Dear Students!
Our next speaker on the 14th of March will be Bernard Crespi who will talk about: "Evolution of psychoaffective spectrum disorders".
You
will need to read his paper titled:
Please post your comments not later than Tuesday (13th) afternoon!
"The
Evolutionary Etiologies of Autism Spectrum and Psychotic-Affective Spectrum
Disorders"
This chapter presents an argument for aligning autism and psychotic-affective conditions, such as depression, bipolar disorder, and schizophrenia, on a diametric model whereby these conditions represent opposing extremes of a spectrum. These syndromes or disorders (rather than “diseases”) can be viewed in terms of under- or over-development of social cognition and affect in the context of their evolutionary, biological, genetic, neural, and/or psychological causes with possible environmental involvement. Autism, for example, can be considered a maladaptive underdevelopment of social brain phenotypes; some hypotheses assert that asocial cognition and repetitive behaviors may arise as a compensatory tradeoff to specific neurodevelopment or even as a coping defense to challenging symptoms such as increased perceptual sensitivity or stress from social-cognitive tasks. In contrast, schizophrenia, bipolar disorder, and depression may represent an over-developed adaptive system for assigning salience, or causal meaning, to external and/or internal stimuli. By this view, hallucinations can be understood as an over-developed salience to inner thoughts and speech, and manic and depressive episodes may be symptoms of faulty homeostatic regulations of emotions underlying goal pursuit. When these disorders are characterized in a diametric fashion, studying one disorder may provide reciprocal insight into the other. Cognitive-behavioral treatments therefore should explore enhancement of phenotypes related to social imagination, motivation, salience, and goal-seeking in autism but reduction and regulation of these phenotypes in psycho-affective disorders.
ReplyDeleteThe Evolutionary Etiologies of Autism Spectrum and Psychotic-Affective Spectrum Disorders
ReplyDeleteThe article compares the evolutionary etiology between autism and psychotic-affective spectrum disorders such as schizophrenia, bipolar disorder and depression. Autism is often represented as an underdevelopment in social cognition while psychiatric disorders such as schizophrenia on the other hand are classified as over-development in social cognition albeit difunctionally. As a result, it becomes increasingly complex to propose a clear diagnosis for it. Diseases which can be examined through some physical symptoms are relatively easy to provide a diagnosis for, but psychiatric disorders often have multiple overlap of symptoms, also the exact cause which triggers these disorders are unknown or there exist very little understanding about it. Paper gives out six different reasons where maladaptations may arise and continue to sustain itself in the population. These range from ‘standard’ deleterious alleles to body masking to prevent abnormal body conditions. The later seems rather interesting as there may exist a situation where this actually helps the person suffering. One of the situation which highlights this condition is discussed in the article in which body performs repetitive behaviors just to avoid sensory arousals. So given the aforementioned conditions, it is not possible to define psychiatric disorders such as autism, schizophrenia etc as diseases.
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ReplyDeleteJessica Yoo
DeleteThe Evolutionary Etiologies of Autism Spectrum and Psychotic-Affective Spectrum Disorders
Crespi explicates how important genetics, neuroscience, and cognitive science backgrounds are in understanding the causes of autism and psychotic-affective disorders. Autism and psychiatric disorders can be viewed from evolutionary point of view of the social brain. While autism stands as “under-developed” social brain that may be caused by multiple influences, psychotic-affective spectrum disorders such as schizophrenia and depression stand on the other end as “over-developed” social brain. It is central to understand that bipolar disorder and depression are affected by emotion and mood which are adaptive to different situations. Autism and psycho-affective disorders may be related in which they both partially share social deficits such as in social cognition, but also are completely different in a way that stand as under- or over-development from evolutionary perspectives. Because autism and schizophrenia have been found to share some genetic risk factors, this limits early diagnosis of schizophrenia and instead be falsely put under a category of autism due to current DSM structure and this possibility should always be taken into consideration. Further research in medicine and psycho-analysis will be able to provide a new model of disease that incorporate psychiatric standpoint.
The standard medical model of today describes disorders in terms of their dysfunction. Therefore, mental and psychiatric disorders have also been described similarly. It is possible that what we describe as disorders of the brain are in fact evolved mental adaptations. What we know currently about the cause of psychiatric disorders is grounded in evolutionary biological research on deleterious alleles, mismatched environments, extremes of adaptations, trade-offs, conflicts, and defenses mistaken as symptoms. The occurrence of autism and psycho-affective disorders (i.e., schizophrenia and bipolar disorders) can be explained by several evolutionary biological theories associated with this research. One such hypothesis, the diametric hypothesis, states that biological systems such as social cognition can vary and be pulled in opposing directions of expression, thus the extremes of autism and psychiatric disorders. With our expanding knowledge regarding disorders of the brain, many have evolved from considering them as diseases, to disorders, to differences in very recent years. Our continued progress in focusing on these conditions from an evolutionary biological perspective can continue to aid our understanding.
ReplyDeleteIn this chapter Crespi argues that autism spectrum disorders and psychotic-affective spectrum disorders (e.g. schizophrenia and bipolar disorder) represent conditions on opposite ends of the spectrum of social development and cognition. He argues that the medical model of mental disorders—the effects of which are seen in the DSM—is an inadequate framework for studying these disorders. Instead, he posits that these mental disorders are best understood in the context of evolutionary mechanisms. Crespi outlines several research findings that can help explain mental disorders in evolutionary terms.The primary evolutionary finding is that, with a few exceptions, the genetic mutations that are associate with increased risk for mental disorders are widespread in the general population, and in some cases are associated with positive traits in the family members of people with these disorders. Thus, it is possible that these traits may have been under positive selection pressure. If these genes had overwhelming deleterious effects to fitness, they would be much rarer among the population since they would have been weeded out by natural selection. Additional research has found that some mental disorders are associated with mismatched environments and or extreme forms of adaptation. In other words, its possible to have too much of a good thing, and what might be beneficial in one context may be deleterious in another. Further research has found that certain phenomena-types are associated with trade-offs—certain traits positive traits can over-develop at the expense of other positive traits. Furthermore, certain symptoms of psychiatric disorders may not be core symptoms, rather may reflect natural coping mechanisms in response to other symptoms.
ReplyDeleteCrespi argues that these findings are particularly illustrative of the complementary relationship between autism spectrum disorders and psycho-affective disorders. While both these types of disorders are understood to be related at some level, Crespi claims that their relationship is one of diametric opposition rather than overlap. He argues that empirical evidence suggesting overlap is flawed, because it comes from blunt measurement instruments that show that both disorder types have a higher degree of impairments in social cognition. Instead, he argues that their diametric relationship can be understood in terms of quality of impairment rather than quantity. Understood this way, both disorders could reflect different evolutionary responses to the development of social cognition—which autism spectrum disorders reflection an under-development and psycho-affective disorders reflecting an over-development.
Because many psychiatric conditions cannot be objectively and unequivocally quantified (the goal of the standard medical model) due to a lack of understanding regarding their etiology and underlying mechanisms, their "diagnosis" is often an inference based on the presence of a clustering or pattern of symptoms. However, evolutionary biology provides an alternative perspective to evaluate dysregulation of adaptations within the human cognitive and affective systems. Utilizing this viewpoint, Crespi suggests that psychiatric conditions are caused by deleterious alleles, mismatched environments, extremes of adaptations, tradeoffs, conflicts, and defenses mistaken as symptoms. Additionally, Crespi proposes a diametric model in which autism and psychotic-affective conditions, including schizophrenia, bipolar disorder, and depression, are extreme opposite ends of a continuum reflecting social cognition, affect, and development. Autism is viewed as the extreme underdevelopment social cognition while psychotic-affective conditions are viewed as its extreme overdevelopment. This model enables the utilization of information from the study of one disorder to be applied inversely to the other which could result in significant advancements in the discovery of etiologies as well as the development of effective treatments for each of these conditions.
ReplyDeleteCrespi assesses the evolutionary developmental biology of mental disorders with a focus on autism. By understanding the underlying brain functions of mental disorders, there could be more clarity in the evolution and treatment. The chapter highlights six major areas of findings for the evolutionary causes of mental disorders: deleterious alleles, mismatched environments, tradeoffs, conflicts, and defenses mistaken as symptoms. However, the major focus is autism and the need to consider overlap/comparison with psycho-affective spectrum conditions (i.e. schizophrenia, bipolar disorder, and depression). Autism is defined as a disorder characterized by social and communicative disturbance. It is important to understand the social cognition of typically developing people before we can really understand the “dysfunction” in this area in autism. Crespi describes deficits in social cognition as maladaptive extremes of an underdeveloped social mind. Thus, there may be an explanation in reduction or loss of some of the systems necessary for social brain development.
ReplyDeleteI found Crespi’s statement that psychiatric disorders were not “real” very interesting. It does make sense that because we do not understand all of the underlying brain functions involved with mental “disease”, we cannot truly provide sufficient evidence for causes and patterns. In terms of neurodiversity, it seems that these constructs are subjectively determined. This type of thinking reminded me a great deal of the talk Dr. Varga gave early this semester about the philosophy of psychiatry in labeling something a disease when it is based on societal norms. How do we objectively study conditions that have potentially been artificially deemed as disordered? Crespi seems to agree with Varga that disorders such as autism, bipolar disorder, schizophrenia, and depression cannot really be referred to as diseased. However, Crespi supports this statement by comparing our understanding of medical models of disease (e.g. such as the example medical model of diabetes) to our understanding of human mental disorder. There is a lack of focused etiology in mental disorders that does not neatly fit into the model because more needs to be know first.
"The Evolutionary Etiologies of Autism Spectrum and Psychotic-Affective Spectrum Disorders"
ReplyDeleteThe article has showed the differences between Autism Spectrum and Psychotic-Affective Spectrum via the evolutionary etiologies. While autism has been considered as underdeveloped social cognition that the human social brain does not complete its usual developmental trajectory, psychotic-affective conditions, mainly schizophrenia, bipolar disorder, and depression, are dysfunctionally over-developed aspects of social cognition. There are six causes that represent the 'ultimate' sources of these conditions: deleterious alleles, mismatched environments, extremes of adaptations, tradeoffs, conflicts, defenses mistaken as symptoms. They converge in their emphases on determining what evolved genetic, developmental, neural, cognitive and emotional systems are altered, and how they are altered, in psychiatric conditions. The author also implicated risks for human mental disorders have evolved: autism, schizophrenia, bipolar disorder, and depression cannot justifiably be considered as 'diseases' under standard medical models of disease due to inadequate understanding of the neural-system adaptations subject to maladaptive alteration. Overall, these studies and reasoning here again confirm evolutionary approaches in medicine, and psychiatry help guide research and treatments to right directions.
This paper uses many studies and researches to give a review on the mental disorder including autism, schizophrenia, bipolar disorder, and depression. Author recommenders some new research directions on the view point of evolution.
ReplyDeleteAuthor used the standard medical model to raise a critical issue: the way we treat those mental disorders by objectively defined, which a way we treat diseases is. But mental disorder is not a disease from either definition, or standard medical model which needs verifying the cause, feature, and fully understanding of the disorder. We may have studied a lot on those mental disorder but we have to face the factor that we haven’t dig out how and why those mental disorder happen.
Later, author took the core of the evolution selection opinion, and expended to mental, behavior and action. Originally, the evolution selection concerns more about the survival and reproduction. Author believes that the mental behaviors also have the same purposes of survival and reproduction. From other paper, we have known that the reproduction rates of mental disorder shows negative values (beside depression). From genetics and neuroscience, author raised six potential hypothesizes: 1. Deleterious alleles; 2. Mismatched environments; 3. Extremes of adaptations; 4. Tradeoffs ;5. Conflicts; 6. Defenses.
Following, author uses those six hypothesizes to analysis the reason, or causes of the features of the mental disorder. Based on the understanding of the disorders, author divided them into two groups, autism spectrum (underdeveloped social cognition) and psychotic affective spectrum (over-developed social cognition) including schizophrenia, bipolar disorder, and depression. Standing on the viewpoint of evolution, author raise a diametric model which support many data and evolution explainations.
My questions:
1. Why is mental disorder linked to unhappiness? Disorder may not cause a patient painful or unhappy but the wrong communication way between autism and normal people? (I agree with the reproduction viewpoint somehow)
2. Is tradeoff effect obvious among the people? Is it an axis, or multi-dimensions?
3. Natural selection is adopt when object is in a nature. And human now are out of the nature (we said human is on the top of the food chain.) We have the ability to change the society. How do you improve the evolution selection and prove the importance of “Extremes of adaptations”?
Lijia Wang