This is a summary of a lecture given on 21 Oct 2006 to psychiatrists attending a half-day seminar sponsored by the Evolutionary Psychiatry Special Interest Group,  St John of God Health Services, AstraZeneca and Wyeth. 
I updated some of the terminology and wrote the Abstract in June 2007.  
A Usable Evolutionary Classification System for Mental Disorders

Contents

Abstract

The paradigmatic failure of psychiatry

Benefits of an evolutionary approach

Does evolutionary psychology have any answers?

…Evolutionary psychiatry?

Unveiling an evolved BPS model…

Test-driving some DSM disorders through the model

Abstract

Aims          It is proposed that incorporating evolutionary models of mental order and disorder is essential to an upgraded psychiatric classificatory system, to bridge the gaps left by DSM, the four standard methods explaining mental disorders implicit in contemporary psychiatry (disease, dimensional, behavioural and life-story perspectives) and the biopsychosocial (BPS) model.  Evolutionary models examine ‘why’ we are susceptible to developing maladaptive mental and behavioural phenomena, rather than focusing on ‘what’ has gone wrong and ‘how’, and thus avoid reductionism and over-simplification. 

Methods        Deficiencies in the existing models (DSM and the biopsychosocial) are revealed.  Evolutionary models of mental disorder proposed by evolutionary psychologists and psychiatrists are examined.  Then an evolutionarily-based classificatory system is unveiled, which aims to be a pragmatic upgrade to the biopsychosocial model: “The Malfunction - Dysregulation - Asocialisation (MDA) Model”.  Disorders of Malfunction result from localised or non-localised cerebral dysconnectivity due to genetic vulnerability and/or injuries of the developing central nervous system. Disorders of Dysregulation result from dysregulation of normal brain mechanisms leading to failure to achieve specific biosocial goals of the entire organism.  Disorders of Sociability are characterised by behaviours that are deviant from the individual's community but are adaptive for their genes.  Natural Selection is argued to have equipped homo sapiens with lifespan-specific archetypal propensities to navigate biosocial imperatives that facilitate inclusive fitness.  Organism-specific archetypal disruption is grouped alongside the three general evolutionary explanations to increase specificity by identifying functional impairment caused by the disorder.  Some common DSM-IV mental disorders are test driven using the DSM-MDA evolutionary classification system to demonstrate the benefits of the system for both reliability and concept validity.

Results        The MDA model places DSM disorders and the BPS model within an evolutionary framework.  The model maintains a BPS framework to make the evolution from an atheoretical to a theoretical classification system easier and avoids the Descartian dualism inherent in BPS model and DSM.  “Malfunction” correlates with “Bio”, “Dysfunction” with “Psycho” and “Sociability” with "Socio-cultural”.  It is proposed that each DSM disorder may have more than one possible aetiological basis. 

The Paradigmatic Failure of Psychiatry

Schools of Psychiatry

Failed models (over-arching)

DSM a failure?

BUT

Criticisms

Poor validity

Bottom line:

The BPS model a failure?

BUT

Criticisms of the BPS Model

Benefits of an evolutionary approach

Avoid Reductionism

Answers the second question…

Adaptation

What is a mental disorder from an evolutionary view?

Archetype Disorders

Archetypal propensities

Archetypes

Biosocial goals

1. Defense (fight or flight) 

2. Attachment

3. Dominance-striving

4. Reproduction

Archetypal systems

1. The stranger archetype

2. The affiliation and bonding archetype 

3. The hierarchical ranking dominance-submission archetype

4. The courtship & mating archetype

Stages in loss of attachment

Bottom line:

What might evolutionary approaches add?

Does Evolutionary Psychology have any answers?

Genesis & Now

The Massive Modularity Hypothesis

A Darwinian module

Mental architecture posited by evopsych

A proposed EvoPsych classification

1. Disorders Within the Person

   1. Internal to the module

      an individual's special-purpose computer is malfunctioning or its proprietary store of information is not what it should be (or both).

   2. External to the module

   3. the module producing problematic output is being given problematic input (garbage in = garbage out)

2. “Environment/Selection Mismatch”

   1. Genome lag hypothesis

3. Adaptive “deviant” behavioural strategies 

   (Murphy & Stich 1998)

…Evolutionary Psychiatry?

Evolutionary Neuroanatomy: Triune Brain

(MacLean 1973)

The reptilian brain

The limbic brain

Neomammalian brain

Evolutionary Stable Strategies

The Four “Time-Depths” classification of “Stress & Fear Circuitry” (Anxiety) Disorders

1. Mesozoic Era : Mammalian-wide fear circuits (140 MYA)

2. Cenozoic Era : Simian-wide fear circuits (20 MYA)

3. Paleolithic Era : H. Sapiens-wide fear circuits (200-14 TYA)

4. Neolithic era culture-bound genome-specific fear circuits (12 TYA)

My upgraded EvoPsych classification

1. Disorders of Mental Modules

   1. Disorders of Differentiation

   2. Disorders of ESS (Evolutionary Stable Strategies) 

2. Disorders of Integration (Module Connectivity)

3. Disorders of Balance Between Modules

(GG, 2005)

Archetype disorders

Our minds are poorly designed..!

Why are our minds so poorly designed?

A proposed general evolutionary classification

1. Novelty 

   1. From pathogens or competitors 

   2. From aspects of the modern environment 

2. Trade-offs 

3. Genes with costs as well as benefits 

4. All traits are a two-edge sword

5. Constraints 

6. Accidents and mishaps (too rare to shape defenses)

7. Defenses (often confused with diseases)

Nesse RM 1995

A proposed psychiatric evolutionary classification

1. Primary brain abnormalities 

2. Environmental trauma or uniqueness

3. Byproducts (adaptive but distressing)

(adapted from Nesse RM 1991) 

1. Primary brain abnormalities

2. Environmental trauma or uniqueness

3. Byproducts

Unveiling an upgraded BPS model…

The Malfunction-Dysregulation-Asocialisation ( MDA) Model 

1. Disorders of Malfunction

1.1 Modular - Mental disorders that result from localised (modular) brain malfunction due to abnormal differentiation, usually secondary to genetic vulnerability or injuries of the developing central nervous system 

1.2 Integrative - Mental disorders that result from NON-localised brain malfunction due to genetic vulnerability or injuries of the developing central nervous system, causing widespread cerebral dysconnectivity. 

1.1 Modular Malfunction

Autism as a breakdown of the Theory-of-Mind (ToM) Module

Causing “mindblindness” (Baron-Cohen 1997)

Machiavellian intelligence is a domain-specific faculty of inferring mental states of others (Brune 2001)

Pts with Autism, Aspergers & acute SCZ perform worse on ToM tasks 

(Brune 2005)

A Social Module?

Is ToM and consciousness part of a “social” module?

Group cooperation (reciprocal altruism) requires cheater detection algorithms (Trivers, 1971)

the ToM module is a self-awareness module crucial adaptation in humans 

“What consciousness does is to provide human beings with an extraordinarily effective tool for doing natural psychology. Each person can look in his own mind, observe and analyse his own past and present mental states, and on that basis make inspired guesses about the minds of others.”

(Humphrey 1987)

SCZ (acute episodes)

Pathological mind-reading inferences

Intentions of others perceived as negatively related to self

Pathological egocentrism

Antisocial Personality Disorder

Due to the absence or malfunctioning of the violence inhibition mechanism (VIM) module. (Blair 1995) 

Normally: VIM is activated by perception of distress in others, causing guilt and remorse, leading to an aversive withdrawal response

Model explains why psychopaths fail to develop moral emotions & fail to experience empathic responses to the suffering of others 

1.2 Integrative Malfunction

Dissociative disorders 

similarity between neurological disconnection syndromes and psychiatric dissociation syndromes (Edelman & Tononi 2000)

PTSD

an “Over-learnt Survival Response” with asynchrony caused by a failure of cortical inhibition to limit the trauma rehearsal (“overconsolidation”) generated by the limbic lobe

(Silove 1998)

(Bracha 2006)

Sequence of events in PTSD:

Fear response causes excessive activation of threat response neural circuitry

Inadequate orbital prefrontal feedback 

Failure to switch off activation of the threat response system 

Failure of recovery 

Schizophrenia 

a disorder of integration of the social brain (Burns 2004)

A disorder of over-pruning 

investigatory evidence for reduced cortical connectedness

neural network computer simulation

adaptive advantage of robust network pruning = the enhancement of cog functioning …until it pushes up against a “psychotogenic threshold”

(McGlashan & Hoffman 2000)

first rank symptoms (result from a disconnection b/w sense of individual self & outside world) smack of disconnection symptoms 

(Edelman & Tononi 2000)

2. Disorders of Dysregulation

2.1 Environmental trauma or mismatch– mental disorders may result from normal brain mechanisms becoming dysregulated as a result of exposure to novel environmental circumstances, idiosyncratic learning histories or sensory trauma causing maldevelopment of mind programs. 

2.2 Maladaptive memes -  behavioural dysfunction resulting from contagious propagation of maladaptive ideas. 

Types of brain trauma

2.1

2.2

2.1 Environmental Dysregulation

Epidemic of Depression

N=39,000 in 9 studies, in 5 global locations 

youth more likely to have had MDE than their elders, esp. in higher ec developed cultures
Mass communications

increased competition, unreachable goals, dissatisfaction with selves & family

decreased interactions,

New technology 

disintegration of families & communities 

(Nesse & Williams, Why We Get Sick, 1995)

Situations --> Depression

Loss of attachment – carer, mate (Bowlby)

Loss of rank – social status (Stevens & Price, 2000)

Loss of resources (Nesse 2000)

Internal 

Trauma

Bodily damage 

External

Bad decisions e.g. wasted effort pursuing risky goals 

Disruption to major life goals and enterprises

Depression as an Adaptation

Communicate need for help (Darwin, 1872)

Signal yielding in hierarchy conflict (Price, Sloman, Gardner, Gilbert, Rohde, BJP, 1994)

Disengage from unreachable goals (Nesse, AGP, 2000)

Regulate patterns of investment

Why doesn’t recovery occur?

Stevens & Price, 2000; MacLean, 1973)

Maladaptive Depression

Due to Conflict within the "Triune" Brain 

Results when all three "central processing assemblies" are not pulling together towards the same objective  

Stevens & Price suggest that maladaptive depression requires pharmacotherapy whereas adaptive depression requires psychotherapy

Involuntary yielding or "blocked higher level losing" 

Reasons for an “upper block”

1. Internal factors : predisposing personality traits 
obsessive & narcissistic traits 

high sensitivity to insult

2. External factors : 

loser cannot provide winner’s demands

winner continues attacks forcing victim into "learned helplessness" 

Anger-propagating Depression

Intractable anger causing maladaptive depression when something very unjust has been done to the person, which leads to resistance to yielding - often develops secondary to Chronic PTSD

1.  At the neocortical level, a conscious assessment of the threat is made & the decision whether to fight or yield is taken, taking into consideration learnt social values & rules.  

2. At the limbic level, a semi-conscious, emotionally-loaded assessment of the threat is made to  select a strategy. 

3. At the reptilian level, an unconscious, instinctive strategy is selected, beyond awareness of the social circumstances. 

2.2 Meme Dysregulation

Meme = evolution of culture (ideas)

Competitive co-evolution b/w genes & culture

Man must adapt to novel “cultural” environments/ influences (Dawkins, The Selfish Gene, 1976)

Mental disorder caused by:

Conflict b/w culture & gene 

Inability to adapt to culture

“Garbage input = garbage output”

The evolutionary explanation for brains

…our brains have evolved to make decisions that enhance reproductive success

Michael Gazzaniga, cognitive neuroscientist

So what determines human behaviour?

We are built as gene machines & cultured as meme machines
(Richard Dawkins, The Selfish Gene 1978)

The Invasion of human brains by culture, in the form of memes, has created human minds. (Daniel Dennett 1995)

Mimetic Lexicon 

http://pespmc1.vub.ac.be/MEMLEX.html

meme 

(pron. `meem') A contagious information pattern that replicates by parasitically infecting human minds and altering their behavior, causing them to propagate the pattern. (Term coined by Dawkins, by analogy with "gene".) Individual slogans, catch-phrases, melodies, icons, inventions, and fashions are typical memes. An idea or information pattern is not a meme until it causes someone to replicate it, to repeat it to someone else. All transmitted knowledge is memetic. (Wheelis, quoted in Hofstadter.) (See meme-complex).

meme-complex 

A set of mutually-assisting memes which have co-evolved a symbiotic relationship. Religious and political dogmas, social movements, artistic styles, traditions and customs, chain letters, paradigms, languages, etc. are meme-complexes. Also called an m-plex, or scheme (Hofstadter). Types of co-memes commonly found in a scheme are called the: bait; hook; threat; and vaccime. A successful scheme commonly has certain attributes: wide scope (a paradigm that explains much); opportunity for the carriers to participate and contribute; conviction of its self-evident truth (carries Authority); offers order and a sense of place, helping to stave off the dread of meaninglessness. (Wheelis, quoted by Hofstadter.) 

exo-toxic 

Dangerous to others. Highly exo-toxic memes promote the destruction of persons other than their hosts, particularly those who are carriers of rival memes. (Such as: Nazism, the Inquisition, Pol Pot.) (See meme-allergy.) (GMG) 

memeoid, or memoid 

A person "whose behavior is so strongly influenced by a [meme] that their own survival becomes inconsequential in their own minds." (Henson) (Such as: Kamikazes, Shiite terrorists, Jim Jones followers, any military personnel). hosts and membots are not necessarily memeoids. (See auto-toxic; exo-toxic.)

mimicry 

An infection strategy in which a meme attempts to imitate the semiotics of another successful meme. Such as: pseudo-science (Creationism, UFOlogy); pseudo-rebelliousness (Heavy Metal); subversion by forgery (Situationist detournement). (GMG) 

cult 

A sociotype of an auto-toxic meme-complex, composed of membots and/or memeoids. (GMG) Characteristics of cults include: self-isolation of the infected group (or at least new recruits); brainwashing by repetitive exposure (inducing dependent mental states); genetic functions discouraged (through celibacy, sterilization, devalued family) in favor of replication (proselytizing); and leader-worship ("personality cult"). (Henson.)

3. Disorders of Sociability ("Asocialisation")

Diagnosed if the behaviour of the individual leads to severe subjective distress, objective distress (of family/community) AND negative social or harmful consequences.
Characterised by behaviours that are not acceptable to the individual's community BUT are adaptive for their genes (transmission). 

The memes of the individual’s social group DIVERGE FROM the adaptive function of the individual's deviant behaviour.  

3.1 By-product

Patterns of emotion or behaviour that are painful or socially unacceptable, but nonetheless adaptive

3.2 Defense

An evolved solution to a challenge that may cause suffering & distress as part of the strategy to respond effectively to the threat

3.1 By-product

Delusional male sexual jealousy

a mate-guarding tactic 

Although an uncomfortable, undesirable state that can give rise to antisocial acts, it is likely to increase reproductive success & be maintained by NS.

(Daly, Wilson and Weghorst 1982; Symons 1979) 

3.2 Defense

Anxiety disorders

Panic disorder

Startle may activate the Fight or Flight Program

… to motivate to urgent action

for survival

(Walter Cannon, 1929)

Situations evoking anxiety as a defense

Harm from strange humans : Stranger anxiety 

Separation from carer : Separation anxiety 

Threats to status/group membership : Social anxiety 

Socially unaccepted impulses : Obsessive self-doubt

Lack of food or other resources : Obsessive hoarding 

Getting sick : Hypochondriasis/Obsessive cleanliness

Dangerous small animals : Small animal phobias 

Potential attack to family members : General anxiety 

Imminent attack by predator : Panic

Environment in which attack is likely : Agoraphobia 

(Adapted from Nesse, 1990)

A two-edge sword

Lungs: blood O2

Heart: O2 blood delivery

Muscles: O2 metabolism

GIT: bld flow to gut

Brain: activation of fear circuitry

Lungs: SOB, choking, parasthesia 

Heart: Palps, chest pain, flushes

Muscles: Trembling, tension, sweating 

GIT: Dry mouth, butterflies, nausea, belching

Brain: Dizziness, faintness, lightheadedness, catastrophic cognitions & fear

The Smoke-Detector Principle

Anxiety is a useful defense

…but it uses extra calories, makes us less fit for everyday activities & damages tissues

So why is it so readily triggered?

Because the cost of getting killed even once is enormously higher than the cost of responding to 100 false alarms

Nesse

Test-driving MDD & Psychosis

EVOLUTIONARY CLASSIFICATION DISORDER: Major Depressive Disorder 

1. Malfunction 

Due to general medical disorder 

Drug-induced

Melancholic & psychotic depression

Pseudodementia (subcortical)

Dysthymia due to deficit in reciprocal exchange module (McGuire, Murphy) 

2. Dys-regulation 

Maladaptive depressions (conflict within the Triune brain) e.g. Anger-Induced Depression 

3. Sociability 

Dysthymic temperament for social cohesion (Akiskal) 

Adaptive depressions e.g. due to Involuntary Yielding in Social Competition, to disengage from unreachable goals, to regulate patterns of investment 

EVOLUTIONARY CLASSIFICATION DISORDER: Psychosis

1. Malfunction 

Due to general medical disorder

Drug-induced

Schizophrenia as Disorder of Integration due to Over-Pruning, As a Disorder of the Threat

Response Archetype

2. Dysregulation 

Shared psychotic

3. Sociability 

Delusional jealousy 

Disorder of Spacing in SCZ

More information:

www.ep.org.au