In the last few years there has been a great deal of interest in early intervention in schizophrenia and related disorders generating enthusiasm and hope in both clinicians and the public. In this paper we have defined early intervention in the context of a preventive strategy for schizophrenia and reviewed the most recent evidence regarding the purported relationship between delay in treatment and outcome in schizophrenia and related psychotic disorders, the primary justification for early intervention. We have also reviewed the nature and consequences of delay in treatment, evidence supporting methods to reduce such delays and the role of highly specialized treatment in improving outcome as part of an early intervention strategy. Lastly we have reviewed the current evidence for interventions in the pre-psychotic period and limitations of their application to current practice. We recommend that clinicians should concentrate on providing phase specific treatment early following the onset of psychosis and wait for more definitive evidence regarding the application of interventions in the pre-psychotic phase of the illness.