A forensic psychologist is conducting a nationwide survey to find out more about stalking. She wants to know who the stalkers are, how common stalking is and what effect it has on victims' lives. And she has a controversial hypothesis she wants to test.

Dr Lorraine Sheridan is conducting a nationwide stalking survey. She's speaking to everyone she can—young and old, stalked and stalkers—about their experience with repetitive following and harassment.

They can be literally anybody—doctors, lawyers, anybody.
— DR LORRAINE SHERIDAN, CURTIN UNIVERSITY

She hopes to use the evidence gathered to lobby for policies that support victims of stalking. 

But she also has a suspicion: that in rare cases, the victims of stalking may become stalkers themselves.

'I reckon that one in a hundred will then become stalkers,' says Sheridan, a lecturer in forensic psychology at Curtin University.

'With certain people, the destruction stalking causes is so great—and the magnitude so enormous—it changes the way they then attach to other people in relationships.'

Much like some victims of abuse, victims of stalking might be more likely to stalk others because they've developed a learned behaviour, Sheridan says.

'They've learned it. It's ingrained within them.'

Sheridan says her hypothesis is based on the hundreds of cases she's reviewed over her 17-year career.

If it proves true, she says, it would serve as another indicator of the profound negative impact of stalking, especially on the young.

The inability to handle rejection

One in four women and one in 15 men will experience stalking in their lifetimes, according to Sheridan.

About half of the time, stalkers have some form of prior romantic relationship with their target, and are often incapable of processing rejection appropriately.

'They just can't handle that somebody doesn't want them—that somebody's turned their back on them and abandoned them,' she says.

'This triggers a rage that just won't go away—an absolute burning to get that person back, and if they can't get them back make them pay for the rejection.'

Stalking or romantic gestures?

Stalkers' behaviour can range wildly—from repeat phone calls and Facebook messages to persistent invitations and unwanted visits, to verbal and physical abuse.

'It's quite a tricky thing to define, because particularly in the early stages a lot of what stalkers do is kind of routine and innocuous if you take each behaviour individually,' Sheridan says.

Stalking is not merely insistent courtship, though, because stalker behaviours involve a persistent threat.

Sheridan says the best working definition is a pattern of intimidating or threatening behaviour that occurs for at least three months.

'It's the repeated and unwanted nature of the intrusions that makes something actually stalking,' she says. 'It's people feeling intimidated, threatened, or live in fear.'

Who is most likely to be a stalker?

Stalkers are often charming, manipulative and attractive, and they often belong to higher socio-economic brackets. Some are mentally ill, but most are not.

'They can be literally anybody,' Sheridan says. 'Doctors, lawyers, anybody.'

More disturbing still is stalkers' inability to identify their behaviour as inappropriate. They typically believes their victims are controlling them, not the other way around.

Although many stalkers can understand how someone else's stalking behaviour is inappropriate, when asked to analyse their own situations they look for justification.

'They cannot recognise it in themselves, but they can recognise it in others,' says Sheridan

How to react

If you think you might be stalking someone, what do you need to do?

'You need to realise that you have a problem with rejection,' Sheridan says. 'As hard as it is, all of us need to let go.'

If you feel like you're being stalked, Sheridan says you should immediately go to the police.

'Just listen to yourself. If you're scared, you have good reason to be,' she says.

'Get to a police station with as much evidence as you can muster. They will take you seriously.'

Professor Lorraine Sheridan currently conducting a study on the rate and effects of stalking in Australia. To participate, take the Curtin University survey here.   

This story originally published on ABC's Radio National here.