|Year : | Volume
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Does application of complexity theory simplify concepts of psychiatry: Analogies and insights
Jyoti Prakash1, K Chatterjee1, S Shankar2
1 Department of Psychiatry, Armed Forces Medical College, Pune, Maharashtra, India
2 Consultant Rheumatologist and Clinical Immunologist, O/o DGAFMS, New Delhi, India
|Date of Submission||23-Feb-2021|
|Date of Acceptance||25-Mar-2021|
|Date of Web Publication||10-Jun-2021|
Department of Psychiatry, Armed Forces Medical College, Pune - 441 040, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Scientific curiosity has not been able to explain the cause of psychiatric illness based on primarily biological or social paradigm. Available literatures were explored to understand causality of psychiatric illness from perspective of physics. Theory of complexity and other relevant theories were extrapolated to address these questions. Mental illness appeared to be a complex interplay of reductionism and emergentism, genetic and epigenetics, stress and the vulnerability or the core and the periphery. Mental illness displayed complex interaction between biological trait and environmental state.
Keywords: Complexity theory, emergence, epigenetics, psychiatry
| Curiosity Experiments and Necessity Invents!|| |
The insatiable appetite of science to understand the causal factor of illnesses has led to significant advancement in modern medicine. The various laboratory experiments and clinical research have mapped out the most micro- and macroenvironment of human body. Hypothesis so generated was validated upon with basic and applied research to come up with most certain explanation which logically explains the phenomenon. This understanding of human body and physical illness has significantly helped the therapist to manage the malady with more precision and in a personalized manner. Individual variability has been understood; complex mechanism has been reduced to simple steps and approach tailored to individual and the disease has brought gratifying reduction in related morbidity and mortality statistics over the years.
However, the science is still riddled with complexity of psychiatry, where the tenets used for understanding of other illnesses have not born similar fruits. The cause-and-effect analysis, action, and the reaction and simplification of the processes have led to inconsistent and varying results. This comes out as one of the strongest reasons for lack of precision in practice of psychiatry and advent of varied treatment models based on individualized understanding of psychosocial model of the psychiatric illness by the therapists.
Existing literature has attempted to understand psychiatry from one extreme of reductionism (based primarily on genes and molecules) to another of emergentist (cannot be predicted by its biological elements. Social or naturalistic) and the wide spectrum of possibilities in between. The results have been varying and most working treatment modality serendipitous.
We author here would like to understand the causality process of psychiatry from the perspectives of physics. The complexity theory has given rationale and understanding to many earlier unexplained phenomena and may here yield better insight to science of psychiatry and impetus of precise research.
| Causal Loops|| |
Causality in the psychiatry has been viewed by some researchers as causal loops consisting of biological, genetic, psychosocial, cultural, and economic elements. While biological and genetic components are known to have discrete function, which are context independent, function of other components in the loop may not be predicted by its mere properties of its elements. The whole may be more than sum of all and purely context dependent. Action of these components may further modify its property or that of the proximal elements, as in neuroplasticity, or may culturally transmit to the next generation as the entire system feedbacks its constituents. These loops may be recursive leading to oscillation between the levels iteratively. A causal loop in alcohol dependence syndrome is exemplified in [Flow Diagram 1].,,,,,,,,,
The stress diathesis model in psychiatry proposed by Meehl, Bleuler, and Rosenthal resonates with the above concept. The diathesis meaning predisposition in Greek began from biological vulnerability but now is an umbrella term for biological, psychological, social, and cognitive predisposition which makes a person more prone to a disorder. A diathetic person responds abnormally to erstwhile conditions of life perceived to be normal by majority of others. This vulnerability however, by itself, is not enough to cause a disorder. It would need some releasing or amplifying factors to be pathogenic which most often is stress. The manifestation of illness differs variably with degree of risk factor, degree and number of experienced stress, point in time, etc. The interaction between stress and diathesis is dynamic and continuous in nature; thus, the requirement of stress for diathesis to manifest illness may increase and decrease over time. This dynamic theory supports the kindling phenomenon and its role in mental illness. Many psychiatric illnesses such as schizophrenia and depression have been explained based on this model.
| Reductionism Versus Emergentism|| |
While the hard reductionism explains the phenomenon solely on basis of molecular science, hard emergentism negates its deducibility from any of the biological processes and thrusts reliance on naturalistic and social phenomenon. The available evidence in psychiatry shows causality of many a psychiatric disorder in a spectrum ranging from soft reductionism to soft emergentism, where neither purely molecule or social theory holds an etiological ground.,, While the fragile X, a known genetic disease presenting with autistic features, is at reductionism end; cultural bound syndrome, a constellation of signs and symptoms with variable psycho-social underpinnings stand at emergentism end. Psychiatric illnesses due to inborn error of metabolism, dementia, organic psychiatric illnesses, delirium, substance use disorder, psychotic disorder, neurotic disorder, etc., are examples on a spectrum where evidence for genetic/biological basis recedes and the social/psychological explanation becomes stronger. Our existing classification systems in psychiatry like DSM-V and ICD-10 are also primarily a typology of syndromes and disorders with less reliance on an etiological basis. Although this gives a general guideline for management of psychiatric patients, this fails to give the etiological construct which is vital to address the illness specifically. The scientist has embarked upon designing a classificatory system based on the available evidence gathered in psychiatry for further research and possible intervention on those lines. The Research Domain Criteria (RDoC) classification looks into reductionist explanatory model for illness based on molecules, cells, circuits involved, and background physiology augmented by self-report and paradigm tasks. The RDoC is at infancy level and has to prove the taste of time.
| Genetics Versus Epigenetics|| |
While genetics studies the heritable phenotypical changes due to permanent DNA changes in a given gene, epigenetics encompasses the heritable phenotypic changes which are without any permanent change to the DNA. An example of epigenetic changes is DNA methylation which inhibits the expression of certain genes. The histone modification determines how it wraps the DNA tightly, hampering the readability of the given gene. These epigenetic factors have been found to be affected by many lifestyle issues such as dietary habit, obesity, exercise, substance abuse, environmental pollutants, and stress. In addition, transgenerational inheritance of epigenetic factors has also been seen. Studies on behavioral genetic have found the epigenetic factors to significantly modify the structure and function of neurons. This complex gene–environment interaction further complicates the etiological study of psychiatric illnesses. With gene at the core and epigenetic periphery, many psychiatric illnesses can be explained. While the genetic component remains mostly simple, reducible, fixed, and deducible, the epigenetic environment contributes to the complex, irreducible, variable, and nondeducible. The environment too has variable effect depending on time and nature of impact. Researches have shown that any gene when exposed early to mild stress has led to resilience whereas exposure to chronic stress has produced vulnerability.,,,,,, It has further been seen that giving an enriched environment (more stimulating environment) remediated preexisting vulnerability. These facts magnify the importance of environment in the psychiatric science exponentially., Evidence suggests that the DNA methylation and posttranslational modification of histone affecting myelination, neuronal maturation, etc., have a significant etiological role in schizophrenia [Flow Diagram 2] and bipolar disorder by offsetting the genetic loading.,
| Allostatic Overload|| |
Recent research evidences suggest genes to be a dynamic entity responding to internal and external stimuli starting from conception stage or even prior. Apart from epigenetics, the role of allostatic load has been implicated in the complex nature of the biology. Allostatic load, a protracted overstretching of physiological adaptability, may lead to ill health. Prolonged stress, mental and physical, may cause endocrine dysfunction, autonomic disturbances, immune system impairment, and accelerated cell aging (telomere shortening). These metabolic disturbances may lead to complex physical and mental illnesses (partly through epigenetic process). This brings a new revelation of a composite whorl of illnesses which were earlier deemed as comorbidities. The concept of epigenetics and allostatic load may bring newer importance to role of social gradient in change momentum of morbidity and mortality.,,,
| Antagonistic Pleiotropy: Genetic Trade-Off|| |
Some researchers have studied the genesis of psychiatric disorder with an evolutionary perspective. Their analysis gives emphasis to antagonistic pleiotropy where the researcher surmises that a single gene exerts influence on one productive and one harmful trait simultaneously and therefore the affection of the gene has a positive effect in one dimension and a negative effect in the other. This over the generation is meant to serve the evolutionary protective function, where primacy is given to reproductive success than happiness. While better agility comes at a cost of weaker legs in horses, similarly; the fitness early in life comes with a price of aging early. Anxiety has been equated with smoke detector for life-threatening function (protective function) and depression as self-preservation for others to look after you. The paper also talked about “mutation–selection imbalance” wherein mutation which may cause disorders occurs at more rapid pace than the selection process to eliminate them. Inherent trait complexity is contemplated to be one of the reasons for this increased rate of mutation.
| Internal Representation: Model of World|| |
Psychologists have proposed that the mind yarns an internal model of the world which is complex, dynamic, self-regenerating, active, and ever evolving. In this model, a thought self-triggers other thought. The generation of psychiatric illness has been explained by this model involving the following steps:
- Realm of potentiality – The internal model of mind consequent to an event builds a halo of future possible events and thus shrivels vision to multitudes of alternative possible. This leads to cognitive and behavioral rigidity in thoughts
- Crystallization of distorted belief structure – Daily life events activate particular memory region which is ingredient to next thoughts which activates memory region similar to the above leading to rumination of chain of thought. In addition, some overpowering thoughts or emotions act as attractors leading the train of thoughts to the same end. Finally, our existing belief brings out proportionate emotion in the interaction. This emotion is likely to bring out reciprocal proportionate emotion from the other party in the interaction, further confirming the prior belief. All these phenomena lead to solidification of the structure of belief
- Maladaptive creativity – The dynamic internal world fashions the existing networks into a coherent one which becomes automatic. It develops logical ability of twisting dissonant information into a conforming information
- Pervasiveness of disorder – The distorted model leads to multitude of disorders. The conflict between networks of belief in the internal model brings out dimension of bipolarity or borderline personality. Adjacent possible networks which are likely to have overlap may share common criteria. For example, schizophrenia and depression may share some criteria. This rigid belief system leads to vulnerability which may further reinforce rigidity of the belief, making the disorder pervasive by way of expression (pathoplastic effect) or enduringness of the effect (scar hypothesis).
| Spectral Paradigm of Mental Illness|| |
The word used for rainbow of colors in visible light after passing through a prism can be generalized to group of psychiatric disorders which have disturbance in few defined behavioral paradigms but varies in severity across a broad continuum. For many specific psychiatric syndromes; it has been seen that, there are many variants which though do not meet rigid qualifying criteria for that diagnosis, but are quite similar in characteristics and course. In the given spectrum, similar treatment protocol and management strategies were found to be helpful. The above spectral characteristics do suggest a biological commonality, but whether the variance from mean is because of environment or emergence is still a subject of research. The common spectrum disorder in psychiatry which has taken its place in many a diagnostic/treatment guideline in psychiatry is autistic spectrum disorder, in which the social reciprocity and stereotypic behavior may vary from being deficit to deviant in its spectral characteristics. Studies and clinical experience suggest that the more deficits the social reciprocity is, the higher is the severity of stereotypic action/interests. A classical autism though more severe is more stable in diagnosis and has more defined course and outcome, whereas the continuum farther from the mean has lesser stability in diagnosis and more variability in course and outcome.
| Conclusion|| |
From the above premises, it can be conferred with certainty that the scientific curiosity is unlikely to explain the cause of psychiatric illness based on primarily biological or social phenomenon. The available theories attempt to understand the illness as a varied combination of reductionism and emergence, genetic and epigenetics, stress and the vulnerability, or the core and the periphery. The dynamic interaction of gene–environment and self-generating nature/remodeling of cognition or mind gives a lot of rooms for emergent phenomenon. The time and nature of interaction of environment with gene may yield resilience in one dimension and vulnerability in the other. Mental illness also displays spectral characteristic again suggesting strong biological-environment interface. Thus, the scientific chariot of curiosity cannot make strides on mere two horses to make the essence of the whole, that is, one that of reducible genetics and second that of modifiable environment. The quest will quench with clear understanding of interaction among them, which, like the rein of the horses, impedes or accelerates the process. It is high time we get hold of those reins.
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Conflicts of interest
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