53 Conclusions Psychopathy is a serious developmental disorder marked by pronounced emotional dysfunction and an increased risk for aggression. It is not equivalent to antisocial personality disorder from DSM-IV-R. Individuals meeting criteria

for psychopathy with gold standard assessment techniques will also meet criteria for antisocial personality disorder. However, many other individuals with antisocial personality disorder will not meet criteria for psychopathy.59 It is argued here that the emotion Inhibitors,research,lifescience,medical dysfunction relates to three core functional impairments: in the association of stimuli with reinforcement, the representation of expected value information and in prediction error signaling. These find more impairments are thought to relate to the observed dysfunction seen in both sMRI and fMRI studies within the amygdala, vmPFC, Inhibitors,research,lifescience,medical and (currently only in work with youth samples) striatum. Other regions of temporal cortex (temporal pole and superior

temporal sulcus) may also be dysfunctional—though whether this reflects primary pathology or the secondary, developmental impact of dysfunction in the core regions is unclear. It is also unclear whether any functions reliant on these regions are detrimentally affected in individuals with psychopathy. Finally, there is sMRI and fMRI evidence of posterior cingulate Inhibitors,research,lifescience,medical cortex dysfunction. This is interesting given the extensive connectivity

of this region with vmPFC and also Inhibitors,research,lifescience,medical its shared overlap in function. Both regions are implicated in the representation of expected value.79 However, as yet, no studies have formally investigated the representation of expected value within posterior cingulate cortex in adults with psychopathy. Importantly, by specifying the computational Inhibitors,research,lifescience,medical and neural systems level impairments that are associated with this disorder, we now have available biomarkers of dysfunction. Such biomarkers are not only of potential use in diagnostic classification—the functional impairments in one aggressive patient may be very different from those of another—but also for assessing treatment efficacy. Currently, this disorder is regarded as extremely difficult to treat. Moreover, treatment studies are difficult when the outcome measure may be of reoffending or incidence of aggressive episodes. However, with appropriate biomarkers it becomes possible to use these to determine treatment efficacy. The field is currently at this exciting stage. Now we need to identify effective treatments. Acknowledgments The author reports no competing interests. This work was supported by the Intramural Research Program of the National Institute of Mental Health, National Institutes of Health under grant number 1-ZIA-MH002860-08.