Fronto-temporal dementia (FD) is a clinical syndrome caused by degeneration of the frontal lobe of the brain. Researchers from the University of Melbourne thought that people with FD were often diagnosed with schizophrenia or bipolar disorder before the real cause of their problem became apparent. They reviewed the cases of 17 people with FD and found that four of them had initially been diagnosed with pyschosis and one with bipolar disorder. These diagnoses had been given, on average, five years before they were found to be suffering from FD. A third of patients aged 30 and under and a quarter of those aged 40 and under had initially been diagnosed with psychosis.
Velakoulis, D. ... [et al] - Frontotemporal dementia presenting as schizophrenia-like psychosis in young people: clinicopathological series and review of cases British Journal of Psychiatry April 2009, 194(4), 298-305