Neuroticism is a personality trait described as an enduring tendency to experience negative
emotional states and to respond poorly to environmental stress. It has been shown that high
neuroticism can predispose, amongst other factors, to the development of depressive episodes.
Recent studies suggest that subjects with high neuroticism have a different response to
stimuli with an emotional content, showing both decreased processing of positive or increased
processing of negative emotionally salient cues. These differences in cognitive processing of
emotional stimuli are believed to underpin the psychological characteristics that link high
neuroticism with a higher risk for depression.
Preliminary data also indicate that modulation of serotonin function by antidepressant
treatment in healthy volunteers with high neuroticism traits could modify the brain activity
associated with the processing of emotional stimuli that is dysfunctional in this vulnerable
population.
The aim of this research is to investigate further whether modulation of serotonin function
via administration of serotonergic antidepressants (SSRIs) can revert the dysfunctional
emotion processing that characterises subjects with the personality trait of high
neuroticism.
In particular we hypothesise that SSRI administration will modify the abnormal patterns in
attention, physiological reactivity and regulation of emotional stimuli present in healthy
individuals with the vulnerable personality trait of high neuroticism.
Carrying out this research on healthy volunteers will enable us to understand if modulating
serotonin function by antidepressant administration has an effect not only on mood symptoms -
as is evident in depressed patients - but also on the predisposing psychological and
cognitive processes that sustain the depressed mood, such as the response to emotional
stimuli. We will also be able to verify if this effect is shown early treatment and prior to
any subjective changes in mood. This will be done by administering seven days of either the
antidepressant citalopram or placebo to subjects with high neuroticism scores and then
comparing them on a series of computer based psychological tests measuring various aspects of
how emotionally salient stimuli are processed.