Symptom relief and facilitation of emotional processing.

Symptoms and observable signs offer an important way of measuring the severity of depression and estimating recovery. However, a shift to understanding the cognitive neuroscience underlying the clinical picture has been fruitful and could change the approach in meaningful ways. Cognition as defined by attention, memory and executive function is impaired in depression and offers a way of identifying abnormal brain states or structure. Moreover, such changes may limit functional recovery and explain why recurrent depression in particular is so impairing. More subtle aspects of cognition can be revealed by studies of emotional processing. Patients with depression have negative emotional biases but the measurement of such effects is confounded by the global impairments already described and may be secondary to a primary change in mood. Nevertheless, there are early effects of antidepressants treatments in healthy volunteers and depressed patients on such mechanisms specifically. It remains to be established how far the properties of antidepressants are defined by such effects both in relation to successful treatment and in their potential for emotional side effects, or blunting of experience, after recovery from depressive symptoms.