Examining an entirely self-guided transdiagnostic internet-delivered intervention ‘in the wild’: A randomised controlled trial for anxiety and depression with minimal inclusion criteria

Entirely self-guided transdiagnostic internet-delivered psychological interventions have considerable potential for increasing access to care for adults with anxiety and depression. The current study sought to examine such an intervention under real-world conditions using minimal inclusion and exclusion criteria. Three-hundred and ninety participants were randomised to either an immediate treatment group or a waitlist control group. The intervention consisted of 5 core modules delivered over 8 weeks, according to a structured timetable and with automated emails. Fifty-three percent of participants completed ≥4 of the core modules, and 75 % reported being satisfied with the intervention. At post-treatment, significant improvements were observed in the treatment group compared with control in both anxiety (treatment = 19 % [95 % CI: 12, 26]; control = 8 % [95 % CI: 2, 15]) and depression (treatment = 21 % [95 % CI: 13, 28]; control = 5 % [95 % CI: -1, 12]). These improvements were reflected in significantly greater proportions of participants meeting criteria for clinically meaningful change (≥50 % reduction) in the treatment group for both anxiety (treatment = 25 % [95 % CI: 19, 31]; control = 9 % [95 % CI: 5, 16]) and depression (treatment = 27 % [95 % CI: 20, 36]; control = 8 % [95 % CI: 5, 14]), with numbers needed to treat (NNTs) of 6.6 and 5.3, respectively. The findings of the current study support the potential of entirely self-guided transdiagnostic internet-delivered interventions, particularly for people for whom speaking with a clinician represents a barrier to care, or contexts where the resources for clinician-guided intervention are not available.