Thursday, November 23, 2006

Schizophrenia and Autism: The Two Cultures.

Mind Hacks has highlighted two posts from the BPS Research Digest that highlight the work of Daniel Nettle, related to Scizotypy and evolutionary benefit especially the linkages between schizotypy and artistic creativity.

To recap the schizotypy dimensions:

  1. Unusual experiences: The disposition to have unusual perceptual and other cognitive experiences, such as hallucinations, magical or superstitious belief and interpretation of events . In the clinical form manifests as positive symptoms of hallucinations and delusions.
  2. Cognitive disorganization: A tendency for thoughts to become derailed, disorganized or tangential. In the clinical form manifests as the positive symptoms of disorganized speech and flight of ideas.
  3. Introverted anhedonia: A tendency to introverted, emotionally flat and asocial behavior, associated with a deficiency in the ability to feel pleasure from social and physical stimulation. This manifests clinically as the negative symptoms of flattened affect,alogia and avolition.
  4. Impulsive nonconformity: The disposition to unstable mood and behavior particularly with regard to rules and social conventions. Manifests clinically as disorganized and socially inappropriate behavior like dressing inappropriately.


To summarize the key findings of the first Nettle paper:

  1. Unusual Experiences dimension (in general population) correlated positively with number of partners and mating success. This relationship was mediated by creative activity. Thus, unusual experiences are hypothesized to lead to creative activities, which in turn increase reproductive fitness.
  2. Impulsive Nonconformity had a direct positive correlation with number of partners and mating success. It independently led to increase in reproductive fitness and the effect was not mediated via creative activity.
  3. Introvertive Anhedonia decreases creative activity, and also has a direct negative effect on mating success.
  4. Cognitive Disorganization seemed to had no significant effect on mating success.
  5. Thus, while part of the reason for continuing prevalence of schizophrenia/schizotypy may be explained by the direct effect of Impulsive Non-conformity on Mating Success, the other part can only be explained by the benefits of creative activity that are conferred by Unusual Experiences.

As Introverted Anhedonia has a negative effect on both creative activity and mating success, it seems reasonable to posit, that while schizophrenia patients may suffer from the negative interaction between Unusual Experiences and Introverted Anhedonia; some of their relatives may benefit from the unusual experiences, while being spared from the effects of Introverted Anhedonia, and thus be specially selected for mating success that is mediated by creative activity. This creative advantage that the relatives of schizophrenia have, may have led to the fixation of this disorder in humans.

The second nettle paper explores the relationship between schizotypy and artistic creativity. the key finding here are:

1. Poetic creativity:
  • Unusual Experiences score increase in a significant manner from non-poets, to hobbyists to serious poets. It slightly decreases with professional poets.
  • The same trend is shown by Impulsive Nonconformity and Cognitive Disorganization.
  • Introverted Anhedonia, on the other hand, shows a non-significant trend to decrease with increasing creative activity.
2. Visual art creativity:
  • The trends for Unusual Experiences, Impulsive Nonconformity and Cognitive Disorganization are the same as in case of poetry, the only difference being that Cognitive Disorganization trend is not significant.
  • Introverted Anhedonia, on the other hand, shows a significant trend to decrease with increasing creative activity.
3. Mathematical creativity:
  • The trends are opposite to that of poetic and visual arts creativity in this case.
  • The scores for Unusual Experiences, Impulsive Nonconformity and Cognitive Disorganization decrease with mathematics engagements level.
  • The scores for Introverted Anhedonia, increase and correlate with mathematical activity.
4. The conclusion is that schizotypal traits like Unusual Experiences, Impulsive Nonconformity and Cognitive Disorganization are instrumental in creative thinking and thus have beneficial effects of stimulating creativity. Though the effect size of Unusual Experiences is the strongest, other traits also have significant effects. Increasingly serious creative engagement is associated with a decrease in introvertive anhedonia and this negative trait is thus a liability.

The authors thus conclude:

The findings provide some support for the two-factor model of Barron (1972). Creative groups are as high as patients on unusual experiences and cognitive disorganization, but lower than controls on introvertive anhedonia. Thus, artistic groups and psychiatric patients share divergent thought, but they differ in that the latter are troubled with negative symptoms such as avolition and anhedonia, whilst the former are unusually free of these traits. This is also congruent with Schuldberg's findings that creativity scores are positively correlated with scales of positive psychotic or hypomanic symptoms, and negatively.


This, the author had hypothesized earlier in the paper, might be an alternative to an inverted-U model of benefits provided by Schizotypal traits.:

An alternative possibility comes from the two-factor approach of Frank Barron. Barron (1972) argued that successful creativity combines deviant and psychopathological traits with high scores on measures of 'Ego strength'. Ego strength includes resilience, ability to cope with stress, self-control and high levels of experienced well-being. Ego strength is thus a mediating factor that determines whether schizotypy is translated into damaging symptoms or healthy creative output. Schuldberg's(1990) work is relevant to this model, finding as it does that scales based on positive symptoms correlate positively with creativity scores, whereas scales based on negative symptoms correlate negatively. Thus, a lack of negative symptoms would appear to be equivalent to high 'Ego strength' in Barron's terms. The prediction in terms of the O-LIFE dimensions would therefore be that creativity would be associated positively with unusual experiences but negatively with introvertive anhedonia.


He further tries to correlate this with the 'systemising' theory of autism:

This profile supports the picture of the mathematical mind as having opposite features to the artistic one, with a narrow range of associations (low unusual experiences), an interest in order (low cognitive disorganization), and in routine (low impulsive nonconformity). These findings are consonant with Baron-Cohen's work on systemising as a core feature of autistic spectrum disorders. Systemising is a cognitive style characterized by a drive for order and regularity, which is elevated in high-functioning autism and in mathematics and engineering (Baron-Cohen et al., 2003; Baron-Cohen et al., 2001). The constellation of autism, systemising and science appears to be in many respects the opposite tail of the distribution to the constellation of arts, unusual experiences and affective and psychotic disorders explored in the present study.


The authors, also present the following theory of autism:

Autistic traits are in many ways the converse of the unusual experiences component of schizotypy. Whereas schizotypal thought is characterized by often metaphorical leaps from domain to domain, remote associations, and broad attentional set, autism is characterized by narrow interests and liberality, with occasionally highly developed abilities in tasks requiring systematic and convergent thinking.


I believe they have stumbled on a very important conceptualization. I myself had been contemplating the Schizophrenia- Autism linkages for quite some time. In my view, the contention that Schizophrenia reflects aspects of artistic creativity, while Autism may reflect aspects of mathematical creativity is a positive diversion form the usual male/female systematizing/empathizing spin on Autism. It is instructive to note, that while Autism is a predominantly male illness, prevalence of Schizophrenia too, is greater in Males compared to females. thus, a simple Male- Female dichotomy does not work.

I do believe that there are theory-of-mind deficits in Autism and these are responsible for their social difficulties, and this may be the opposite of the empathetic brain, but that deficit in empathy should not be construed as equivalent to a positive endowment with systematic thinking. In my view, the empathy defect is independent of the other defects like communicative and repetitive and stereotyped behavior defects. The empathy defect has to do with emotions and feelings, while the other defects might be cognitive and behavioral in nature.

Both Schizophrenia and Autism are spectrum disorders, and hence we will consider differences between the spectrum.

Let me now address the differences in Autism and Schizophrenia spectrum :

  1. Literal vs Metaphorical thinking. One of this blog's reader, Mrs Mc Ewen, had recently left a comment on this site and I discovered that she is a mother of two autistic kids and maintains a blog related to that. I found one of the entries related to Literal interpretation in autism both humorous, informative and sad at the same time. On the other hand, I am well acquainted with the metaphorical thinking indulged in by schizophrenics (I've written a sort of Novella that revolves round that theme), and as I find the Conceptual Metaphor Theory for linguistic semantics full of promise, I have no trouble understanding the language developmental delay in Autism, or the literary/ artistic creativity of Schizotypal pro band. After all, much of art is using symbolism, metaphor etc and involves non-literal interpretation. This difference alone can account for the communication deficits faced by Autistic children. This is related to the schizotypy dimension Unusual Experiences.
  2. Convergent Vs Divergent thinking: Schizophrenia spectrum is marked by cognitive disorganization, flights of ideas and looses associations. It is also marked by including too much of context and in pathological cases characterized by an effort to relate each and every happening to some preexisting context (if the context is of Paronia- every event is a conspiracy; if the context is of grandeur, every event is significant and referring to self). Autistic spectrum, is not only marked by the absence of these and a low score on the corresponding schizotypal trait; but by an opposite tendency of Central Coherence. there is some research that indicates, that Autistic children show both perceptual and conceptual central coherence: i.e. a tendency to only focus on one piece at a time and an inability to use gestalt perception or conceptualization whereby one could indulge in a top-down 'imaginary' assembly of fragments to identify an object. thus, they take , too little of context, in my view and make lesses association than desired. One can also hypothesize, that would yield lesser scores than controls and definitely lesser scores than schizophrenics on the unusual/ novel object uses task. This may also partially explain symptoms like circumscribed and specialized interests in autism. This is related to Schizotypy dimension Disorganized Thinking.
  3. Reality vs. Fantasy (imagination) orientation: This relates to whether one has an ability to indulge in make-believe or in activities like pretend play. I believe that this propensity to use imagination may be linked to the unusual experiences like hallucinations that are found in schizophrenics. Magical thinking, involving endowing inanimate objects like Voodoo dolls or lucky charms, with causative powers may be converse of the autistic inability to differentiate between animals and inanimate objects, or to easily learn to distinguish between self-intended motion of a human/ animal and a pushed or caused motion of an inanimate object. It is instructive to pause here, and reflect, that much of human Agreeableness and Empathy also has to do on make-believe. One may not always love one's friend, but out of respect and social courtesy, one would always pretend to do so. The reality orientation of autistic children, (apart form any empathy/ mirror neuron defects) may also underlie their social difficulties like inability to make friends and impaired social play. This is related to the schizotypy dimension Unusual experience.
  4. Routine and order Vs. Novelty preference: Autistic children are characterized by repetitive and stereotyped behavior. Schizophrenia spectrum on the other hand is high on Openness to Experience and usually display preferences for reckless, novel, socially inappropriate and sensation seeking behavior. This difference may underlie the stereotyped behavior like rigidity exhibited by autistic children. This is related to schizotypy dimension Impulsive, Nonconformity.

Overall, one possible mechanism underlying these differences can be a sensori-motor and conceptual gating defect in both the disorders- with schizophrenia signifying a very broad sensori-motor and conceptual gate with consequent broad attentional span, loose associations and too much of context; and Autism representing a very narrow spatial and temporal gate with consequent specialized interests and focus, few associations, literal and convergent thinking.

If one couples this with the phenomenon of pre-pulse inhibition (defect of schizophrenia) , then it may be theorized that as a schizophrenic would interpret all stimuli in a novel way (presentations of a stimuli earlier, does not lead to its memory or the suppression of the startle response), hence it would also develop preference for, or at least not be intimidated by, a novel item. On the other hand, due to the smaller sensory gate, and normal PPI, the autistic children would mostly be exposed to the smae stimuli over and over gaian and may develop a preference for it over any new stimuli which, when gated through its small gate, would cause it to get startled. I am even tempted to theorize that autistic children may have a high PPI than normals, but a quick Google search didn't corroborate my speculations.

Lastly, a discussion of Anhedonia, and how that interacts with positive schizotypy and autism will need some more thinking and conceptualization. For now, I am tempted to posit that Anhedonia may be one of the dimensions of the female counterpart of Schizotypy-Autism thinking styles. Females, I believe, are more prone to depression (the primary correlate of Anhedonia) and maybe just like a Schizotypy-Autism spectrum that is along cognitive thinking styles; there might exist a Depersonlization-Bipolarity spectrum that runs along the emotion-motivation feeling styles and may reflect the two fundamental styles of emotional processing- one involving use of too much emotion and motivation (bipolarity) and the other characterized by lack of emotion and motivation (depersonalization).

While creativity (thinking) of both types (scizotypal-autistic or artistic-scientific), might have been selected by sexual selection in males; the corresponding traits that would be under sexual selection for females might be virtue/aesthetics (feeling) of both types: one subjective and based on personal constructs of emotions and motivations and the other objective and based on utilitarian concerns and needing one to put aside one's own feelings and emotions.

Just a speculation. Do let me know, your views and opinions (or any supporting researches)!


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13 comments:

mcewen said...

You're overloading my 'research' topics quotient! And it's supposed to be a holiday today!
Happy Thanksgiving

PH said...

I really enjoyed reading ur blog; your breadth and enthusiasm of topics is commendable. Thanks and continue writing!

Sandy G said...

mcewen, I hope you were able to enjoy the thanksgiving holidays despite my evil attempts to keep you hooked to your computer. Thanks for sharing the autistic world of your kids with us.
ph, Thanks for dropping by and commenting.

David Harmon said...

Hmmm... and where does that leave me, as someone with Non-verbal Learning Disorder (that is, autistic spectrum) who's also experimented successfully with Neo-Paganism and shamanism, plus has some of my family's artistic talent?

Sandy G said...

Hi David,

Autism is a spectrum disorder, and I believe it has at least two major components: one identified by weak central coherence and elaborated in my mail and referring to the underlying convergent cognitive thinking style; the other a dysfunctional theory of mind module causing social difficulties. You might have a reasonably good central coherence, but may have a deficit in ToM and thus be still autistic despite experimenting with shamanism etc.

Also, remember that some autistic savants display remarkable artistic capabilities, but mostly related to realistic and detailed depictions and not so much characterized by imagination or symbolism.

Prerona said...

Sandy, I intuitively agree with you. Infact I thought the same and was surprised to see you agree and was hoping to get some links to papers/research on the same :) You too let us know if you find any research on this or anyone working in related areas? :)

Sandy G said...

Hi Prerona,
Actually I was surprised to see my theory of Schizophrenia- Autism linkages appear in the Nettle Paper (and sort of pissed too, that some of my important insights had been shared with the world by someone other than me:-), but then I believe that I have been able to add to the original Nettle theory my own concepts/ mechanisms, especially the cultural dimensions and the central coherence and sensory gating approaches.

I believe mildly in synchronicity, in the sense that great minds think alike, so I am not surprised that you too had thought along these lines. Now the scientific method demands that we work together to support our thesis and build on it.

I have posted a new post, relating the Schizophrenia-Autism differences to differences in Cultures with respect to cognition as well as religiosity. Do let me know if you are able to extend this to some other planes/domains and are able to get some supporting evidences.

Prerona said...

Sandy, I am going through your new post. Was home (India) for hols so no regular net access. Look forward to getting back in mode from this week! I was wondering if I could discuss something related to this (your interest in schizophrenia) with you. If you dont mind, can I ask for your email or messenger id? Thanks, Prerona

Sandy G said...

Hi Prerona,

My email id is sandygautam17ATgmailDOTcom (remove capitals) and my IM id on Yahoo messenger is sandygautam.

Looking fwd to the discussions.

Julia said...

What do you make of McDD?

http://en.wikipedia.org/wiki/McDD

For example, I am a diagnosed childhoo-onset paranoid schizophrenic, but I am also diagnosed with Aspergers, and both of the labels are valid. My brain does ALL of the things you have described, for noth conditions. How does your theory account for this?

Sandy G said...

Hi Julia,

One way to look at this would be to treat this as similar to mixed episodes in bipolar disorder. Here both symptoms of Mania and depression are present in the same individual though traditionally Mania and depression are thought of as opposite poles on a continuum. In effect though Autism and Schizophrenia/psychosis are opposite extremes, in some individuals both may be present. However, also note the differences form mixed episodes in bipolar; there the mixed state as well as mania and depression happen in the same individual over time; here the disorders itself are simultaneously present in the individual.

Another example I can think of is of recessive alleles for both disorder at the same gene locus. (lets for example consider that eye color is due to recessive alleles at the eye-color locus). Now suppose that recessive allele S confers risk of schizophrenia and N is the normal variant. so SS is schizophrenic; SN is on the continuum toward schizophrenia and normality, perhaps a schizotypal individual. Suppose also that recessive allele A at the same locus makes one susceptible to Autism (they are opposite poles so evidently should work on same locus / loci). Thus AA is autistic and AN is asperper's; now consider the rare scenario where one gets AS genotype ; in this case one might be asperger's and schizotypal; in rare scenario this may develop into full-blown child-onset schizophrenia and classified as PDD_NOS or McDD.

To test my theory one can see the frequencies of Autistic and Schizophrenics and also the McDD iondividuals. If there was no interaction, Autism and schizophrenia should be independently inherited and P(mcDD) = P(Autism) * p(schizophrenia) where P is probability of an individual in a population belonging to that disorder. As my theory predicts there should be some interaction (the gene locus is same), so P(mcDD) should be different from that calculated from above (though I lack the requisite math knowledge to come up with a good formula!)

Hope this clarifies!!

Julia said...

Thank you!

Anonymous said...

I believe children with relatively mild ASD, who often go undiagnosed and fall through the cracks, wind up with diagnosable mental disorders in adulthood. My son has ASD/NVLD and is very cognitively disorganized, especially with tasks that are challenging, which are many; and yet he was adding and subtracting triple digits in his head at age 5 and knows more about geography and related world languages than most adults on this forum. My mother has schizoaffective disorder and was similarly brilliant and socially misfit and obstinate and aloof as a child, though probably she was not as disorganized as my son. A theory that polarizes these 2 areas (psychotic disorders and ASD) I think is missing something significant. My belief is that if ASD is intervened upon early and persistently, the risk of adult mental illness, not to mention drug abuse, alcohol abuse, and crime will be reduced. Just my opinion from the middle of a generational sandwich of disorder.