‘I can’t believe it was him.’

‘He seemed like such a normal person.’

‘Everyone on this street liked him so much.’

‘He was always so polite and nice to everyone.’

Those were just some of the comments made by friends and neighbors of infamous serial killers such as Jeffrey Dahmer, Ted Bundy, John Wayne Gacy, and Dennis Rader (the BTK Killer). And the reasons behind such remarks are simple.

Psychopaths, viewed by many psychiatrists as “society’s most dangerous individuals”, don’t act or look crazy. They’re not mentally ill. They don’t suffer seizures, blackouts, or lose track of reality due to their condition. In fact, they’re not only masters at appearing normal to everyone around them, they’re also experts at gaining people’s trust.

Now allow me explain why that is.

A Psychopath’s main characteristic is what psychologists call “severe emotional detachment”, or SED for short. SED is one of the hardest “mental abnormalities” to diagnose - harder than schizophrenia, bipolar disorder, psychosis and even borderline personality disorder, but what does SED really mean?