Leah Giarratano.

Leah Giarratano. Photo: Supplied

I've specialised in assessing and treating psychological trauma for the past 17 years. Sadly, one can't work in this area without coming to understand the impact of terrible events upon babies and children - upon developing personalities. Some children will survive such events and go on to live happy, fulfilled lives. Others will develop any of a range of psychiatric disorders, including depression, anxiety and post traumatic stress disorder. And a very small group who are harmed during early childhood will nurture the violence in their minds, fantasising upon it, biding their time, waiting for the opportunity to unleash all of that hate upon others.

The psychopath

I always wanted to meet a psychopath. Until I did.

I spent my doctoral placement in Long Bay Jail, studying inmates with severe personality disorders. It wasn't fun. But at least the experience prompted me to write my first crime novel - Vodka Doesn't Freeze - I used it as a type of catharsis to rid the demons from my mind. Four crime novels later, I've expelled some of the poison, but not so much that my latest book - Disharmony - a young adult, urban fantasy series, doesn't also include a psychopath.

These are some of the questions I am most often asked about psychopaths.

What is a psychopath?

The phrase was coined more than 200 years ago by Dr Philippe Pinel, who described this condition as ''madness without confusion'': these people are not insane. They are not driven by delusions or hallucinations. They know right from wrong. They just don't care. Psychopaths enjoy what the rest of us consider abhorrent and heinous. They recognise the harmful consequences of their acts, but they're incapable of feeling remorse, and concern for the victim is completely absent. They're not immoral; they're amoral.

Nowadays, the official diagnosis for this condition is antisocial personality disorder, although many in forensic settings still use the word psychopath. This is because there are two types of people with antisocial personality disorder: the primary type (emotionally void, deliberate and controlled - the psychopath) and secondary type (acts as a result of poor impulse control and may regret it later; capable of feeling guilt and empathy). Although around 80 per cent of prisoners meet criteria for antisocial personality disorder, only around 30 per cent of men, and up to 1 per cent of women, who meet the diagnosis have the cold and remorseless, predator-type psychopathy.

Are psychopaths born or bred?

For a true psychopath it's both. There is increasing evidence that genetics/biology plays a major role in the creation of psychopaths. Just as illnesses like schizophrenia, alcoholism and even cancer can be inherited, predispositions to violence may also be passed down. In addition, some children seem to be born with lower levels of interpersonal connectivity - they seem from their earliest moments to be less likely to bond, to inter-relate well with others. They're born with reduced empathy. They're highly impulsive and don't consider the consequences of their actions; they are unconcerned about punishment and social approval; and many have lower resting heart rates (making them prone to sensation seeking).

But a child is not born ''evil'' - certain predispositions may be inherited, but our family and society shape the person we ultimately become. A child with these predispositions born to a healthy, loving family may grow up and become a ruthless business leader or a thrill-seeking, elite sportsperson. But if such a child is raised in an abusive home, they may create a monster - a true psychopath. If we look back into the childhoods of a violent psychopath, we find almost invariably a history of physical and/or sexual abuse and neglect.

Do all psychopaths end up

being murderers or rapists?

Not all psychopaths kill or commit crimes. Some of them could be your co-workers or boss. They still go through life wreaking havoc, but of a different type. They will be serially unfaithful; they're emotionally abusive and manipulative; they will take whatever they want without caring at all who they hurt. They lie, won't accept responsibility and are good at getting out of trouble, and persuading others to do what they want. They're also often dominant and arrogant, with an exaggerated sense of their abilities or influence.

And most murderers and rapists aren't psychopaths. Most murders are crimes of passion - committed by people who are angry, jealous, enraged. These people fill our prisons, but when psychopaths kill they do it for fun; because they're bored.

Can psychopaths be

rehabilitated?

The most direct answer is that we have found no cure for an adult psychopath. Unlike almost every other psychiatric disorder, there are no treatment studies that show we can fix this disorder in adulthood.

Medication can control some of the impulsivity, and therapy that helps them to learn to control their actions is attempted, but they will only participate if they see stopping their behaviour as benefiting them. And mostly they don't. They couldn't care less what everyone else wants them to do or not do. They do exactly what they want.

■ Dr Leah Giarratano is a clinical psychologist and best-selling author of four adult crime fiction novels. She is an expert in psychological trauma, sex offences and psychopathology and has had many years assessing psychopaths and treating their victims. Her latest book for young adults, Disharmony: The Telling (Penguin, $19.95), is out now.