Table 1.
Characteristics of studies included in the meta‐analysis
| Study (year) | Participants | Mean age (range) | Intervention (n) | Control (n) | Intervention duration weeks/number of modules | Country | Support | Outcomes | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Anxiety | Depression | Impaired functioning | Quality of life | Worry | ||||||||
| G. Andersson et al. (2012) | General population, self‐referral, telephone‐administered SCID‐I diagnosis | 44.4 (22–66) | Multi‐arm trial: Disorder‐specific iCBT (27) | Wait‐list (27) | 8/8 | Sweden | iCBT: CBT trained therapists (two licensed psychologists and three final year psychology students) | GAD‐IV | BDI‐II | ‐ | QOLI | PSWQ |
| Disorder‐specific iPDT (27) | iPDT: Psychodynamically trained therapists (three final year clinical psychology students, one licensed psychologist) | |||||||||||
| E. Andersson et al. (2017)a | General population, self‐referral, telephone‐administered MINI diagnosis | 32.5 (18+) | Transdiagnostic IbET (70) | Wait‐list (70) | 10/8 | Sweden | Therapists (final year clinical psychology students and licensed psychologists) | HAD‐A | MADRS‐S | ‐ | BBQ | PSWQ |
| Bell et al. (2012) | Secondary care service users, recruited from service wait‐list, in‐person‐administered SCID‐I diagnosis | 33.6 (18–65) | Disorder‐specific cCBT (6) | Wait‐list (7) | 12/4 | New Zealand | Research assistants | GADI | BDI‐II | WSAS | ‐ | PSWQ |
| Berger et al. (2014) | General population, self‐referral, telephone‐administered SCID‐I diagnosis | 35.1 (18–65) | Multi‐arm trial: Transdiagnostic tailored Internet‐delivered guided self‐help (10) | Wait‐list (12) | 8/8 | Switzerland, Germany, Austria | Minimal therapist guidance (five final year clinical psychology students, one clinical psychologist, one CBT therapist) | BAI | BDI‐II | ‐ | ‐ | PSWQ |
| Standard disorder‐specific Internet‐delivered guided self‐help (11) | ||||||||||||
| Christensen et al. (2014) | General population, self‐referral, telephone‐administered MINI diagnosis | 25.5 (18–30) | Disorder‐specific online e‐health iCBT (8) | Online attention placebo (7) | 10/10 | Australia | Clinical psychologists and GPs | GAD‐7 | CES‐D | ‐ | ‐ | ‐ |
| Dahlin et al. (2016) | General population, self‐referral, telephone‐administered SCID‐I diagnosis | 39.48 (18+) | Disorder‐specific Internet‐delivered acceptance‐based behavior therapy (52) | Wait‐list (51) | 9/7 | Sweden | Clinical psychologists | GAD‐7 | PHQ‐9 | ‐ | QOLI | PSWQ |
| Dear et al. (2015) | Older general population, self‐referral, telephone‐administered MINI diagnosis | 65.45 (61–81) | Transdiagnostic anxiety and stress‐directed iCBT (16) | Wait‐list (23) | 8/5 | Australia | Clinical psychologist | GAD‐7 | PHQ‐9 | ‐ | EQ‐5D‐5L | ‐ |
| Hirsch et al. (2018) | General population, self‐referral, telephone‐administered SCID‐I diagnosis | 30.59 (18–65) | Multi‐arm trial: Transdiagnostic iCBM‐I (44) | Placebo iCBM‐I (20) | 4/10 | The United Kingdom | Researchers | GAD‐7 | PHQ‐9 | ‐ | ‐ | PSWQ |
| Johansson et al. (2013) | General population, self‐referral, telephone‐administered MINI diagnosis | 44.9 (19–77) | Transdiagnostic Internet ‐delivered APT (23) | Therapist supported wait‐list (26) | 10/8 | Sweden | Therapists (final year clinical psychology students) | GAD‐7 | PHQ‐9 | ‐ | ‐ | ‐ |
| L. Johnston et al. (2011) | General population, self‐referral, telephone‐administered MINI diagnosis | 41.62 (19–79) | Multi‐arm trial: Transdiagnostic clinician‐assisted iCBT (21) | Wait‐list (20) | 10/8 | Australia | Clinician: clinical psychologist | GAD‐7 | PHQ‐9 | SDS | ‐ | PSWQ |
| Coach‐assisted iCBT (18) | Coach: registered psychologist without specialist training | |||||||||||
| Jones et al. (2016) | Older general population, self‐referral, telephone‐administered MINI diagnosis | 65.15 (60+) | Transdiagnostic iCBT (24) | Wait‐list (22) | 7–10/7 | Canada | Therapist | GAD‐7 | PHQ‐9 | ‐ | WHOQOL‐BREF | PSWQ‐A |
| Mullin et al. (2015) | University students, self‐referral, telephone‐administered MINI diagnosis | 27.7 (19–55) | Transdiagnostic iCBT (27) | Wait‐list (13) | 5–6/3–6 | Australia | Therapist (clinical psychology doctoral student) | GAD‐7 | PHQ‐9 | SDS | ‐ | ‐ |
| Newby et al. (2013)a | Wait‐list service users, self‐referral, telephone‐administered MINI diagnosis | 44.25 (18+) | Transdiagnostic iCBT (46) | Wait‐list (54) | 10/6 | Australia | Clinician and therapist | GAD‐7 | PHQ‐9 | WHODAS‐II | ‐ | PSWQ |
| Paxling et al. (2011) | General population, self‐referral, telephone‐administered SCID‐I diagnosis | 39.3 (18–66) | Transdiagnostic iCBT (44) | Wait‐list (45) | 8/8 | Sweden | Therapists (final year psychology students and clinician) | GAD‐IV | MADRS‐S | ‐ | QOLI | PSWQ |
| Richards et al. (2020) | Stepped care service users, routine care referral, PWP‐administered MINI diagnosis | 33 (18–80) | Transdiagnostic iCBT (134) | Wait‐list (65) | 8/7 | The United Kingdom | PWPs (psychology graduates trained in CBT) | GAD‐7 | PHQ‐9 | WSAS | EQ‐5D‐5L | ‐ |
| Robinson et al. (2010) | General population, self‐referral, telephone‐administered MINI diagnosis | 46.96 (18–80) | Multi‐arm trial: Disorder‐specific iCBT clinician‐assisted (50) | Wait‐list (48) | 10/6 | Australia | Clinician: clinical psychologist. Technician: clinical manager administrative role at the clinic | GAD‐7 | PHQ‐9 | SDS | ‐ | PSWQ |
| Technician‐assisted (47) | ||||||||||||
| Salemink et al. (2014) | Secondary care service users, recruited from service wait‐list, telephone‐administered SCID‐I diagnosis | 40.25 (18+) | Transdiagnostic iCBM‐I (11) | Placebo iCBM‐I (7) | 1.6/8 | The Netherlands | Unsupported | STAI‐T | BDI | ‐ | ‐ | ‐ |
| Titov et al. (2010) | General population, self‐referral, telephone‐administered MINI diagnosis | 39.5 (18–74) | Transdiagnostic iCBT (18) | Wait‐list (16) | 8/6 | Australia | Clinical psychologists | GAD‐7 | PHQ‐9 | SDS | ‐ | PSWQ |
| Titov et al. (2011) | General population, self‐referral, telephone‐administered MINI diagnosis | 43.9 (18–79) | Transdiagnostic iCBT (9) | Wait‐list (12) | 10/8 | Australia | Clinical psychologist | GAD‐7 | PHQ‐9 | SDS | ‐ | PSWQ |
| Titov et al. (2009) | General population, self‐referral, telephone‐administered MINI diagnosis | 44 (18+) | Disorder‐specific iCBT (24) | Wait‐list (21) | 9/6 | Australia | Clinical psychologist | GAD‐7 | PHQ‐9 | SDS | ‐ | PSWQ |
Abbreviations: APT, affect‐phobia therapy; BAI, Beck Anxiety Inventory; BBQ, Brunnsviken Brief Quality of Life Questionnaire; BDI‐II, Beck Depression Inventory‐II; cCBT, computerized cognitive behavioral therapy; CES‐D, Centre for Epidemiological Studies Depression Scale; EQ‐5D‐5L, EuroQol–5 Dimensions–5 Levels; GAD‐IV, Generalized Anxiety Questionnaire‐IV; GAD‐7, Generalized Anxiety Questionnaire‐7 item; HAD‐A, Hospital Anxiety and Depression Scale‐Anxiety; HAD‐D, Hospital Anxiety and Depression Scale‐Depression; IbET, Internet‐based extinction therapy; iCBM‐I, Internet‐based cognitive bias modification for interpretations; iCBT, Internet‐delivered cognitive behavioral therapy; iPDT, Internet‐delivered psychodynamic therapy; MADRS‐S, Montgomery‐Asberg Depression Scale; MINI, Mini International Neuropsychiatric Interview; PHQ‐9, Patient Health Questionnaire–9 item; PSWQ, Penn State Worry Questionnaire; PSQW‐A, Penn State Worry Questionnaire‐Abbreviated; PWP, psychological well‐being practitioners; QOLI, Quality of Life Inventory; SCID‐I, Structured Clinical Interview for DSM‐4 Axis I Disorders; SDS, Sheehan Disability Scale; STAI‐T, State‐Trait Anxiety Inventory‐Trait; WHODAS‐II, World Health Organization disability assessment schedule II; WHOQOL‐BREF, World Health Organization Quality of Life Instrument; WSAS, Work and Social Adjustment Scale.
These two studies included a minority of participants with significant subthreshold symptoms of GAD.