Central nervous system infections can cause both acute and chronic presentations with neuropsychiatric symptoms. Acute CNS infections, such as encephalitis not infrequently have behavioural disturbances as part of the presenting syndrome, and indeed some patients are initially thought to have psychiatric illness. Other infections that have more insidious presentations, such as tuberculous meningitis, may initially present as a dementing illness. In this talk some of the more common CNS infections that present with neuropsychiatric disease will be considered through a series of interactive case presentations; in addition there will be one or two two rarities for reference. Some of the key red flags that should make one consider infection will be highlighted, as well as essential early steps in patient management. In addition the latest relevent research from the www.BrainInfectionsUK.org portfolio will be presented, along with pertinent studies from elsewhere.