Peter Liddle obtained a PhD in physics at Flinders University of South Australia, before qualifying in medicine at Oxford University.

Whilst Head of Psychological Medicine at Hammersmith Hospital, London, in the 1990’s he contributed to the development of non-invasive mapping of human brain activity, including the development of Statistical Parametric Mapping, one of the foundations of modern brain image analysis. 

His current research is concerned with delineating the mental and brain processes that underlie the symptoms of mental disorder. In particular, he employs the techniques of cognitive psychology, functional Magnetic Resonance Imaging (fMRI); and analysis of brain oscillations detected using Electroencephalogram (EEG) and Magnetoencephalography (MEG) to investigate attention, executive function and motivation in healthy individuals and the impairment of these processes in mental disorders, especially in schizophrenia and ADHD.

Throughout his clinical career his major clinical interest has been in the management of psychotic illnesses.