In the opera house it can sometimes seem but a short step from melody to malady, and then on to madness; and, indeed, from there to murder, melancholy and mourning. One might argue that of all the art forms, it is opera that has, since its conception, been most frequently dependent on narratives of suffering, sickness and death.

The formal complexity of opera – combining words, music and stagecraft – is equalled by the multifaceted nature of its audience's experience: aural, visual and kinetic elements fuse to communicate narrative, drama and emotion. Opera is a comprehensive, embracing theatrical event of great intensity and immediacy; it is a world of extremes. And, as such, it is a form that seems peculiarly suited to the portrayal of acute emotional and behavioural disturbance. Thus, it is perhaps not surprising that its stage is so often populated by precarious individuals whose feelings and actions seem to be embellishments, magnifications and even distortions of ‘normal’ human behaviour. Through the presentation, direct or indirect, of nonconformist, even transgressive, views and experiences, opera asks questions of its audience, forcing them to interrogate their own actions, beliefs and judgements.

Opera inevitably engages with social, intellectual, cultural and moral concerns. So, it seems fitting to ask how we would relate to such troubled, unpredictable individuals were we to encounter them in our everyday lives. How would we judge them and their actions? Certainly, they are frequently ‘dangerous to know’, but are they ‘mad’, or just ‘bad’? Are they simply ‘evil’, or are they responsible for their actions – and if so, should they be punished? And, does the overwhelming sensory effect of opera shape our intellectual and emotional response to such individuals when we see them on stage?

The ‘mad or bad’ debate roils across the fields of criminology, law, psychology, philosophy, sociology and neuroscience. And it is a debate which engages and exercises us all; thus, feeding the anxieties of a society which is, perhaps understandably, frightened of mental illness, journalists often seem to relish the more salacious details when reporting cases and crimes committed by such unstable, tormented individuals. More soberly, the justice system aims to distinguish between those who are ‘mad’ – insane, not criminally responsible, and suffering from a medical disorder – and those who are ‘bad’ – lacking empathy, guilt and remorse, and essentially suffering from a moral disorder.