Schizophrenia remains one of the most common psychiatric disorders, affecting approximately 1% of the world's population. It occurs with a similar frequency in all races and cultures, and while men and women are equally likely to be affected by schizophrenia, its age of onset is earlier and its severity is greater in men. If left untreated, schizophrenia is almost always a lifelong, disabling disease.
Despite the seriousness of this disease, over the past decade we have witnessed major advances in our understanding of schizophrenia and our ability to mitigate its disabling effects. Systematic diagnosis based on well-defined symptom categories has become a worldwide standard. An increased number of symptom categories are now recognized as being central to schizophrenia, including psychotic symptoms, symptoms of thought disorganization, negative symptoms, and mood instability. In addition, subtle deficits in fundamental elements of cognition, such as attention and memory, have been identified in patients with schizophrenia. These deficits, which may predate the onset of more obvious clinical symptoms, appear to be the major block to patients' attempts to return to school or work.
The recognition of new symptom categories and cognitive deficits in schizophrenia patients offers important new avenues for treatment.