The ETB is an efficacy biomarker to detect and investigate the antidepressant action of novel compounds. The ETB is based on the hypothesis that antidepressants may work by reversing negative biases in depression prior to changes in mood.
The ETB is a set of emotion-related experimental paradigms. These paradigms are designed to measure biases in emotional processing that are thought to be core components of depression. Each paradigm has been shown to be sensitive to conventional antidepressant treatment. Early effects of antidepressants on emotional processing may contribute to later changes in mood and symptoms.
The ETB comprises five cognitive tests related to emotional processing. Performance on the tasks included in the ETB is altered in people who are depressed, or who are at high risk of becoming depressed. The rationale is that the tests measure negative bias that the participating individual is unaware of, which may decrease or eliminate the placebo effect observed with traditional scales used to measure depression, e.g. Beck Depression Inventory or Hamilton Depression rating scale. These tasks are therefore useful in the early stages of drug development of novel antidepressant agents. Completion time is in the range 90-120 minutes.