This is a video that I never get tired of watching, and I've watched it many
times. Before we get too deep into "blaming biology" for our quirks, here are
some things to think about. How quirky does our behavior have to be before it
is a disease or disorder rather than just the extreme end of a continuum of
normal behavior? If our behavior changes after a change (damage, disease) in
the brain, how small can that change in the brain be and still result in
"disordered behavior"? If we strike and injure someone while having an
epileptic convulsion, who is at fault? What if we push someone off a rooftop
while in the throes of paranoid delusions? What if we suddenly begin cursing
(or barking or quacking) at everyone we see after suffering a high fever due
to a streptococcal infection?

Robert Sapolsky on Individual Differences 
https://www.youtube.com/watch?v=-PpDq1WUtAw

I. the line between the essence of a person and his/her disease or disorder

    A. epilepsy - is an epileptic criminally liable for striking someone
       while he's having a convulsion?
    B. schizophrenia - how much of their behavior are schizophrenic people
       responsible for?
    C. learning disorders - vs. stupidity and laziness
    D. John Hinckley (who attempted to assassinate President Reagan, in case
       you don't remember) - did he "get away with it"?

II. disorder vs. extreme end of a continuum of normal behavior

III. the person sitting next to you does not have the same frontal cortex
     that you do

    A. individual differences
    B. frontal lobe and disinhibition
    C. Huntington's disease and disinhibition
        1. initially a disease of frontal cortex
        2. sexual promiscuity and reproductive success
        3. is this a "disease" or an evolutionary innovation that increases
           reproductive fitness?
    D. Tourette's disease
    E. PANDAS - neuroendocrine disease associated with streptococcal infection
        1. breakdown of blood-brain barrier
        2. autoimmune disorder in the brain
        3. similar to Tourettes with strange tics and so forth
        4. treated with immunosuppressant drugs
    F. obsessive-compulsive disorder
        1. related to high fever and strep infections
        2. genetic contribution
        3. increased metabolic rate in the basal ganglia
        4. is this "neurological" or "psychological"? - all behavior has some
           sort of underpinning in the brain, after all

IV. are these syndromes neurological or psychiatric?

    A. Jerusalem syndrome
    B. Stendhal's syndrome (or Florence syndrome)
    C. trichotillomania (compulsive hair pulling) with trichophagia (hair eating)
    D. apotemnophilia - obsessive desire to have a limb removed by amputation
    E. acrotomophilia - obsessive desire to have sex with amputees
        (note: he gets these last two backwards in the video)
    F. one case of obsession with polka music after a person had a small stroke
       in the frontal lobe

V. difference between neuropsychiatric disease and individual differences

    A. regular or ritualistic behaviors vs. compulsions - I have to count the
       number of beeps my thermometer makes while I'm taking my temperture, and
       if I'm distracted and lose count, I become (mildly) upset; is that a
       compulsion?
    B. we all have milder elements of behavior that in a more severe form would
       be considered a "disease" - is that because we have milder forms of the
       brain alterations that result in the disease? (probably)
    C. there but for the grace of God and a few glutamate receptors in the
       frontal lobe go I
    D. explaining these things biologically is a challenge to our sense of
       individuality and uniqueness _ what happens once we explain "everything"?
    E. social issues
    F. if you become a doctor or a counselor, you will someday be making decisions
       that have profound effects on other people's lives, and those decisions
       will sometimes be based on inadequate information or knowledge about the
       person's condition
    G. does being healthy mean we have the same diseases as everyone else does?

VI. "Now even physics knows sin." - Robert Oppenheimer