Table 1

List of included components and their definitions

w Waiting componentParticipants are aware that they can receive an active treatment after a waiting phase. Usually patients on a wait list do not receive any sort of treatment during the waiting phase. However, in some trials patients allocated to the waiting list control condition receive some non-specific therapeutic components such as psychological placebo, psychoeducation or treatment as usual while waiting. In such cases, we will consider that the ‘waiting component’ (w) is present and also record the interventions provided while waiting.
Sometimes publications are not clear if their control conditions allowed the intervention to be administered after the last assessment: in such cases, we need to check the published protocol, trial registries, secondary publications from the same trial and/or ask the original authors.
dt Conventional drug treatmentTreatment as usual or care as usual can denote many different conditions in the literature.21 In this study, we focus on the presence of ‘conventional drug treatment’ and extract the data if it is present (drug treatment is part of the protocol treatment), allowed (we will note the percentage of patients on drug) or absent.
pl Placebo effectEffect of an intervention due to the patients’ belief that they are receiving some form of treatment.
In trials, Hawthorne effect can be considered to be always present because all the participants, in the intervention or the controls, will be evaluated. We therefore will drop considering Hawthorne effect as a component in this component NMA.
There will be a few trials that may teach skills not covered in this classification (eg, ‘expressive writing’ and ‘dreamwork’). We assume such miscellaneous interventions to have some placebo effect. However, it is possible that some of them may possess some effect beyond placebo effect. We will examine the robustness of our assumption by conducting a sensitivity analysis excluding any studies that taught such miscellaneous skills not categorisable here.
pe Psychoeducation about depressionProvision of information about the cause and nature of depression. Patients are taught their symptoms can be interpreted under a certain psychopathological model. For example, if cognitive distortion is cited as the cause of depression, such explanation will count towards pe as defined here.
Advice about lifestyle modification (eg, exercise, food and sleep hygiene (as opposed to CBT for insomnia)) will be regarded as form of psychoeducation.
Provision of information about depression in informational websites will count towards psychoeducation.
cr Cognitive restructuringThis component teaches the patient to evaluate and modify their own irrational, maladaptive or dysfunctional thoughts using strategies such as Socratic questioning and guided imagery.
ba Behavioural activationThis component aims at helping people increase potentially reinforcing experiences through activity scheduling and increased engagement in pleasant activities.
is Interpersonal skill trainingTraining in appropriate social behaviours. Includes assertiveness training that teaches the patient to stand up to their own rights by expressing their feelings and wishes in an honest and respectful manner that does not insult or hurt the others.
ps Problem solvingThis skill includes the following step-by-step approach to personal problems: defining personal problems, generating multiple solutions, selecting the best solution, working out a systematic plan for this solution and evaluating whether the solution has resolved the problem.
re RelaxationThis skill is aimed at reducing general tension through induction of a relaxed body state. The most common technique is Jacobson’s progressive muscle relaxation or applied relaxation.
3w Third-wave componentsVarious techniques aimed at helping patients to develop more adaptive emotional responses to situations, such as the ability to observe symptomatic processes without overly identifying with them or without reacting to them in ways that cause further distress.56 Some typical examples include training in mindfulness, self-compassion or acceptance.
bi Behaviour therapy for insomniaThis skill aims at treating chronic insomnia based on the principles of sleep restriction and stimulus control. It may also involve cognitive restructuring around maladaptive beliefs for sleep. It may also involve teaching sleep hygiene; however, sleep hygiene only would count towards lifestyle modification.
rp Relapse preventionReview of learnt skills and listing action plans for the foreseeable future problems based on the skills learnt. A mere explanation of relapse in depression will only count towards psychoeducation; in order to qualify for relapse prevention component, it needs more participation from the patient.
hw Homework requiredWhen completion of some homework assignment is required (or explicitly encouraged repeatedly) before proceeding with the programme, either checked by humans or mandated by the programme. The homework must pertain to exercise in applying the learnt CBT or other skills in one’s own situations and must require some active participation from the participant. Simple reviewing of the materials or further reading will not be regarded as homework.
ff Initial face-to-face contactInitial face-to-face human contact, such as the initial evaluation session or the initial orientation session, is present. In conventional drug treatment, ff is considered to be present.
ae Automated encouragement to proceed with iCBTProvision of automated, fixed prompts/encouragements to proceed with the treatment programme. Such prompts should not contain any support related to the therapeutic contents.
he Human encouragement to proceed with iCBTPrompts/encouragements are prepared and provided by human beings to proceed with the treatment programme via telephone or email. Such prompts should not contain any support related to the therapeutic contents.
Peer support such as discussion group will be counted towards this component.
tg Therapeutic guidance for iCBTGuidance as to the contents of iCBT. Therapeutic guidance related to the treatment content may be provided on a scheduled basis or as-needed basis. Provision of technical support only is not counted towards this component.
  • iCBT, internet-delivered cognitive–behavioural therapy; NMA, network meta-analysis.