Why Depression isn’t about Dopamine and Serotonin

“Psychiatric Disorders as Brain States”

When you go to a psychiatrist they don’t take scan your brain and they don’t monitor biological markers to diagnose you. They go through a checklist of questions about your behavior. Even though patients and doctors only interact with mental disorders through behavior, many people describe their own mental health in terms of neurobiology. Instead of depression being about a way someone feels, it’s reframed as a problem with serotonin levels. Though this “neurobiologicalization” of psychiatry may in some way reflect a better scientific understanding of the disorders, the explanations are likely to be too simplistic. Instead, explaining mental disorders in terms of neurobiology tends to lead to misleading, but somewhat scientific sounding, explanations. So, why do we use this neurobiological language to describe our feelings?

The different psychiatric terms that are used to describe mental disorders are complicated because there are so many different dimensions that influence how they are used. Take a relatively well accepted illness like “Bipolar disorder” (BPD). Within psychiatry, BPD refers both to a static set of behaviors that someone needs to meet to be “bipolar” and to a large set of neurobiological markers that are met by all those who are supposed to be classified under “bipolar”. Within the people who are labelled “bipolar”, “bipolar” is characterized by how they are classified, how they actually act, and how they experience the world. So people labelled as “bipolar” not only have the third-person data and the psychiatric classification, they also have data about what it is actually like to have the disorder.

On top of all of this, the term “bipolar” has significant historical, cultural, and institutional context. It has not always been named. It is described in slightly different ways by all the different institutions that are trusted to define these terms (e.g. APA with the DSM). And each institution has evolved in how they characterize the disorder based on the era and the scientific information and political nudgings at the time of writing.

In The Looping Effects of Human Kinds, Ian Hacking argues that our understanding of behavior is dependent on what he calls ‘human kinds’ which are special terms developed out of the classification and quantification of social science that are used to describe how and why people act the way they do. The crucial part of his argument hinges on his distinction between ‘human kinds’ and ‘natural kinds.’ Natural kinds are the scientific terms that refer to the actual structure of the world without any consideration for the actions or interests of humans. When physicists are talking about “electrons” they are referring to an actual distinctive grouping of material in the world, particularly negatively charged particles that surround the nucleus of atoms. In this case, “electron” is a natural kind. Hacking also calls them ‘indifferent kinds’ because they supposedly have no relation to the interest and social structure of people. In contrast, ‘human kinds’ are ‘interactive kinds’ which have interactive effects with what they classify based on how the term creates expectations for the classification. He calls this interaction, “looping effects.”

One example of a possible human kind is ‘homosexuality’. ‘Homosexual’ is a relatively new term that is used to classify someone who has sex with people of the same sex. What is not obviously problematic is that the term seems to pathologize the people who are given the classification. It in some way makes the act an essential or ‘natural’ part of who they are. Humans have been having sex with people of the same sex for a long time,, but the term itself, and the entire subculture that developed under it, did not come into fruition until modern psychology made the classification. The crucial part for Hacking is that the development of this term influences the people who are called “homosexual.” In some way it may influence them to fit the term ‘better’ by behaving in ways that more clearly identify them as ‘homosexual.’ He extends this to a lot of different psychiatric disorders where he thinks that the scientific classification of the term helps actualize what the term refers to. So, if I was labelled as “ADHD” or “Bipolar” the labels themselves may affect how I act, pushing me in some ways to conform to those classifications.

Ian Hacking develops his interpretation of psychiatry in Making Up People. The general question of the article is “should, how, and why do we ‘make people’ through our various psychiatric classifications?” It revolves around this historical, Foucauldian idea that much of the psychiatric and behavioral classifications that we are so familiar with — multiple personality disorder, perversion, homosexuality, major depressive disorder, nymphomania — are relatively new classifications that came out of the scientific psychiatry that started to develop in the 1800s but didn’t really come into its full taxonomizing glory until the early 1900s (Hacking, 2006). Take multiple personality disorder (MPD). It is a relatively new clinical term and it is contentious even within psychiatry. To Hacking, you need to ask three questions about MPD. (1) Does MPD refer to any relevant and generalizable behavioral grouping that have always existed? (2) Why was the term MPD developed? (3) And how has the term influenced the behavior of those classified under MPD? This sort of historical perspective can be helpful and it quickly gets to a central problem within philosophy of psychiatry. Namely, are psychiatric kinds natural kinds? To Hacking, the answer is clear. Psychiatric kinds are not natural kinds because the classification itself has such a huge impact and “intensifying effect” on the behavior of those classified.

So far, Hacking has given us a strong social interpretation of psychiatric kinds that relies heavily on the historical analysis of Foucault. In Psychiatry in the Scientific Image, Dominic Murphy presents a strong opposing view to Hacking that places much more emphasis on the possible progress of psychology and neuroscience in describing human behavior. He focuses on the theory, problems, and motivations of the scientists and clinicians who first developed the clinical classifications that Hacking sees so many issues with. He calls this set of classifications the medical model of psychiatry (Murphy, 2012).

To a strong proponent of the medical model, psychiatric kinds are natural kinds which describe important and generalizable ways in which neurobiology manifests itself into similarly generalizable behavioral groupings in the real world. For example, MPD within this model doesn’t just describe a set of behaviors, it implies underlying neurobiological processes which instantiate all the relevant behavioral patterns. Murphy believes that some revision may be in place for some of the classifications that have been developed over the last 200-or-so-years of psychiatry. Many of these classifications, he argues, rely too much on behavior which can be heavily influenced by social norms and possibly even some of the problems brought up by Hacking. Although he may not be responding directly to Hacking, there could be ways in which he may agree with him on the heavy social and cultural influences on a psychiatry that only draws its classifications from supposedly generalizable behavioral groupings. So although there is some convergence between Hacking and Murphy about an overly behavioral characterization of psychiatric kinds, Murphy’s central claim is that the role of understanding and reforming these psychiatric classification relies on a strictly scientific process where neuroscience and psychology work to either vindicate or eliminate these different psychiatric kinds.

Murphy is also quick to point out that a psychiatric kind’s absence in history does not actually say anything about whether it is real. For instance, although we have very good reason to believe that “electrons” have always existed, they were not characterized or explained until recently. Their absence in the historical record, however, is not taken to be a strike against the empirical validity of them as real natural kinds. Much of Murphy’s aspiration for psychiatry rests on this hope, that science progresses and that the historical mischaracterizations of current psychiatric kinds don’t say anything about the natural kind status of any of them.

Mental disorders are complex and evolving categories. Hacking wants us to be very cautious about how the classification of the psychiatric kinds can influence and/or reinforce the actual instantiation of them. While I think he has made a good point about how contextual these terms can be, Murphy has given us some worthwhile reasons to move past an entirely socially constructed view of psychiatric kinds. For one, the looping effects operate mainly on people who already know or understand their disorder or their possible disorder, but they don’t clearly explain the characterization of people who have no prior understanding. For instance, if I had no idea what bipolar disorder was, but I was diagnosed as being bipolar there would have been no way for me to have “looped” into fitting the classification. Perhaps the classification may intensify how I conform to it after diagnosis, but (1) it doesn’t explain the existence of the behavioral and neuroscientific characteristics that first placed me into the classification and (2) whether the classification itself intensifies conformity becomes a strictly empirical problem.

Going along with Murphy, if we accept that the science has made progress in characterizing various natural kinds that have not previously been described, then we can both accept that looping effects and history may have some important impacts on psychiatry without thinking that they give us reason to completely reject the notion that various mental disorders do name and explain real natural kinds which exist independently of their classification.

There is a very big divide between the expert use of scientific terms and the social/folk use of the very same terms. We need to untangle the various issues that arise when taking on new neuroscientific terms to explain our thoughts, emotions, and disorders. We are starting to no longer see mental disorders like addiction as something inherent to certain activities or as something in the control of the individual, they are now more about abstract scientific kinds like “serotonin” or “dopamine”. In a way this should not be too surprising. It is well aligned with the view of scientific progress put forward by Murphy: our brains just do everything that makes us who we are, and it should not seem odd that something in the brain will be able to partly explain what’s going on in our actual lives. But it is not clear that any of the “pharmaco-therapeutics” work anything like how they are colloquially described and marketed. For instance, the scientific community isn’t completely sure how SSRI’s (selective serotonin reuptake inhibitors) work and, despite their name, there is contention about how they even act on serotonin. On top of that, even if they did act on serotonin, we don’t have a very good explanation for how this is related to our behavior. Rather, it seems like much of the neuroscientific-sounding explanations of the pharmacodynamics are overly simplistic and barely informative about the actual mechanism. However, whether they are true scientific explanations may not actually matter, what’s interesting is how and why these neuroscientific explanations are so readily taken up and used despite their obvious inaccuracy.

While psychiatric kinds do have obvious social and historical influences, we should be skeptical about thinking that they are solely social constructed. It makes sense to at least begin to investigate the possibly “natural”, distinct neurobiological bases for psychiatric kinds. But again, the problem with a non-expert neurobiological explanation of psychiatric kinds is that they are often simplified to the point where they have little resemblance to the science, and, even if there were detailed and coherent explanations of the neurobiological functions, it is not clear that this would function well as a social explanation of individual mental states. As much as I’d like, explaining my anxiety in terms of cortisol and all of the other neural components to that anxiety isn’t yet very helpful for me in understanding my feelings and it still doesn’t work very well to tell others how I am feeling. “Anxiety” just still tends to function better.

I suspect that the simplistic social use of neurobiology to explain mental health is partly due to the fact that it (1) seems to take responsibility away from agents in social contexts and (2) it gives agents an outside, biologically-grounded justification for why they feel and act the way they do. So although, from an expert’s view, these mental disorders have real historical, cultural, and scientific meanings, this neurobiological simplification is widely taken up, not necessarily just because it is somewhat true, but because it has tremendous value for the people with mental disorders — it allows them to at least emotionally dissociate from behaviors that they may not necessarily have control over.

Psychiatry has a long and evolving history. Though there is something to say about the cultural, historical, and political failings of the field over the last 200 years, the more recent, medically-focused development of psychiatry has led to a modern psychiatry which may revise its definitions with a renewed focus on neurobiology. And while this neurobiologicalization of the field seems to more closely align with the reality of the natural world, the social uptake of these neurobiological explanations of mental disorders is problematic because it often oversimplifies the disorders and likely doesn’t have considerable relation to the actual work of the experts in the field. On top of that, these neurobiological explanations seek to largely replace attitude and emotion talk which are already very successful tools to explain behavior. So while it may be the case that neurobiology is the best way to actually understand psychiatric, the possible truth of the neurobiological account is not a sufficient explanation for why the public takes up the account and chooses to use the account’s evolving terminology to replace emotion talk: how depression is now less about being depressed and more about “serotonin, etc.” I think the neurobiological account is taken up because it positively affects existing social identities and relationships by lessening the responsibility of people over their behavior. For instance, when thinking about the heroin addict or schizophrenic — as opposed to prior times where their disordered behavior may be explained in terms of God’s wrath, their relationship with their mother, or a weakness of will — they are now understood as people who have little control over neurochemical imbalances. In this way it functions to not only improve social understanding of their disordered behavior, but it may even help people better cope with the possibly deterministic nature of it.

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Math Teacher writing on Philosophy and Policy and Science and Education and Other Things. coreykeyser@gmail.com

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