I want to add my voice to the chorus encouraging the LW to engage in all out war. Not only that, I endorse the Powell doctrine (as in Colin Powell). Don't be a diplomat - once war is declared the time for diplomacy, for negotiations, is over. Throw everything you have into this and win as fast and definitively as possible. Don't let this be another Iraq - interminable fighting with no distinct gains.

In practical terms: work with your sibling and plan an ambush on Goneril and Lenny. Get the landlord to do everything possible to get them out of there. Visit yourself and threaten them if necessary. Refuse to lend your mother money but have her over to stay for a few months (barring her flat as she leaves).

Your mothers' loneliness is one thing. But the attentions of destructive thieving psychopaths is another, and on this point you have to be very clear.

Once Goneril is frightened of you she'll leave your mother alone. That's the only way to win a psychopaths respect.

They can meet at the mall or the local casino if they want to enjoy each others company - your mum could buy Goneril lunch if she's still feeling like it. But make it clear she's not sponging off your mother for a minute longer.

LW is a deeply conflicted, troubled old fogey in denial about his feelings for this young woman.

Slapping children is controversial, slapping wives is utterly out of bounds these days LW. Furthermore, the fact that you think a slapping is deserved by her indicates sexual feelings for her. This is confusing and upsetting to you, both because you know her parents and you are her superior at work. You feel paternalistic and sexually attracted at the same time. You don't approve of your own feelings towards her and therefore are projecting. ie she must be doing something very bad to be stirring up these very bad feelings in you. Like an angry dad you fantasise about slapping her, which would only heighten the exciting father/lover confusion you're already inappropriately worked up about.

I would advise what I would advise to all fundamentalist/sexist/conflicted men: it's okay to be sexually attracted to a woman. This doesn't mean it's her fault. She no doubt would reject your sexual advances if you were to make your true feelings known. This doesn't mean she's bad and must be punished.

I think you should actively avoid involvement with her in any way before you make a fool of yourself or worse.

Great reply Cary. However, there is an inevitable 'next chapter' to this letter, hypothetically entitled: 'I share an office with a sociopath - what should I do?'

The LWs REAL problem is that sociopaths enjoy 'heat' in relationships, and sharing an office with an ex therapist definitely qualifies as 'hot'. The sociopath is no doubt excited by the possibilities inherent in this situation and will capitalise on them asap. It's no surprise to hear that the sociopath in question has shown no sign of being disturbed so far. He's lying in wait, like a cat at a hole in the wall, waiting for the LW to make a run for it.

Now for the answer: I have no idea. I used to work opposite one. She would have sex with colleagues under my nose. I had to go into therapy to give myself permission to shut my door!

Eventually I got up the courage to call her out on her dismissive behaviour to me in meetings and she became terrified of me as a result. This was an improvement. Then one blissful day I got back to work from holidays and discovered she and her whole team had been sacked, and I was delightfully alone in that long corridor. Hope the same happens for the LW.

People who are uncomfortable make people around them feel uncomfortable - so it's safe to assume she's feeling uncomfortable. I've never heard of the 'laugh so hard it's inappropriate' route to ruthless success. This is making her look like an idiot and no doubt she feels like one too. OR, she's simply oblivious, like the woman with the terrible laugh in Sleepless in Seattle who the Tom Hanks character dated before he met the Meg Ryan character. The audience was set up to hate her with That Laugh.

If I were the LW I would be as reassuring, as grounded, as quiet and sober as possible when dealing with this person. In fact, have the opposite of humour - ask if you have said something unintentionally funny next time she laughs. Play the dead bat approach to see if that can't take some of the wind out of her billowing sails.

I also think it would be doable to have a 'state of the union' chat with her. Ask her how things are going. Is she feeling comfortable etc. Then say that for your part you sometimes are surprised by her laughter. If she has any sensitivity this should be enough.

Otherwise - like Cary says - you can't have someone around you all the time who makes you uncomfortable. She'll have to change or go.

Thinking of which - a woman I went to uni with got really far down the track for a TV journlism apprenticeship. When she didn't get it she asked for feedback and they said 'frankly, it's you personality. We don't like you.'

Now she's a government minister. Makes you think ...