, financial ruin, and psychiatric comorbidities. Still, research on gambling can be described as a field still in its infancy, with a need to conduct further gambling research on measurement and treatment procedures. Aims: The overall aim for the thesis was to develop and evaluate measures and treatments for Gambling Disorder. The aims of Study I were to reach a consensus regarding a specific set of potential new measurement items, to yield a testable draft version of a new gambling measure, and to establish preliminary construct and face validity for this novel gambling measure, the Gambling Disorder Identification Test (GDIT). The aim of Study II was to evaluate psychometric properties (e.g., internal consistency and test-retest reliability, factor structure, convergent and discriminant validity, as well as diagnostic accuracy) of the GDIT, among treatment- and support-seeking samples (n = 79 and n = 185), self-help groups (n = 47), and a population sample (n = 292). The aim of Study III was to formulate hypotheses on the maintenance of GD by identifying clinically relevant behaviors at an individual level, among six treatmentseeking participants with GD. This qualitative study was conducted as a preparatory step to develop the iCBTG (see Study IV). The aim of Study IV was to evaluate acceptability and clinical effectiveness of the newly developed iCBTG, among treatment seeking-patients with GD (n = 23) in routine care. A further aim was to evaluate research feasibility of using existing healthcare infrastructure to deliver the iCBTG program. Methods: In Study I, gambling experts from ten countries rated 30 items proposed for inclusion in the GDIT, in a two-round Delphi (n = 61; n = 30). Three following consensus meetings including gambling researchers and clinicians (n = 10; n = 4; n = 3), were held to solve item-related issues and establish a GDIT draft version. To evaluate face validity, the GDIT draft version was presented to individuals with experience of problem gambling (n = 12) and to treatment-seeker participants with Gambling Disorder (n = 8). In Study II, the psychometric properties of the GDIT were evaluated among gamblers (N = 603), recruited from treatment- and support-seeking contexts (n = 79; n = 185), self-help groups (n = 47), and a population sample (n = 292). The participants completed self-report measures, a GDIT retest (n = 499) and a diagnostic semi-structured interview assessing GD (n = 203). In Study III, treatment-seeking patients with GD and various additional psychiatric symptom profiles (n = 6), were interviewed using an in-depth semi-structured functional interview. Participants also completed self-report measures assessing gambling behavior. A qualitative thematic analysis was performed using functional analysis as a theoretical framework. Following completion of Study III, the results were synthesized with existing experimental evidence on gambling behavior and used to develop the novel treatment model and internet-delivered treatment evaluated in Study IV, i.e., the iCBTG. In Study IV, a non-randomized preliminary evaluation of the novel iCBTG was conducted in parallel with implementation into routine addiction care, through the Support and Treatment platform (St d och behandlingsplattformen; ST platform). Feasibility was evaluated among a sample of treatment-seeking patients (N = 23), in terms of iCBTG adherence, acceptability and clinical effectiveness, and feasibility of using existing healthcare infrastructure for clinical delivery as well as research purposes. Results: Study I established preliminary face validity for the GDIT, as well as construct validity in relation to a researcher agreement from 2006 on measuring problem gambling, known as the Banff consensus. Study II showed excellent internal consistency reliability (α = .94) and test–retest reliability (6-16 days, intraclass correlation coefficient = 0.93) for the GDIT. Confirmatory factor analysis yielded factor loadings supporting the three proposed GDIT domains of gambling behavior, gambling symptoms, and negative consequences. Receiver operating characteristic curves (ROC) and clinical significance estimates were used to establish GDIT cut-off scores for recreational gambling (