Police are failing to properly protect victims of stalking, according to a major new report.
Even though maximum jail sentences for stalking are getting longer in England and Wales, police are not fully investigating enough.
"Stalking in itself is not a mental illness," explains Dr Mark Salter from the Royal College of Psychiatrists.
He says a range of treatments are available, but people must first want to help themselves stop stalking.
Dr Salter says stalking is most common among young men who come from difficult backgrounds.
"A lot of young people in that situation, unemployed, using drugs, facing those sorts of pressures, start to form patterns of 'getting even' with the world.
"You resort to those behaviours as a way of communicating your anger and frustration."
Stalking is "a pattern of unwanted, persistent pursuit and intrusive behaviour... that engenders fear and distress in the victim," according to he report from the Inspectorate of Constabulary and the Crown Prosecution Service Inspectorate.
Repeatedly contacting someone, following them, or obsessively watching what they do online are some stalking behaviours.
Dr Salter says it's hard for police and doctors to stop people early in the process.
"They have to want help," he explains, adding that people generally only end up seeing psychiatrists after they have been reported or convicted.
"First of all we look at their lifestyle. We look at the family they come from. We look at their substance misuse - can we help stop that?
"We teach them a variety of breathing and exercise techniques that we know are very effective in anger management."
In more severe cases, people might be prescribed anti-psychotic medicine.
He says anger, resentment, lust and love are all emotions behind stalking.
"They all tend to overlap," he explains. "It's about recognising the emotion and recognising how you can regulate it through changing your behaviour."
Many of us will experience similar emotions at some point, for example when trying to get over an ex.
You might find yourself checking their social media accounts repeatedly. Dr Salter says that is normal and you can learn to control it.
He recommends keeping a diary to monitor your behaviour, and speaking to friends and family.
"You don't need to see a psychiatrist or GP. You have to ask yourself very honestly, 'do you think this is the right thing to do? Is it helping the person who's the unhappy recipient of your attention?"
There is advice available here if you are experiencing stalking