The mental illness spectrum.

There exists a growing argument in favour of a more dimensional approach to the diagnosis and treatment of psychiatric patients. This encompasses first the idea of a spectrum of symptoms correlating to severity within a single disorder, and secondly, the idea of spectra of different disorders sharing overlapping collections of symptoms. Here we consider the issue in light of specific clinical examples we have observed, which support the idea of a 'mental illness spectrum', both with symptoms within a single disorder, and between different mental disorders.