The pre-frontal cortex of the brain is responsible for planning, reasoning and, most importantly in consideration to aggression, impulse inhibition. Whether or not a person behaves aggressively may well be a factor of whether or not they are able to successfully resist the urge to be aggressive. Serotonin is implicated in this mechanism as, in normal levels, it seems to have a calming inhibitory effect on neuronal firing in the pre-frontal cortex (Cases, 1995). Therefore, low levels of serotonin may disrupt the calm inhibited firing of neurones, with the result that individuals are less able to resist the impulse to be
