The aim of this paper is to describe a schizotypy scale, the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), and its use in psychiatry. Schizotypy is a biologically determined personality phenomenon. Schizotypal disorder, as a diagnostic category in contemporary psychiatric classifications, has been included in schizophrenia spectrum disorders. This may reflect similarities in neurobiological and neuropsychological features between persons with schizotypy and patients with schizophrenia. However, schizotypal traits are also more marked in bipolar disorder (BD) compared with those in healthy subjects. The O-LIFE was created by Claridge and his co-workers and consists of four dimensions: unusual experiences, cognitive disorganisation, introvertive anhedonia and impulsive nonconformity. Studies using O-LIFE in psychiatry, demonstrated a number of associations between the dimensions of the O-LIFE and the clinical features of schizophrenia, in mood disorders and in healthy persons. In patients with BD treated with lithium carbonate, worse effects of lithium were observed in subjects with high scores on the O-LIFE dimensions (particularly cognitive disorganisation). Recently, some molecular-genetic associations have also been shown between O-LIFE dimensions and polymorphisms of the dopaminergic system and circadian rhythm genes.