This study will assess learning bias (the tendency to learn more from negative relative to positive outcomes) at baseline in 3 groups of participants (currently depressed, previously depressed and never depressed). It will then try to modify this bias using a simple computerised training task completed at home daily for 2 weeks. Outcome measures include symptoms of depression, cognitive measures (i.e. accuracy and reaction time during completion of tasks), pupillometry measures and salivary cortisol.
Depressed patients tend to focus on negative, at the expense of positive, events. This bias of attention is thought to be one factor which causes some people to be at higher risk of developing depression. One reason depressed people might pay more attention to negative events is that they think those events are more useful to them when they learn about the future. In this study the investigators will compare the learning styles (i.e. whether participants focus more on negative or positive information when learning about the future), cognitive biases and salivary cortisol levels (the levels of the hormone cortisol can be measured in the saliva and is known to be raised in those at risk of depression) of currently depressed (N=40), previously depressed (N=40) and never depressed (N=40) participants. The study will then randomly assign participants to complete one of two version of a learning task daily over two weeks. One version of the task will be designed to encourage an optimistic learning style, whereas the other will encourage neither an optimistic nor pessimistic learning style. The study will then retest participants' learning styles, cognitive biases, salivary cortisol and mood (using questionnaire measures) after completion of the task and again after 1 month. Study activities for participants will be: Screening visit (1 hours), baseline test visit (2 hours), task completion at home (10 mins per day for 2 weeks), test visit 2 (2 hours, completed 2 weeks after baseline visit) and test visit 3 (2 hours, completed 1 month after test visit 2). Participants will be asked to collect saliva samples, to measure cortisol, immediately after they wake up on the 3 testing days. Note that testing sessions involve pupillometry (measurement of area of pupil of the eye). This is done using a specialised camera pointed at the eye and is not invasive.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
120
Information bias learning task-- a computer based task in which positive information is more useful when learning how best to complete it
A control version of the IBLT task-- a computer based task in which both positive and negative information is useful when learning how to complete it
Dept of Psychiatry, University of Oxford
Oxford, Oxfordshire, United Kingdom
Quick Inventory of Depressive Symptoms (self report, 16 item)
Standard questionnaire measure of depressive symptoms
Time frame: change between baseline and week 6
Quick Inventory of Depressive Symptoms (self report, 16 item)
standard questionnaire measure of depressive symptoms
Time frame: change between baseline and week 2
Montgomery Asberg Depression Rating Scale
Standard clinical rating scale for depression
Time frame: change from baseline to week 2 and 6
Learning parameters from information bias assessment task
Derived parameters from a computer based learning task (tests process presumed to be altered by IBLT-- information bias learning task-- intervention)
Time frame: baseline to weeks 2 and 6
Salivary cortisol concentration
Samples collected on waking
Time frame: baseline to weeks 2 and 6
Learning parameters derived from pupillometry data
Parameters are derived from regression of pupil size data collected during the information bias assessment task
Time frame: baseline to weeks 2 and 6
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