Since chronic treatment with antidepressant drugs can reverse stress-induced changes and behaviour and increase adult hippocampal neurogenesis, we continue KRX0401 with a discussion as to whether adult hippocampal neurogenesis can predict antidepressant-induced recovery from stress-induced

changes in behaviour. While many studies have demonstrated that antidepressant treatments increase adult hippocampal neurogenesis (Malberg et al., 2000, Jayatissa et al., 2006 and Santarelli et al., 2003), surprisingly few studies have examined whether antidepressant-induced alterations in neurogenesis can predict whether an individual animal shows behavioural recovery from stress following antidepressant treatment or remains treatment-resistant to the effects of stress. Ablation of adult hippocampal neurogenesis can prevent the ability of some but not all antidepressants to reverse behavioural changes in response to stress (Surget et al., 2011, Perera et al., 2011 and Santarelli et al., 2003), thus suggesting that adult hippocampal neurogenesis

can contribute to antidepressant-induced recovery from stress. However, it is also important to note that buy LEE011 negative findings have also been reported (Surget et al., 2011, Bessa et al., 2009 and David et al., 2009). In parallel, while many studies have demonstrated that chronic treatment with classic monoaminergic antidepressants can reverse stress-induced changes first in depressive-like behaviour (Jayatissa et al., 2006, Bergstrom et al., 2007 and Sanchez et al., 2003), it is also becoming clear that not all animals within the antidepressant-treated group exhibit behavioural recovery from stress, and thus can be stratified into responders or non-responders (Jayatissa et al., 2006 and Christensen et al., 2011). This stratification of

animals in responders and non-responders provides a useful approach to modelling treatment-resistant depression (Christensen et al., 2011 and O’Leary and Cryan, 2013), and can be used to identify the molecular mechanisms that determine successful antidepressant response. Identifying these molecular mechanisms is key towards the development of new and more effective antidepressants (Russo et al., 2012, Hughes, 2012 and O’Leary et al., in press). Although it is clear that adult hippocampal neurogenesis is important for some of the behavioural effects of at least some antidepressants, few studies have investigated whether the rate of neurogenesis in an individual animal directly correlates with its antidepressant-induced behavioural recovery from stress.