Table 1.

Study characteristics.

Study, authors (publication year)	Study location	Na	Study arms	Delivery mode	Therapeutic rational of TBIb	Length (weeks)	Qualification of the therapists	Degree of guidancec
Andersson et al (2012) [29]	Sweden	88	Email support vs internet program vs waitlist	Stand-alone intervention	CBTd	8	MSc students of clinical psychology	Predominantly therapist administered (email) and predominantly self-help (internet)
Berger et al (2018) [30]	Germany	98	Internet program + F2Fe vs F2F	Blended treatment	CBT	12	Licensed psychotherapists	Predominantly therapist administered
Lindner et al (2014) [31]	Sweden	38	internet program + telephone support vs internet program + email support	Stand-alone intervention	BAf + ACTg	8	MSc students of clinical psychology	Predominantly self-help
Ly et al (2015) [32]	Sweden	93	Smartphone + F2F vs F2F	Blended treatment	BA	9 (blended) and 10 (control)	MSc students of clinical psychology	Predominantly self-help
Meyer et al (2015) [33]	Germany	163	Internet program + TAUh vs TAU + waitlist	Enhanced stand-alone intervention	CBT	13.05	No therapists involved	Self-administered
Steinmann et al (2019) [34]	Germany	59	Telephone + F2F + letters vs telephone + F2F	Stand-alone intervention	CBT	9-13	Licensed psychotherapists	Predominantly therapist administered
Stiles-Shields et al (2014) [35]	USA	325	Telephone vs F2F	Stand-alone intervention	CBT	18	PhD-level psychologists	Predominantly therapist administered
Zwerenz et al (2017) [36]	Germany	229	Internet program + TAU vs active control + TAU	Blended treatment	CBT	12	No therapists involved	Self-administered

^aN: number of participants randomized.

^bTBI: technology-based intervention.

^cBased on the study by Newman et al [37].

^dCBT: cognitive behavioral therapy.

^eF2F: regular face-to-face psychotherapy.

^fBA: behavioral activation.

^gACT: acceptance and commitment therapy.

^hTAU: treatment as usual.