The Comet-program is a Swedish parent training program developed to target externalizing behaviors in children between 3-11 years. The program is normally delivered in group format in primary and specialized care and has already been evaluated in several studies. The internet-based version of the program has also been evaluated separately, but in this study the two formats will be directly compared in a randomized non-inferiority study. Parent ratings, child ratings as well as blinded clinical assessments will be conducted before the interventions, after the interventions (2-3 month after start of intervention), and at follow-up (12 mont after first assessment). The primary research question is: Will the internet-based format of Comet be at least as effective as the group format in reducing externalizing behaviors? Secondary research questions concern possible differential effects of the two formats on cost-effectiveness, parenting behaviors, parent mental health, applicability and consumer satisfaction, and the children's quality of life.

Background:

The Comet-program is a Swedish parent training program developed to target externalizing behaviors in children between 3-11 years. The program content is behaviorally oriented and the emphasis lies on increasing parenting behaviors that reinforces pro-social behaviors in children, as well as limiting the reinforcement of anti-social behaviors. The program is manualized and normally delivered in group format with parents to 6-8 children in each group. The group sessions (11 sessions á 2.5 hours) are led by two practitioners and include information, role-playing, and home-work exercises. The group format has been evaluated in two large randomized controlled studies. The effect sizes on child externalizing behaviors have been medium to large (Cohen´s d). Because of the evidence supporting Comet and other research supporting the effectiveness of similar behavioral parenting programs, Comet has been implemented in primary and specialized care in Sweden. A challenge in primary care is however the implementation costs related to the program (e.g., training of group leaders and the time each group leader need to invest in each patient). Therefore, Comet (or similar programs) are in practice used to a small extent in primary care, despite clear recommendations to offer such treatments for externalizing behaviors. A possible solution would be to offer an internet-based version of the program, which in two large randomized controlled trials have shown medium effect sizes on externalizing behaviors in children. In the internet-based version, the patients (parents) work online with seven modules over a period of nine weeks. Every module contains information, video-clips, quizzes and homework exercises. Every week the patient communicates with a therapist, that gives brief guidance and feedback online.

The internet-based format of the program has however been implemented at a very small scale in regular care. One reason is probably reluctance on part of practitioners as well as patients in replacing face-to-face contact with online-contact. The management system used in health-care in Sweden is another obstacle, since only face-to-face contacts are included. Hence, the clinics are not financially compensated for any patient contacts online. To overcome these obstacles, the present study will compare the regular Comet program in group format to a modified version of the internet-based version. In the modified version, the online contact between the patient and the therapist will be replaced with three individual face-to-face sessions (45 min each). This will reduce the total amount of time invested per patient to 135 mins, compared to 410-550 mins per patient in the group format.

Research questions:

The primary research question in the study is: (1) Will the internet-based version of Comet be at least as effective as the group format in reducing externalizing behaviors in children?

The secondary research questions will be to investigate if the two formats of Comet will differ in terms of: (2) cost effectiveness, (3) consumer satisfaction/applicability for patients as well as practitioners, (4) effects on parent behaviors and mental health, (5) effects on the quality of the relationship between parents and children, (6) effects on the quality of life experienced by the children, and (7) if the application of parenting strategies included in Comet mediates change in child externalizing behaviors.

Method:

To investigate these research questions, parents seeking help in primary care clinics for externalizing behaviors in their child will be recruited to the study. Six clinics will be involved in recruitment of participants and offering the interventions. Clinical psychologists on every clinic will therefore be trained in both formats of the Comet program.

Enrolled participants will be randomized at each clinic to either take part in the group format or the internet-based format of Comet. The participants randomized to the latter format will start their treatment as soon as they have completed the first assessment, while participants in the group format will have to wait for the scheduled group to start (generally within 1-3 months after enrollment and first assessment). The post assessment will take place when participants have completed the intervention and the follow-up assessment will be 12 months after the first assessment point. In addition, parents in each condition will answer a few questions on a weekly basis during their interventions.

Assessments at pre, post and follow-up will include parent ratings of child behaviors, parent behaviors, parent mental health, and consumer satisfaction/applicability (only at post assessment). At pre and post assessment blinded clinicians will also make a diagnostic assessment of Oppositional Defiant Disorder (ODD) and Attention Deficit/Hyperactivity Disorder (ADHD) symptoms of the participating children. When the clinician meets the child for these assessments, the child will also be answering questions (structured interview) regarding their experienced quality of life. Finally, the psychologist involved in the treatments will continuously take notes in a log-book for each participant. The log-book will contain information on parent attendance, adherence and adverse events. A selection of the treating psychologists will also be interviewed to assess their experienced applicability of the two formats of Comet.

The weekly questions will measure child externalizing behavior and the extent to which the parents have completed homework exercises (parenting strategies).

Since the primary research question is if the internet-based version of Comet is at least as effective as the group format, the power calculation was based on non-inferiority design. The first step is to decide the non-inferiority margin, which is the least acceptable difference between the conditions in order to conclude that the internet-based version is non-inferior. A conventional method for deciding this margin is to use 50% of the effect sizes found in previous studies of the already established intervention. When applying this method for the primary outcome measure, the calculation showed that 134 participants were necessary to include in order to achieve a power of 0.80. In other words, if there is truly no difference between the group format and the internet-based format, then 134 patients are required to be 80% sure that the lower limit of a one-sided 95% confidence interval (or equivalently a 90% two-sided confidence interval) will be above the non-inferiority limit.

Most research question will be analyzed using methods from non-inferiority design, i.e., analyzing the difference between adjusted means at post and follow-up with regard to the non-inferiority margin. Primarily, these analyses will be performed on participants who completed the interventions and assessments (per protocol), since intention-to-treat analyses reduces power and increase the risk falsely concluding non-inferiority.

For the second research question (cost-effectiveness), the clinical significance in each condition will be calculated and compared (i.e., the proportion of participants that have "recovered", "improved", are "unchanged" or have "deteriorated). Thereafter, the cost per patient for each treatment will be calculated and used to achieve an estimate of cost per recovered/improved participant. This method has previously been applied in a cost-effectiveness analysis of Comet and other parenting programs.

The analyses of practitioner satisfaction and experienced applicability will mainly be descriptive, due to lack of power (to few practitioners involved in treatment) and due to fact that part of the data is qualitative (interviews).

Finally, the analyses of mediation (research question 7), will be analyzed using Latent Growth Curve Modeling, which is suitable for data that is measured repeatedly during an intervention.

Inclusion Criteria:

• Primary reason for contact with health care is child externalizing behaviors.

Exclusion Criteria:

• Not sufficiently fluent in written Swedish to be able to take part in an internet-based (text-based) intervention.
• No access to computer/ipad/phone
• Social problems that makes investigation or intervention from the social services necessary.

This has not yet been decided by the research team, but the information will be updated as soon as a decision has been reached.

Independent clinicians will perform diagnostic assessments at pre and post measurements. The clinicians will be blind to the experimental condition the participants they assess.