People who have epilepsy seem particularly liable to certain major psychiatric disorders: a chronic interictal psychosis that closely resembles schizophrenia; and episodic psychotic states, some of which may arise in close temporal relation with seizure activity. These disorders are conventionally referred to as the psychoses of epilepsy although some of the episodic forms would be more accurately described as acute confusional states. These conditions have for long puzzled and intrigued psychiatrists and neurologists, but in recent years this interest has quickened especially among biologically minded psychiatrists in search of a neurological model for schizophrenia. In the psychoses of epilepsy and in schizophrenia converging lines of enquiry, in neuroimaging and in neuropathology in particular, have implicated the mesial temporal structures, the more so in the dominant hemisphere, and comparable abnormalities have been reported. This review will seek to identify areas of progress, areas of diYculty, and persisting dilemmas.