What will those assessing Anders Behring Breivik probably be looking for? His lawyer has suggested that he's insane, and that he was on drugs. But then, he hasn't many alternatives in trying to defend the indefensible.
Drugs might render you calm, but would not enable you to plan so deviously for so long, or to pull off such a complex set of actions so successfully. A psychotic killer would usually be more disorganised, less groomed and usually does not appear so darn satisfied after acting violently.
The degree of mental disturbance
The primary issue will be to decide whether his state of mind, at the time of trial, during the attacks and preceding them, represents a serious degree of mental disturbance, whatever precise diagnosis is made. Whatever diagnosis might eventually be made is essentially irrelevant. It's the degree of impairment that matters.
There are extremists with religious or political views that go far beyond those held by most people, and which absorb them to the exclusion of almost everything else. But they've not lost touch with reality, and would be considered eccentric and obsessed rather than psychotic. They usually would be content to ruminate on their views, rather than to take direct and destructive action to try to implement them.
His claim to be part of a group with other branches, even in Norway, sounds unlikely. He appears to be a typical loner, prickly, narcissist and actually not wanting the company of others. His thoughts as expressed in his manifesto are needlessly complicated, grandiose, and unconvincing, except to himself. We've not heard of him having formed any genuine or lasting personal relationships with anyone, typical of people who commit such atrocities, who tend to be solitary or members of a small group sharing their beliefs. (Remember the Unabomber in America , and the Oklahoma Bomber, Timothy McVeigh).
He was a fantasist, as shown by the pictures he posted of his various costumes, depicting him in various roles he never genuinely held in life, and wearing a range of medals presumably he awarded to himself. His lawyer has said he took some kind of drugs, unspecified, before the attacks, to make himself strong and alert. Perhaps amphetamines. Unlike some jurisdictions, Norway is sensible enough to make it clear that intoxication with any drug taken voluntarily, in no way diminishes one's responsibility for one's deeds.
Back in 1999, the trial of the "Nail Bomber" of London, David Copeland, showed his hatred towards black and gay communities, and he was eventually diagnosed as suffering paranoid schizophrenia. Mentally ill people, including schizophrenics, and even paranoid schizophrenics, are actually very rarely a danger to others rather than to themselves, but this can occur. Only a period of skilled observation and long interviews with Breivik will reveal whether he shows any other of the typical features of such a disorder. There might be a delusional disorder, or a paranoid psychosis.
The fact that he planned and prepared for his addled apocalypse for so many years does not suggest the presence of a severe, incapacitating or progressive psychotic or other illness over this period of time. He doesn't seem to have been impaired in any way, and indeed seems to have outsmarted the local and national police, and was able to shoot and kill for some 90 minutes before he was stopped.
He set up front companies and rented a farm, so he could get the large quantities of fertiliser he needed for his bombs. He may have joined a gun club six years ago to enhance his chances of getting the guns he needed for his task, though it's not yet clear how he obtained his guns and ammunition, but this must have been gradually done.
But it's really not the court's task to find a diagnosis for any clinical reasons. The only legally relevant issue will be whether at the time of preparing for and carrying out the attacks, he was sufficiently mentally impaired as to not be criminally responsible for his acts. On the face of it, and with the information available so far, it appears unlikely that he was thus impaired.
You can hold any daft or incomprehensible views you wish, so long as you can tell right from wrong, and can control your actions so as to avoid doing wrong. His precautions tend to prove that he was well aware that what he was doing was wrong in the view of society and the law, and it's utterly irrelevant whether he considered the actions justified or even necessary. He showed excellent control of his actions and decisions throughout the relevant period. Unless most unexpected evidence turns up, I see it as highly unlikely that he should be found not guilty by reason of insanity. Of course such a verdict might sometimes be considered politically expedient, but that is another matter.
(Professor M.A. Simpson, Health24, August 2011)