‘Multidimensionally impaired syndrome’ and schizotypal personality disorder ‘Multidimensionally impaired syndrome’  (MDI)  is a term coined to describe children who have brief transient psychotic symptoms, emotional lability, poor interpersonal skills, normal social skills and multiple deficits in information processing (Gordon et al. 1994). The diagnostic status of this group remains to be resolved. Short-term follow-up suggests that they do not develop full-blown schizophrenic psychosis. However, they have an increased risk of schizophrenia-spectrum disorders among first-degree relatives and the neurobiological findings (e.g. brain morphology) are similar to those in childhood onset schizophrenia (Kumra et al. 1998c). This group may possibly represent a genetically high-risk phenotype for schizophrenia rather than a prodromal state. Children with schizotypal personality disorder (SPD) lie on a phenotypic continuum with schizophrenia and have similar cognitive and social impairments and are prone to magical thinking, mood disturbances and non-psychotic perceptual disturbances. Distinction from the prodromal phase of schizophrenia is particularly difficult when there is a history of social and academic decline without clear-cut or persisting psychotic symptoms. It has been reported that negative symptoms and attention in SPD improve with a low dose of risperidone (0.25 - 2.0 mg) (Rossi et al. 1997). Epilepsy Psychotic symptoms can occur in temporal and frontal lobe partial seizures. A careful history is usually sufficient to reveal an aura followed by clouding of consciousness and the sudden onset of brief ictal psychotic phenomena often accompanied by anxiety, fear, derealization or depersonalization. However, longer lasting psychoses associated with epilepsy can occur in clear consciousness during postictal or interictal periods (Sachdev 1998).  In epileptic psychoses,  hallucinations,  disorganized behaviour and persecutory delusions predominate, while negative symptoms are rare.  Children with complex partial seizures also have increased illogical thinking and use fewer linguistic-cohesive devices which can resemble formal thought disorder (Caplan et al. 1992). A positron emission tomography (PET) study has shown hypoperfusion in the frontal, temporal and basal ganglia in psychotic patients with epilepsy compared with non-psychotic epileptic patients (Gallhofer et al. 1985). Epilepsy and schizophrenia may co-occur in the same individual, so that the diagnoses are not mutually exclusive. The onset of epilepsy almost always precedes psychosis unless seizures are secondary to antipsychotic medication. In a long-term followup of 100 children with temporal lobe epilepsy, 10% developed schizophrenia in adult life (Lindsay et al. 1979). An EEG should be performed if a seizure disorder is considered in the differential diagnosis or arises as a side-effect of antipsychotic treatment.  Ambulatory EEG monitoring and telemetry with event recording may be required if the diagnosis remains in doubt.