Narration: Far from getting their comeuppance, in these days of short term goals and high staff turnover, psychopaths often rise to the top. Dr John Clarke: I want people to be aware that they're not going crazy.
In making this story, we spoke to many victims, none who could be identified for fear of defamation or worse - all devastated - all with a similar message. It's the workplace psychopath that's the problem, not them.
Stay too long, and you risk a severe psychological breakdown. Annette: I loved my job but in the end I, I fell apart.
I was just so, so broken and you know, I just walked out and there was no coming back. I just, I can't take another knock like that, Dr John Clarke: When I tell them that one of the options is to leave the company there's shock, and then they go on to how unfair it is but then there's devastation when they do realise that that might be the most appropriate option to take because the situation is not going to change.
Executive: I just can't seem to keep staff and it's all coming from his section. And so if there are huge discrepancies in opinion that's reason to start delving deeper. Here are the final two: Is your boss opportunistic, ruthless, hating to lose and playing to win?
Dr John Clarke: There are 20 characteristics to define a psychopath. Three different people have told me that with your capabilities you could step straight out of a support role into top management. They're so good at saying things you want to hear to your face at the same time they're knifing you in the back. Narration: Annette's boss was typical - charming his superiors and acolytes, while isolating and undermining his victims.
Narration: There's a growing realisation psychopaths are thriving in today's workplace. Now the figures are that 0.5% of women are psychopaths, and 2% are men. And how do you avoid being the next victim of the workplace psychopath.
According to the textbooks, every large company has them. So that means there are up to 25 corporate psychopaths somewhere up there. Psychologist John Clarke started out profiling criminal psychopaths, but four years ago, he began to realise there was a much bigger problem.
Research is showing they're deficient in a crucial skill that evolved to ensure we don't abandon our friends and family - empathy.
Dr John Clarke: Empathy really is the ability to feel what another person is feeling. This lack of emotional response extends deep into the brain.