‘Cold’ cognition
MDD, neuropsychiatric disorders, OCD
COLD
Our results showed no significant effects on any measures of ‘cold’ cognition, thus contrasting with some of our previous data obtained following acute administration [There are a number of points to note when interpreting the results from the present study. First, it is important to acknowledge the differences between acute and chronic SSRI administration. Previous literature has suggested that neuro-adaptive changes might represent homoeostatic mechanisms by which the brain regulates neurotransmission in response to the drug [Second, the approaches for induction of changes in serotonin vary and this could result in the inconsistent findings. For example, previous studies manipulating serotonin acutely with different methods and using the same PRL task, showed inconsistent results using conventional behavioural measures [One possible limitation of the study was that there was a significant difference in guessing group allocation. However, the escitalopram group were at chance level for guessing group allocation (53% guessing correctly) and over 15% of the placebo group guessed they were on active substance. It is difficult to know how our results on guessing group allocation compares with other studies, as this measure is frequently not reported in the literature. The results are unlikely to have been affected by this, given the lack of cognitive changes and specificity of the effect.Our results, importantly, showed a specific significant effect on reinforcement sensitivity, where escitalopram reduced reinforcement sensitivity, which may in part be explanatory for the blunting effect often reported by patients receiving chronic SSRI treatments. This study also highlights the need for future studies to examine chronic administration of SSRIs beyond 21 days. In addition, future studies should examine the chronic effects of SSRI administration on a similar extensive battery including ‘cold’, and ‘hot’ cognition, particularly reinforcement behaviour in patients with neuropsychiatric disorders such as MDD or OCD.