Can managers have too much of a good thing? Can managers be too clever, or too charming or too courageous? How do you address aggressive behavior in the workplace, the narcissistic manager or anger management in the workplace?

Fact: extremes of anything are, by definition, abnormal. You can be too tall or too slim. It is called the spectrum hypotheses: extremes of good things can be bad things.

Many offices have mugs, plaques or notices which read: “You don’t have to be mad/crazy to work here, but it helps!” We have all seen madness at work: the nasty bully, the arrogant preener and the obsessive tidier. There are control freaks and drunks, Machiavellians and perfectionists, those in need of anger management and the psychopathically corrupt. This book is about them. It is about managerial psychology.

There are three important and surprising things about mental illnesses at work. The first is that, paradoxically, some disorders can actually help people climb the greasy pole though it often “gets them in the end”. The callous, manipulativeness of the psychopath can help in a cut-throat, super-competitive business. The amazing self-confidence of a young, sub-clinically narcissistic manager may really impress those around him in the world of media or fashion. The obsessional may flourish in some sectors to do with checking, monitoring or quality control.

Second, it is surprising that nobody does “select-out” at interviews which is about looking for things you don’t want rather than what you do want. Nobody seems to have the responsibility for trying to identify characteristics/traits/disorders that you really don’t want in managers or colleagues at work. They seem all focused on competencies and things you want. All select in, none select out…and that is why they slip through the net.

Third, it is assumed that you can never have enough of a good thing. You can never be too clever, or charming or courageous. Yet, we know that extremes of anything are, by definition, abnormal. You can be too tall or too slim. It is called the spectrum hypotheses: extremes of good things can be bad things.

The Secrets of Managerial Psychiatry by Professor Adrian Furnham is about a whole range of personality disorders in workplace. It looks at everything from ADHD and passive aggressiveness to the neurotic and impulsive manager. It tries to describe and explain the behavior and help you both understand and deal with these people at work.