In mental illness, let’s go beyond nature v. nurture to look at what interferes with the brain’s function

AmindbodyBased on her ethnographic study of psychiatric residency programs, anthropologist T.M. Luhrmann concluded psychiatry is “of two minds”: one “mind” emphasizes the role of neurochemistry, while the other “mind” places more importance on the context of our suffering, including relationships past and present.

Identifying the origins of mental illness likely depends on both interpretations. There is an undeniable organic component to mental illness, just as psychological and social conditions are inexorably linked to mental well-being. But like the Democrats and Republicans, these two approaches are often pitted against one another, often leading to that old, tiresome nature versus nurture debate.

Unfortunately, in a world of limited resources, including limited time, the implicit guiding question — Where should we place our focus? — naturally divides our attention. Is it helpful to explore genes and neurobiology in our efforts to reach best outcomes? Or is it better to explore the social conditions that contribute to mental disorders? Unfortunately, much like U.S. politics, the treatment of mental illness often is derailed when such questions become fodder for polarizing arguments that serves allegiances and professional agendas more than persons in the throes of mental suffering.

Instead of worrying if nature is more influential than nurture, perhaps it would be more helpful to identify what counts as optimal functioning for the brain. Perhaps we could then focus on the value of combining information, thus leading to better outcomes rather than increased competition (and often, market share). I think the significance of function often gets overlooked because we aren’t adept at looking at any issues from multiple levels. Although the term biopsychosocial was coined to address the issue of scale and focus in the treatment of mental illness, it often feels piecemeal in approach.

How might we identify the causes of mental illnesses in ways that address their biological, psychological, and social aspects without parodying the impact of any of them?  Furthermore, what stands in the way of answering such a seemingly straightforward and important question?

More than any other arena of healthcare, the mental health field is paralyzed by politics, disciplinary boundaries, and financial stakes competing to define the disorders it treats and studies. I have wondered what it would be like for all of us who either work in the field or receive treatment for a mental disorder (a Venn diagram of these two groups would show a big overlap) to restart our quest for mental health and well-being with the very simple question:

What is the function of the brain?

With this question, I think we might begin treating the brain like any other organ of the body, and not according to its current exalted status. Appropriate treatment would “simply” mean returning the brain to its optimally functioning state. I believe this question could also encapsulate the complex relationship between biology, self, and society that complicates understanding the nature of mental illness as well as identifying best treatments.

Typically, something is perceived as a disease or trauma when it interferes with an organ’s proper functioning. By knowing the function of an organ of the body, it follows that healing that organ involves returning it to its homeostatic, functional state. Thus, what counts as disease or trauma are those things that interfere with normal functioning. For example, we know the function of the heart is to repeatedly and continually pump blood through the blood vessels, and anything that interferes with this process would be identified as disease or trauma. Similarly, the functions of the stomach include storing food during a meal and breaking down food particles into molecules small enough to be absorbed by the small intestine.  Whatever interferes with these functions is treated as disease or trauma.

We can identify the functions of every major organ of the body — the lungs, the skin, the intestines, the skeleton, the immune system — and with this knowledge, both diagnose and treat the causes of disease or the effects of trauma. Whereas there may be many paths to the cure, there is nevertheless a shared understanding of how the organ is meant to function. This simple approach seems to evade the mental health sciences, and I wonder if this is because there is a lack of agreement about the function of the brain.

We know the brain is part of the central nervous system, which functions like a command center for the rest of the body as well as gathering sensory information from the environment. The neurochemical model of mental illness relies heaviest on this understanding of brain functioning, particularly given its focus on neurotransmitters. Having a well-functioning central nervous system certainly seems central to mental well-being, yet it is also likely only one contributor to mental illness, and cannot adequately account for the psychological and social impairment also associated with mental illnesses. Although this model of mental disorders is not necessarily wrong, it nevertheless is too limited in scope to grapple with the myriad phenomena we associate with mental disorders.

An alternative model of the brain has emerged with research into the neurobiology of trauma as well as research into the different regions of the brain. With this model, the brain is understood more in terms of the functions of its components and adaptation to environmental conditions, especially the environments created through our relationships with significant people in our lives. This is an important change in scope from the biochemical model of mental illness that seems to rest on the “command, control, communicate” metaphor that has dominated information systems thinking since World War II.

In contrast, the neurobiology of trauma model examines how specific areas of the brain — often depicted as three primary regions: the cortex, limbic system, and brain stem — take part in the process of gathering information from the body and the environment, synthesizing this information, and then acting in accordance with often implicit needs or desires. In particular, two dominant action tendencies are thought to organize how the brain functions, which also correlate with two dominant environmental conditions:

  • conditions of attachment and normal daily activities, and
  • conditions requiring defense (i.e., fight, flight, freeze, submit, cling).

From the perspective of the neurobiology of trauma, sociality, and the capacity to engage with others in meaningful and pleasurable ways, is inversely related to the amount of traumatic stress a person experiences. Too little of the conditions that contribute to sociality, along with too many of the conditions that activate defense responses (including low levels of chronic stress), lead to poor mental functioning. And yet both functions — surviving in states of peace and in states of defense — are necessary functions of a healthy brain. (Thus an added benefit of the neurobiology of trauma model is that it replaces notions of pathology with notions of adaptation.)

The neurobiology of trauma model of the brain can also incorporate the functions of the central nervous system associated with the biochemical model of mental disorders, especially when the primary function associated with the brain is this concept of sociality. When the brain is seen as primarily a “social” organ, it seems to have two main functions:

  1. to communicate with the rest of the body in the creation of a coördinated response to stimuli (creating an ‘internal’ society of sorts); and
  2. to communicate with the world in the creation of a self among others selves.

When the primary function of the brain is seen as sociality — both within our own psyches & bodies and with other people — mental illness could then be simplified to include

  • interference with the capacity for internal communication that contributes to authentic self-care;
  • interference with the ability to be a self among others, and thus feeling relaxed and safe in the presence of others; and
  • interference with the capacity to maintain meaningful and supportive relationships.

Just as there are many ways for the heart, stomach, or any organ to be diseased or traumatized, there are many ways for the brain to lose functionality. Impairment does sometimes result from genetic predispositions, although typically in combination with physiological stressors such as exposure to toxins, exposure to bacteria and/or viruses, poor diet, high levels of stress, and injuries that alter the physiology of the organ or impairs its normal development. Also included in these physiological environmental stressors are traumas such as adverse childhood experiences, assault, combat, and other situations where people hurt people, thus not only overly activating defense responses, but also altering the capacity to function as social beings.

Both nature and nurture are undoubtably contributing causes to mental disorders. But perhaps we should think of them as either less or more relevant depending on which lens best helps people regain functionality — both in terms of their inner and outer sociality.

Another way of thinking about this would be in terms of integration. Feeling internally integrated lessens the sense of internal fragmentation. And integration is central to mental well-being. Feeling internally fragmented demands a lot of energy and attention, and often leads to isolation and limited integration with the larger community, hence also limiting the capacity for sociality.

Lacking the capacity for sociality seems central to the suffering associated with mental disorders, irrespective of the cause. And isn’t the reason we have any type of healthcare is to help people overcome suffering? Sometimes when overloaded with competing theories, professional agendas, and the potential for large profits, we lose sight of this otherwise straightforward goal. Yet if we can agree on the primary function of the brain, I think we can also be more astute in our choices about what counts as best treatments.

© 2014 Laura K Kerr, PhD. All rights reserved.

Laura K. Kerr, PhD, IMFT is a mental health scholar and registered marriage & family therapist intern in the San Francisco Bay Area. For more information, visit her website.

9 responses

  1. There is a tremendous number of things in mental health which we tend to grossly oversimplify in the interest of making treatment appear easy and appealing, which ends up clouding more issues in than it clarifies. The nature vs. nurture debate is one of those things. Therapy vs. medications is another one. Many of my own patients entrench themselves in the “I only want therapy” or “I only want meds” camp and then neglect the value of the other side of treatment. We need a more balanced and nuanced approach to many of the things we do. Thanks for this article.


    • Thank you so much for your insights. I like your recommendation of a “more balanced and nuanced approach” to mental health treatment. And as you suggest, to create such an approach will mean moving beyond simple and quick solutions. It takes time to heal, and treatment has to be tailored to the unique individual.


    • Thanks so much for sharing! And yes, I agree with the article; it is inspiring that trauma-informed care sees love as central to the “cure”.

      Have you joined ACEs Connections? You might enjoy having a blog to share with like-minded folks. We certainly would benefit from your knowledge and interests.


  2. What a ‘terrificly’ thorough look at the brain. I enjoyed every morsel. I’d just like to add that the brain’s ABILITY to function at the different stages in our development needs to be better understood and respected. What gets me all worked up is when three year olds today get diagnosed with SAD, when developmentally they are supposed to be shy and attached to and looking to their primary caregiver in their life. Stranger protest is developmentally appropriate. Mother Nature knows what it is doing when it comes to some of our limitations in our early years. After all we are the slowest of all mammals to reach the point of maturity…should we be so lucky do so :0)


    • These are such important points. I recall in a Surgeon’s General Report (1999?) a discussion of the importance of resisting even diagnosing children and adolescents with mental disorders because of the steep developmental trajectory in early life. What is often a ‘problem’ at one stage is then ‘grown out of’ at a later stage. I also read a recent article that discussed research on Prozac use in adolescents. This research showed that teens who used Prozac often had more mental health issues later in life than teens with similar problems who weren’t given medications.

      Thank you for your reply.


  3. Some of the neurobiological “differences” that immediately get pinned as “abnormalities” by so-called biological psychiatrists are nothing more than conditioned responses that are adaptive to environments, such as growing up in a chaotic family of origin filled with mixed messages going every which way. Neural plasticity and epigenetics have already given us a lot of answers about the interaction between nature and nurture.

    Another big problem here is that all mental disorders are often lumped together as if they were all the same. Some like schizophrenia do indeed appear to be every bit as much of a brain disease as Alzheimer’s disease – not that psychological stress can’t make a brain disease worse, mind you. Other mental disorders (e.g. borderline personality disorder) are behavioral disorders. To say that there is a biological component to them is kind of redundant, since there is a biological component to all behavior, including me writing this reply.


  4. Recent research by Susana Herculano-Houzel has determined that the whole brain contains roughly 86 billion neurons. 69 billion of those 86 billion are found in … the cerebellum, primarily associated with motor movement. Add in the neurons in the motor cortex and you find more than 80% of the brain’s cells are devoted to moving the body. Cambridge neuroscientist, Daniel Wolpert makes a strong argument that this is the brain’s primary function. “Recovering neurologist” Bob Scaer, author of The Body Bears the Burden and The Trauma Spectrum believes that it is the Freeze Response – those times when the body is unable to physically move, that is the primary contributor to PTSD. I would hypothesize that body immobilization is what often makes ACEs often have the lifelong impact they do.


    • Very fascinating research. I think Herculano-Houzel’s research relates in interesting ways to what we know about the evolution of language, and how so many of the words we use originated in gesture. Yet I am also thinking about the amygdala, and how teeny tiny it is relative to other brain structures, and yet can so easily override the entire neurobiological system when there is a sense of danger. How much does size and number matter in relation to function? I don’t know. What I like about this research, however, is the connection between brain and body that it makes — and another nail in the coffin of body-brain dualism.

      I agree with Scaer about the significance of the Freeze Response for posttraumatic stress. And I find it even more interesting how you have put these two researches side-by-side — Herculano-Houzel with Scaer’s. I imagine there is much to explore between them!

      Thanks so much for your reply.


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