EP lec

Home Up

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. 

Conclusions       The MDA evolutionary classification system permits maintenance of DSM-IV diagnostic reliability whilst gaining the benefit of concept validity.

 

 

The Paradigmatic Failure of Psychiatry

 

Schools of Psychiatry

 

"With the split of psychiatry into schools, each teaches its own facts, methods, and ideas, convinced it is the psychiatry. Students shop among the schools, and the public ask psychiatrists what kind they are. Every year new varieties come and go like fashion styles."

Leston Havens 1973, 2005 

 

Failed models (over-arching)

 

Objective-descriptive (Kraeplin, Janet, Bleuler, Maudsley, Beck)

Psychoanalytic (Charcot, Breuer, Freud)

Existential (Jaspers, Minkowski, Binswanger)

Interpersonal/Social (Meyer, Sullivan)

Eclecticism - descriptive non-aetiological classifications 

DSM

The Biopsychosocial model (Engel 1980)

 

DSM a failure?

 

Essential in allowing researchers to study comparable groups 

Achieves its aims of:

Accurate descriptions (language free of theoretical biases)

Reliability among multiple users (high cross-clinician agreement)

Empirical (Akiskal 1989)

 

BUT

 

Criticisms

 

Not guided by any theory about the structure and functioning of normal minds

Encouraging simplistic thinking of psychiatric syndromes as discrete diseases (Kendell 1984)

Neglecting maladaptive psychological processes

Splitting psychiatry from general medical disorders gives the false impression that the mechanisms are different for both (Waterman)

Imprecise

 

Poor validity

 

Imagine trying to construct a classification system for malfunctions occurring in a computer network that must be based entirely on clusters of user-salient symptoms (without any theory about its component parts & their functions). 

It would classify together problems caused by totally different underlying mechanisms or processes & which may require totally different remedies.

It would fail to classify together problems with the same underlying cause (& requiring the same remedy) if they manifest themselves in different ways under slightly different conditions. 

The result would be set of categories that are massively heterogeneous from the point of view of someone who understands how the system works. 

(Murphy & Stich 1998)

 

Bottom line:

 

Developing a descriptive vocabulary that achieves a high degree of cross-clinician agreement may be served by summative reasoning, but its service to condition validity is another matter

(McGuire & Troisi 1998)

 

The BPS model a failure?

 

Essential in vaccinating against dogmatism (biological reductionism or psychoanalytical orthodoxy)

Provides room for an eclectic approach utilising psychotherapy and social work in a neuroscience dominated environment

 

BUT

 

Criticisms of the BPS Model

 

“It is like going to a restaurant & receiving a list of the ingredients rather than a menu”

(Paul McHugh 1998)

“Too eclectic to provide useful organising concepts around which to understand psychiatry” 

(Ghaemi 2005)

“To the extent that it is true, it is a trivial truth” 

(Ghaemi 2005)

“Psychiatry is a conceptual mess due to linguistic conceptual conventions”

Fundamentally dualist model: Descartes without the pineal connection

Fitting 21st C science into a 17th C framework doesn’t work

Contributes to:

Separation of psychiatry from the rest of medicine

Stigmatisation of patients

Inequitable distribution of resources

Distortion of DDx and treatment practices 

Confusion of aetiology & pathogenesis

Impairment in ability to communicate to students & general public modern psychiatric concepts

(Waterman)

 

 

Benefits of an evolutionary approach

 

Avoid Reductionism

 

"Form follows function" is an architectural philosophy attributed to the great American architect Louis Sullivan (1), and later taken up by the Bauhaus movement. It stresses that the form of a building should reflect its function. Neuroscientists have used the converse of this dictum to learn the functions of neural circuits, believing that if we study neural architecture, it will lead us to an understanding of how neural systems function. 

W. B. Kristan and P. Katz (Current Biology 2006 16:R828)

Consider the elegantly simple central nervous system of C. elegans; with only 302 neurons in its entire nervous system, it is considerably less complicated than a slice of cortex. Every connection in the C. elegans nervous system has been obtained from serial electron microscopy 20–30 years ago. Yet, despite this exquisitely detailed knowledge, not a single behavior has been successfully inferred from looking at the connectivity pattern alone.

Graham Brown 1911, Marder, E., and Calabrese, R.L. (1996)

 

The two biologies that are concerned with the two kinds of causations are remarkably self-contained. Proximate causes relate to the function of an organism and its parts as well as its development, from functional morphology down to biochemistry. Evolutionary, historical, or ultimate causes, on the other hand, attempt to explain why an organism is the way it is. Organisms, in contrast to inanimate objects, have two different sets of causes because organisms have a genetic program. . . . (pp. 67, 68)

(Mayr, Growth of Biological Thought, 1982)

(Tinbergen 1963)

 

Answers the second question…

 

Reductionistic approaches miss half the story because most research tries to explain “what” & “how”

Evolutionary approaches examine “why” we are susceptible to maladaptive mental & behavioural phenomena by considering design characteristics 

Proximate & Evolutionary explanations are not competitors, but two halves of a whole

 

Adaptation

 

Any anatomical structure, physiological process or behaviour that makes an organism more fit to survive & reproduce in comparison to other members of the same species is an adaptive trait 

(Sober 1987, West-Eberhard 1992)

 

What is a mental disorder from an evolutionary view?

 

Abnormal phenomena causing biological disadvantage 

(Scadding 1967)

Disorders are the result of things that have gone wrong with evolved structures that allow for adequate functioning (which, unabated, leads to reproductive disadvantage) 

(Klein 1978) 

Also: social undesirability 

(Wakefield 1992) 

 

Archetype Disorders

 

Mental disorders the result of “frustration of archetypal intent” 

(Stevens 1982)

 

Archetypal propensities

 

The function of a behaviour is its purpose … the beneficial consequence through which NS acts to maintain a trait 

(Hinde 1982)

Natural selection has equipped us with lifespan-specific, context-sensitive archetypal propensities to navigate biosocial imperatives that facilitate inclusive fitness.

(Stevens & Price 2000)

 

Archetypes

 

Human “instinct” (William James 1890)

“Collective unconscious” (CG Jung)

Mother-infant instinct (Bowlby 1958)

 

Biosocial goals

 

1. Defense (fight or flight) 

2. Attachment

3. Dominance-striving

4. Reproduction

(Gardiner 1988) 

 

Archetypal systems

 

  1. The stranger archetype

  2. The affiliation and bonding archetype 

  3. The hierarchical ranking dominance-submission archetype

  4. The courtship & mating archetype

(Stevens & Price 2000)

 

Stages in loss of attachment

 

Protest: anxiety

Despair: Grief/Depression 

Detachment: Defensiveness/self-reliance/poor sociability/personality dysfunction 

(Adapted from Bowlby, Attachment & Loss, 1969)

 

Bottom line:

 

Whatever else they are, most mental conditions are conditions of failed functions

 

What might evolutionary approaches add?

 

A theory of behaviour, motivations & function 

A theory of gene-environment-behaviour interactions

Causal hypotheses 

A non-judgmental, normalising, humanising explanatory model for patients

Integration of prevailing models into a framework

An evolutionary classification…?  

(McGuire & Troisi 1998)

(Nesse)

 

 

 

Does Evolutionary Psychology have any answers?

 

Genesis & Now

 

"In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation." 

(Darwin: Origin of Species)

 

The Massive Modularity Hypothesis

 

“Human nature” refers to the accumulated specialized neural circuits that are common to every member of a species 

Our modern skulls house a stone age mind 

Our cognitive architecture resembles a confederation of hundreds or thousands of functionally dedicated computers (modules) designed to solve adaptive problems endemic to our hunter-gatherer ancestors…

…There are specialized systems for grammar induction, for face recognition, for dead reckoning, for construing objects and for recognizing emotions from the face. There are mechanisms to detect animacy, eye direction, and cheating. There is a "theory of mind" module .... a variety of social inference modules .... and a multitude of other elegant machines.

(Cosmides & Tooby 1995)

 

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

 

Ritualised agonistic behaviour

Resource Holding Potential

Social attention holding potential

Hawk dove strategies

 

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

 

Should be mode-of-acquisition and brain-evolution based

Based on evolved fear circuitry traits that have outlived their usefulness

(Bracha, in print, 2006)

 

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

Separation anxiety 

Extreme fear of adult non-kin males in toddlers

Extreme fear of high elevations in adults

 

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

Fear of:

snakes, reptiles, 

confined spaces, darkness, water immersion, 

suffocation during forest fire (CO2-induced PA), 

muscle exhaustion under predation (Lactate-induced PA)

Acute jaw-clenching (fear-induced) 

Chronic incisor-grinding (stress-induced) 

 

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

Compulsive:

Lock & stove checking

Washing (Obsessive fear of contamination)

Hoarding (esp. tools, weapons & leather goods)

Extreme fear of insects or mice

Fear of scrutiny by non-kin conspecifics (Generalized Social Phobia)

 

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

Primary dissociative disorder

Psychogenic:

Non-epileptic attacks (pseudoseizures)

Pseudoparalysis (e.g. limping)

Imbalance (Pseudocerebellar symptoms)

Blindness

Epidemic sociogenic illness (“epidemic hysteria”)

 

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

 

Mental disorders may manifest as a failure to meet biosocial imperatives (goals or social roles) by the 4 archetypal propensities

Stevens & Price 2000

 

Our minds are poorly designed..!

 

Bottom line:

Vast prevalence

Huge comorbidity

Onset at age of peak health

Waxing & waning courses

Huge fitness costs

 

Why are our minds so poorly designed?

 

Because of past evolutionary compromises & trade offs organisms are not optimally designed the target of selection is the whole organism not individual traits

Historical 

McGuire & Troisi 1998

Mayr 1983

 

Selection does not optimise adaptive traits or strategies as much as it gradually eliminates unfit traits/strategies

Tuomi et al 1983

 

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

Caused by genetic abnormalities, infection, toxins, trauma

Result in:

Malfunction e.g. SCZ, autism, learning disorders, dementia

Dysregulation of adaptive responses e.g. melancholia, BPAD

 

2. Environmental trauma or uniqueness

Normal brain mechanisms

Exposure to novel environmental circumstances, idiosyncratic learning histories or trauma

Examples: 

some anxiety & depressive disorders

Addictions

fetishes

 

3. Byproducts

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

Examples: 

Sexual infidelity

Shyness

Homicide due to male status striving; 

Abuse & infanticide by stepparents 

(Daly & Wilson 1988)

 

 

 

Unveiling an upgraded BPS model…

 

The Malfunction-Dysregulation-Asocialisation ( MDA) Model 

 

Places DSM disorders & the BPS eclectic (atheoretical) model within an evolutionary (aetiological) framework

General evolutionary explanations (y-axis) and the organism-specific archetypal (functional) disruption (x-axis) grouped together because they are complementary

Proposal that each DSM disorder may have more than one possible aetiological basis

(Galambos, 2006)

 

Maintaining a BPS framework makes the evolution from an atheoretical to a theoretical classification system easier, whilst providing a solution for the Descartian dualism inherent in BPS model and DSM:

Malfunction correlates with “Bio”

Dysfunction correlates with “Psycho” 

Sociability correlates with "Socio-cultural”

 

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

 

Mental disorders that result from dysregulation of established defenses leading to failure to achieve specific biosocial goals of the entire organism. 

 

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

Blunt

Toxins

Somatosensory

2.2

Ideational

 

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 </