This study is a small-scale randomized controlled trial (RCT) using a 'Leapfrog' design (Blackwell, Woud, Margraf, \& Schönbrodt, 2019) with the aim of investigating feasibility of this design in the context of an RCT of an internet-delivered intervention. The leapfrog design will be applied to a simple cognitive training intervention, imagery cognitive bias modification (imagery CBM), completed over a four-week training period. The trial will start with the three arms described in the initial registration, but these will be removed and new arms added over the course of the trial on the basis of sequential Bayesian analyses.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
188
The imagery cognitive bias modification intervention is derived from that developed via experimental psychopathology research (e.g. Holmes et al., 2009) and adapted for clinical applications in the context of depression (e.g. Blackwell \& Holmes, 2010; Blackwell et al., 2015). The intervention is a series of training sessions in which participants listen to training scenarios consisting of descriptions of everyday situations, structured so that they start ambiguously but always end positively. Participants are instructed to imagine themselves in the situations described as the scenarios unfold. It is hypothesised that via repeatedly practising imagining positive resolutions for ambiguous situations in the training sessions, a bias is trained to automatically imagine positive resolutions for ambiguous situations encountered in daily life.
Ruhr University of Bochum
Bochum, North Rhine-Westphalia, Germany
Dimensional Anhedonia Rating Scale (DARS)
A 17-item scale measuring anhedonia (Rizvi et al., 2015). The primary analysis is a between-groups comparison of post-intervention scores, controlling for baseline scores, using constrained longitudinal data analysis (cLDA). An approximate Bayes factor is then calculated via the t-statistic for the Time x Group effect with a directional default Cauchy prior (rscale parameter = √2/2).
Time frame: Post-intervention (4 weeks post-baseline).
Quick Inventory of Depressive Symptomatology - Self Report (QIDS)
A 15-item version of the QIDS (Rush et al., 2013), excluding the suicidal ideation item, will be used
Time frame: Baseline, 1 week post-baseline, 2 weeks post-baseline, 3 weeks post-baseline, post-intervention (4 weeks post-baseline)
GAD-7
A brief 7-item measure of generalized anxiety symptoms (Spitzer et al., 2006)
Time frame: Baseline, 1 week post-baseline, 2 weeks post-baseline, 3 weeks post-baseline, post-intervention (4 weeks post-baseline)
Positive Mental Health Scale (PMH)
A 9-item questionnaire designed to assess positive mental health (Lukat et al., 2016)
Time frame: Baseline, 1 week post-baseline, 2 weeks post-baseline, 3 weeks post-baseline, post-intervention (4 weeks post-baseline)
Ambiguous Scenarios Test for Depression (AST)
A measure with two 15-item parallel forms designed to assess depression-relevant negative interpretation biases (Rochbacher \& Reinecke, 2014)
Time frame: Baseline and post-intervention (4 weeks post-baseline)
Prospective Imagery Test (PIT)
A measure designed to assess vividness of positive and negative future-oriented imagery (Stöber et al., 2000), here administered with as two 10-item parallel versions (each with 5 positive and 5 negative items).
Time frame: Baseline and post-intervention (4 weeks post-baseline)
Negative Effects Questionnaire - Short Form (NEQ)
A 20-item questionnaire designed to assess potential negative effects of psychological interventions (Rozental et al., 2019)
Time frame: Post-intervention (4 weeks post-baseline)
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