A Personalized Approach to Effects of Affective Bias Modification on Symptom Change and Rumination

This study evaluates the effect of a computerized intervention for depressive symptoms called Affective Bias Modification (ABM). A third of the patients will receive active ABM, a third will receive sham ABM and a third will undergo assessment only. The study will investigate if rumination mediates the effect of the intervention and investigate if specific symptom profiles affect the effect of the intervention.

A main aim of the project is to investigate how the effects of an ABM intervention on depressive symptoms are mediated by transdiagnostic rumination and how characteristics of the symptom network moderate these effects. The Affective Bias Modification Task (ABM) will be applied in a randomized controlled, double blind clinical trial with 6 months follow-up. Personalized networks are generated from prospective assessment of depression-related processes at baseline and follow-ups. Patients (n = 150) will be recruited from out-patient clinics at Diakonhjemmet Hospital, and randomized into one of three conditions: active, sham and assessment only. Patients aged 18-65 with depression (major depressive disorder) or bipolar disorder 2, with or without comorbid anxiety and/or alcohol use disorder will be included. The main hypothesis is that subjects who are in the active ABM group will exhibit less tendency for stress related (state) rumination compared to those in the placebo group. Active vs placebo ABM will decrease depressive symptoms (6 months) and this effect will be mediated by the change in state rumination. Densely connected symptom network and high strength centrality of rumination at baseline will moderate the effect of ABM. By combining mechanisms research with a personalized symptom network approach, this study will be in the forefront of understanding how a drug-free treatment option works and for whom it works best.

In the Affective bias modification (ABM) procedure, paired stimuli (e.g. a negative and a positive facial expression) are presented on a laptop screen, followed by one or two probes (dots) appearing in the spatial location of one of the stimuli. Participants are then required to press one of two buttons as quickly as possible to indicate the number of dots in the probe. Stimuli presentation time is 50% 500 ms and 50 % 1000 ms (evenly distributed throughout the task). In total, the ABM will comprise 90 trials of paired images of faces of different valences. In the active condition, the probe appears at the location of the most positive stimuli of each pair in 87 % of trials (encouraging a positive affective bias). Participants will do ABM in their homes (approx. 5 min.) twice a day for two weeks (28 sessions) using laptop computers provided by us.

In the Affective bias modification (ABM) procedure, paired stimuli (e.g. a negative and a positive facial expression) are presented on a laptop screen, followed by one or two probes (dots) appearing in the spatial location of one of the stimuli. Participants are then required to press one of two buttons as quickly as possible to indicate the number of dots in the probe. Stimuli presentation time is 50% 500 ms and 50 % 1000 ms (evenly distributed throughout the task). In total, the ABM will comprise 90 trials of paired images of faces of different valences. In the sham condition, the probe appears at the location of the most positive stimuli of each pair in 50 % of trials (no contingency between facial expressions shown and the probe location). Participants will do ABM in their homes (approx. 5 min.) twice a day for two weeks (28 sessions) using laptop computers provided by us.

Self-reported depressive symptoms 6 months after the ABM intervention based on a 21-item scale. Each item is scored 0-3 (where scoring description is adapted to each item), yielding a score from 0-63.

Change in self-reported state rumination after stress induction on a 8 item scale. Each item is scored on a 0-100 Visual Analogue Scale, yielding a score from 0-800 will mediate the effect of ABM on depressive symptoms at six months follow up.

Self-reported state rumination after stress induction on a 8 item scale. Each item is scored on a 0-100 Visual Analogue Scale, yielding a score from 0-800.

Less densely connected network of self-reported symptoms and changed centrality of rumination based on a 9-item experience sampling questionnaire administrated five times/day for two periodes of fourteen days. Each item is scored on a 0-100 visual analogue scale.

Network density of self-reported symptoms and centrality of rumination prior to baseline will moderate the effect of ABM, based on a 9-item experience sampling questionnaire administrated five times/day for fourteen days. Each item is scored on a 0-100 visual analogue scale.

Inclusion Criteria: - Current or remitted Major Depressive Disorder, with or without anxiety, with or without alcohol use disorder Exclusion Criteria: Neurological disorder, mania, and/or psychosis.