Table 2.

Conceptualisation of some representative forms of iCBT or control conditions according to a component-level perspective

Interventions or controls	Possible decompositions into components
Waiting list	w (±pl±pe±dt)±ff
No treatment	±ff
Attention/psychological placebo (APP)	pl±ff
Treatment as usual (TAU)*	pl+dt±ff
Psychoeducation (PE)†	pl+pe±rp±dt±(ae/he)±tg±ff
Relaxation therapy†	pl(±pe)+re±rp±dt±(ae/he)±tg±ff±hw
Cognitive therapy†	pl (±pe±re)+cr±rp±dt±(ae/he)±tg±ff±hw
Behavioural activation (BA)†	pl (±pe±re)+ba±rp±dt±(ae/he)±tg±ff±hw
Problem-solving therapy†	pl (±pe±re)+ps±rp±dt± (ae/he)±tg±ff±hw
Assertiveness training†	pl (±pe±re)+at±rp±dt±(ae/he)±tg±ff±hw
Cognitive-behavioural therapy (CBT)†	pl (±pe±re)+cr+(ba±ps±at±bi)±rp±dt±(ae/he)±tg± ff±hw
Third-wave CBT (3W)†	pl (±pe±re±cr±ba±ps±at±bi)+3w±rp±dt±(ae/he)±tg±ff±hw

*TAU here must include pharmacotherapy. Watchful waiting or follow-up by community nurses will therefore be classified as APP even when it is ‘treatment as usual’ in some settings.

†Any of these active interventions may be provided with or without TAU.

3W, third-wave components; ae, automated encouragement to proceed with iCBT; bi, behaviour therapy for insomnia; cr, cognitive restructuring; dt, conventional drug treatment; ff, initial face-to-face contact; he, human encouragement to proceed with iCBT; hw, homework required; iCBT, internet-delivered cognitive–behavioural therapy; is, interpersonal skill training; pe, psychoeducation about depression; pl, placebo effect; ps, problem solving; re, relaxation; rp, relapse prevention; tg, therapeutic guidance for iCBT; w, waiting component.