In second grade I stabbed a kid in the head with a pencil. Whenever I ask my mother if she remembers, her answer is the same: 'Vaguely.'

And I believe her. Because so much about my early childhood is vague. Some things, however, I remember with absolute clarity. I knew as early as seven that something was off. I didn't care about things the way other kids did. Certain emotions – like happiness and anger – came naturally, if somewhat sporadically. 

But social emotions – things like guilt, empathy, remorse and even love – did not. Most of the time, I felt nothing. So I did 'bad' things to make the nothingness go away. It was like a compulsion.

Had you asked me back then, I would have described this compulsion as a pressure, a sort of tension building in my head. It was like mercury slowly rising in an old-fashioned thermometer.

At first it was barely noticeable, just a blip on my otherwise peaceful cognitive radar. But over time it would get stronger. The quickest way to relieve the pressure was to do something undeniably wrong, something I knew would absolutely make anyone else feel one of the emotions I couldn't. So that's what I did.

As a child, I didn't realise there were other options. I didn't know anything about emotion or psychology. I didn't understand that the human brain has evolved to function empathetically, or that the stress of living without natural access to feeling is believed to be one of the causes of compulsive acts of violence and destructive behaviour.