Is depression a brain disease ?

depression_pic.jpgA kuro5hin.org article on ‘Demystifying depression‘ gives an excellent account of the experience of depression, but uncritically repeats some common assumptions about the condition – namely that it is a ‘physical illness’ caused by ‘low serotonin’.

Despite the familiarity of these claims, both are problematic.

The article by an author entitled Name of Feather takes a comprehensive look at clinical depression, and vividly describes the experience at the heart of the author’s malady. It is also abound with good advice, such as seeking the help of a competent well-informed professional early in an episode.

It also attempts to describe what causes depression but makes several points that are often repeated as facts, but have surprisingly little support, or are highly controversial in the scientific literature.

Depression as a physical disease

The author asks us to “forget purely psychological explanations of the illness”, “clinical depression is a physical illness” and claims that dualism, the idea that mind and brain are separate entities, is responsible for this false view of mental illness.

On a pragmatic level however, clinical depression is defined as mental phenomena. The criteria used by psychiatrists for diagnosing a Major Depressive Episode lists ‘depressed mood’ or ‘loss of interest or pleasure’ as the core feature and the majority of the additional features are purely psychological in nature.

If we want to believe that depression is a purely ‘physical disease’, then we could in fact feel pushed into dualism. Perhaps thinking that depression affects the brain and somehow the separate mind reacts to this impairment of thinking or emotion to produce the conscious experience of depression.

More likely, the view that depression is purely a physical illness reflects a school of thought known as epiphenomenalism, which argues that the mind has no causal effect at all, and is just the subjective experience of our brain at work.

However, both of these theories are roundly rejected by the majority of contemporary neuroscientists, psychologists and philosophers.

The most common view is that mind and brain are exactly the same sort of thing, but described at different levels of explanation – a school of thought known as property dualism. In other words, the mind is changes in the physical structure of the brain, and changes in the physical structure of the brain are the mind.

To make an analogy, no-one would deny that the economic system exists in the physical world, but to try and explain unemployment in terms of atomic physics would be folly, as would trying to solve economic problems by using a particle accelerator. In a similar way, we can accept that the mind and brain are both based in the physical world, but explaining the mind, or mental illness, purely in physical terms, may not always be appropriate or useful.

In a recent article for the American Journal of Psychiatry psychiatrist Kenneth Kendler cautions against exactly these sort of simple ‘physical’ explanations for mental illness and argues that comprehensive explanations and treatment will have to involve both psychological and biological theories.

If the logic of this argument is not convincing enough, recent studies have shown that psychotherapy has a measurable influence on brain function, with the neuroscience of psychotherapy now becoming an exciting complement to the vast amount of research on the psychological effects of physical treatments.

Depression as an illness of ‘low serotonin’

In Name of Feather‘s article, he or she suggests that depression is caused by exhausting levels of serotonin in the brain. Unfortunately, there is little support for this simple theory.

If depression is nothing more than low serotonin, drugs that specifically lower serotonin levels in the brain should lead to depression or at least low mood. Studies which have tried this in both healthy participants and depressed patients show remarkably little effect on mood, with a mild dysphoria being the only occasional effect.

Furthermore, drugs which increase serotonin levels in the brain typically do not start having an effect on mood for several weeks, despite affecting serotonin levels immediately.

It is likely that serotonin plays some role in mood, but in a recent article for Nature Reviews Neuroscience, neuroscientist Eero Castrén criticises the oversimplified view of depression, stating:

Over the last few decades, the view that depression is produced by a chemical imbalance in the brain has become widely accepted among scientists, clinicians and the public.

However, during the past decade, several observations indicated that there might be an alternative hypothesis to the chemical view of depression. This network hypothesis proposes that mood disorders reflect problems in information processing within particular neural networks in the brain and that antidepressant drugs and other treatments that alleviate depression function by gradually improving information processing within these networks

It is notable that Name of Feather does mention an information processing approach to understanding depression, although it is important to note that this theory is a more complex and nuanced explanation than a simple ‘low serotonin’ theory can support.

Should we be cautious of purely biological theories of mental illness?

One motivation sometimes given for stating that mental illness is a purely ‘physical disease’ is to draw parallels with physical ailments, to try and make mental illness less stigmatised. Nevertheless, some research has suggested that purely biological explanations might have the opposite effect.

One study asked groups of participants to give their views on a person describing their experiences of mental illness. In one group, participants were subsequently given a biological and genetic explanation of mental illness, in another, they were given a social and psychological explanation. The group given the biological explanation were much more likely to rate the person as dangerous and unpredictable. Other research has suggested that clinicians with a purely biological perspective are likely to rate patients as more disturbed than other clinicians.

So why do simplified theories – like the ‘low serotonin’ theory of depression, persist – despite overwhelming evidence to the contrary ?

One view is from noted psychiatrist and psychopharmacologist David Healy who has criticised drug companies for promoting simplified biological theories of mental illness that seem to imply the primacy of drug treatments while ignoring social and developmental factors, which are known to be important influences in the development of mental illness.

Focusing specifically on depression and the development of antidepressant medication in his book The Antidepressant Era, he argues that drug companies have spent as much time marketing diseases as treatments, and laments the influence of pharmaceutical companies on scientific understanding.

Healy’s views are not without controversy and need more unpacking than is space for here, although perhaps we can forgive overworked clinicians for seeing the attraction of simple ‘one sentence’ explanations for mental distress, despite the obvious complexity of the issue.

Conclusion
It is clear from the scientific literature that a purely biological theory of mental illness is not sufficient to explain and treat the experience of mental distress. Furthermore, simplified theories, that argue, for example, that depression is ’caused by low serotonin’ are lacking in support and best avoided.

Psychological factors are equally important as biological factors in both the treatment and understanding of mental distress. Denying one or the other will undoubtedly slow scientific progress and lead to further misunderstanding of ourselves and each other.

16 Comments

  1. shannonlove
    Posted May 18, 2005 at 4:54 pm | Permalink

    I think a big part of the problem in talking about depression is that we use the same word “depression” to describe a range of intensity that runs from the let down feeling a person gets because a date canceled to the suicidal ideation of someone with bipolar disorder. Minor depression probably isn’t biological in origin whereas bipolar disorder almost certainly is.
    In my experience, people (even medical professionals) who have only seen or experienced relatively mild depression tend to lean towards the psychological explanation while those who have seen or experienced severe depression or bipolar disorder tend to lean to the biological explanation. They’re both probably right but like the proverbial blind men with the elephant they are looking at different aspects of the same problem.
    I think the success of SSRI’s caused many to assume that the cause of even minor depression must be biological but as noted above anti-SSRI’s don’t cause depression. A better explanation is that SSRI alter cognition, not emotion. They stimulate the advanced cognitive areas of the brain which allows people to more rational examine situation making it more apparent that their depressive feelings are not warranted. (Cognitive therapy can accomplish the same thing but takes longer.) Telling, I think, SSRI’s are not very effective in combating severe depression and don’t work well in those with bipolar disorder.
    I think the problem we have in talking about when talking about the mind and brain is that most do not understand that the two elements are locked in a feedback loop with each other. In analogy with computers, the mind or psychological elements would be the software whereas the brain or physiological elements would be the hardware. Like a computer, hardware failure can cause software failure however, unlike a computer, the software alters the hardware as it runs.
    Two individuals could in theory end up with the same psychological and physiological state even though one started out from psychological pole and the other started out at the physiological pole. Whether any particular case of depression is of psychological or biological origins probably can’t be determined before hand. Each clinical case probably has to be examined in isolation.

  2. Posted September 29, 2005 at 10:55 am | Permalink

    The ‘depression is a physical illness’ claim beloved of so many drugs companies and their partners in crime ‘psychiatrists’ ignores the wisdom of ages and recent discoveries that compare and contrast depression (melancholia) to mourning and loss. The characteristics of the mental suffering endured in a depression are strikingly similar to those of mourning. Indeed Freud suggested that a major loss in ones life that alters an individuals current way of living and world view can induce in that person the mental pain then called melancholia. It is often the case that a recent loss trigers earlier memories of previous losses which can exacerbate the severity of the ‘depression’.
    Viewed this way, it seems rather naive, if not plain stupid, to view depression purely as a physical illness. Depression is all about grieving over some loss or other, be it the loss of a pet, a person, a job, a limb or simply a way of life previously enjoyed. Most of us who practice psychotherapy are all too aware that it is the loss of someone or something in a persons life, or perhaps their lifestyle itself, that precedes and precipitates the array of symptoms and feelings we now call depression.
    julian behrman C.Psychol MSc MA BSc DipExPsych
    Chartered Psychologist and UKCP Psychotherapist

  3. ivan
    Posted October 11, 2006 at 3:15 am | Permalink

    Stating that the prescription of antidepressant is a pharma-industry and “psychiatrists” crime or plot could easily invoke the opposite argument. Namely, that the psychotherapist who claims this also has some financial interests in promoting his or her view on depression as an ailment simply curable by a “chat”-therapy. But, trying to get further from these low-level issues into the realistic understanding of mind and brain, mental and physical, I think that the relation between these is a kind of two-way street and that all the possible explanations of the brain-mind diseases should be taken into account and validated without prejudices. Otherwise we can eventually again get stucked into another round of the nature vs.nurture mudwrestling, which also doesnt do much to solve the real problems.

  4. Pat
    Posted September 12, 2007 at 6:28 pm | Permalink

    Psychiatrists and psychologist need to work together. Combined cognitive/behavioral and medication therapy has often proved to be more beneficial than either alone.

  5. Posted September 5, 2008 at 11:22 pm | Permalink

    Many well-known therapists believe that ;biological and psychological
    factors both play a large and affective Role .
    Here – In this comment – I will try to Deal with the biological one ..
    Feelings of depression are caused by a chemical change that affects
    how the brain functions.
    A normally functioning brain is a giant messaging system that controls
    everything from your heartbeat, to walking, to your emotions. The
    brain is made up of billions of components with called “nerve cells”
    or “neurons” . These nerve cells send and receive messages from the
    rest of all your body, using brain chemicals “neurotransmitters” .
    These chemicals in the human brain are responsible for our emotional
    state. Depression happens when these chemical messages are not
    correctly send or received between brain cells, which affect the
    communication.
    (i. e., A telephone): If your telephone has a weak signal, you can’t
    hear the person on the other end. so it is disabled or unclear
    It has been proposed that even the people who already suffering
    depression, have a way to treat it passed on the biological side, This
    way is the “Medications” .
    The main role of the “Medications” Is to fortify weak signals by
    raising the levels of certain neurotransmitters . which guarantee that
    the brain’s messages are submitted loud and clear.
    …More information and Related Topics at My Blog!

    http://no4depression.blogspot.com/

  6. Posted September 5, 2008 at 11:25 pm | Permalink

    Many well-known therapists believe that ;biological and psychological
    factors both play a large and affective Role .
    Here – In this comment – I will try to Deal with the biological one ..
    Feelings of depression are caused by a chemical change that affects
    how the brain functions.
    A normally functioning brain is a giant messaging system that controls
    everything from your heartbeat, to walking, to your emotions. The
    brain is made up of billions of components with called “nerve cells”
    or “neurons” . These nerve cells send and receive messages from the
    rest of all your body, using brain chemicals “neurotransmitters” .
    These chemicals in the human brain are responsible for our emotional
    state. Depression happens when these chemical messages are not
    correctly send or received between brain cells, which affect the
    communication.
    (i. e., A telephone): If your telephone has a weak signal, you can’t
    hear the person on the other end. so it is disabled or unclear
    It has been proposed that even the people who already suffering
    depression, have a way to treat it passed on the biological side, This
    way is the “Medications” .
    The main role of the “Medications” Is to fortify weak signals by
    raising the levels of certain neurotransmitters . which guarantee that
    the brain’s messages are submitted loud and clear.
    …More information and Related Topics at My Blog!

    http://no4depression.blogspot.com/

  7. Posted September 25, 2009 at 5:41 pm | Permalink

    You have done an excellent information! this is a wonderful article, very well wrote.
    Congratulations for it!
    Juanita R. Mcniel Viagra Online

  8. A Dead Head
    Posted September 27, 2010 at 6:49 am | Permalink

    RE: “Furthermore, drugs which increase serotonin levels in the brain typically do not start having an effect on mood for several weeks, despite affecting serotonin levels immediately”

    I DID immediately (within 36 hours, possibly less) notice a MAJOR difference in my MOOD (EMOTION, NOT necessarily “thinking”, though I did notice that my thoughts were more positive, BECAUSE I FELT much better, mostly my thoughts were, “Wow, I feel much better! I FEEL like I am enjoying life.”) upon beginning a moderate SRRI regimen. So, the idea that SRRIs affect cognition and not emotion are patently false, in my experience. It is the EMOTION that leads to my more positive thinking, simply because I feel better, more joy in simply being alive.
    Further, it takes about 12 hours or so AFTER I take my SSRI before I notice that my mood is markedly improved, there is a peak to it that is directly correlated to when I took my dose. So, increased seretonin levels DO EQUATE with an increased feeling of well-being, and do so predictably in a matter of hours after I take them. My cognition has not varied all that much yet, other than that I notice when I feel better and am more hopeful at those times, which is directly related to when the SRRI’s effect is at its peak. Cognition is not affecting my mood, it is the seretonin that is affecting my mood. I am generally very in tune with my feelings and am quite sure of my statements. I’ve only been on SRRI for less than a week!

    • Debbie
      Posted May 31, 2011 at 10:01 am | Permalink

      I think we are all unique. For me I have the same experience, being that once I start feeling physicalluy better, which happens when i take ssri’s, my thoughts change and becomore more logical/rational/positive, because i feel better. I am going for counselling as well, just to make sure that there aren’t any psycological issues that is causing this, but I don’t believe that this is the main cause anymore, because i have met people who have been through trauma and yet they do not get depression. and i really wish they would change that word, cause i don’t even really get depressed anymore, i just get extremely tired and for some reason the ssri’s sort that and a number of other little ailments out for me.

  9. Julie
    Posted October 12, 2010 at 8:28 am | Permalink

    Yeah! “Big-pharmaceutical-companies-are-making-it-up” conspirationist FTW!

    Dear delusional individual: Do big pharma companies make loads of cash making these medications that treats these very real biological illnesses (be they neurological like depression or otherwise)? Yes. Does that mean that they are “making up illnesses”. OF course not.

    Yours is like saying Subway restaurants makes loads of money selling fast food therefore that chain must be responsible for people eating food.

    I tend to doubt the sanity of someone who believe in some big conspiracy theory that would involve nearly all of the mainstream scientific research, the whole field of neurology, all psychiatrists etc etc..Seriously, I don’t believe so.

    Incidentally, you make a lot of pseudo-philo-intello-wanking arguments in your diatribe, yet you don’t cite a single scientific source.

    And now I wonder if your conspirationist delusional thoughts couldn’t be caused by a severe delusional mental illness:

    http://www.psychologytoday.com/articles/200501/conspiracy-theories-explained

    Please get the psychiatric help you need. Good luck.

  10. ShannonL
    Posted April 11, 2011 at 3:55 pm | Permalink

    Hello Mr. Bell. I was wondering If I would be able to email. I am doing a research paper for school about depression and I was reading your article and you have a lot of information about depression and I would like to interview you.

  11. Katya
    Posted November 11, 2011 at 5:18 am | Permalink

    Julie,

    “Incidentally, you make a lot of pseudo-philo-intello-wanking arguments in your diatribe, yet you don’t cite a single scientific source.”

    The serotonin theory has been discarded by almost all credible scientists. This is not a conspiracy theory- it’s the result of rational thinking. The pharmaceutical companies aren’t necessarily making anything up- they’re misleading and simplifying. In other words, they’re profiting from other peoples ignorance (read: your ignorance). In fact, their advertisements have come under heavy scrutiny by consumer right groups. Why? Their outlandish claims are unsupported by science.

    Studies done by groups with no attachment to pharmaceuticals are considered ethical and objective. Studies untainted by profit show that bio-bio-bio theory of mental illness is false. It is also damaging to a notable percentage of people.

    Even considering the history of the SSRI, it is hilarious you think it has any foundation in ethical science or medicine. Even George Ashcroft, the man who hypothesized that depression was caused by deficits of serotonin, abandoned the theory. Why can’t you?

    “… it turns out that there is currently no scientific consensus that depression is linked to serotonin deficiency or that SSRIs (Selective Serotonin Reuptake Inhibitors) restore the brain’s normal ‘balance’ of this neurotransmitter. The idea that depression is due to deficits of serotonin was first proposed by George Ashcroft in the 1950s, when he thought he detected low levels in the brains of suicide victims and in the spinal fluid of depressed patients. Later studies, however, performed with more sensitive equipment and measures, showed no lower levels of serotonin in these populations. By 1970 Ashcroft had publicly given up on the serotonin-depression connections. To date, no lower levels of serotonin or ‘imbalance’ of the neurotransmitter have been demonstrated in depressed patients. The American Psychiatric Press Textbook of Clinical Psychiatry states simply, ‘Additional experience has not confirmed the monamine (of which serotonin is a subgroup) depletion hypothesis.’” – from Crazy Like Us by Ethan Watters

  12. Nick A.
    Posted January 21, 2012 at 1:59 am | Permalink

    I definitely believe that depression is a multi faceted illness and can only be cured by the individual with depression`s own personal recollection of their own life. Whether that leads to the person deciding to make lifestyle changes, or whether they need to take some medication and do some therapy to get themselves out of a funk, or another remediation, it should be a healing process that involves the person with depression`s own thoughts. I feel as if people with depression go to a psychiatrist, get told something will work, this is your problem, and this is the ONLY solution and that is it. there is little to no personalized diagnosis other than the amounts of mgs of the pills. I myself who has had depression since i was 13, and am now 19, believe that medication could help me, but i know for a fact that even if i took the best drugs in the world that fixed whatever problem I have in my head, I will never be happy until I fix the problems in my life that are responsible for my depression, and more importantly began my depression.

    I have few friends and have always had a turbulent home and social life. I was abused when I was younger for several years and I have little positive stimulation in my life due to my guarded nature and constant state of fear do to my habits. I have dreams of being someone who I currently am not on the track to being and I have incredibly high expectations and I am not doing enough with myself. I am not completely opposed to drugs but I believe that drugs are only a medium to get you to a state of mind that cures you yourself. Whether you need drugs to get to that state or not, the drugs should always only be looked at as a medium and not a cure, other than special cases. But even said if some medication can 100% heal people with certain neuron-transmitting issues, why is there no specific way of diagnosing people who have that specific problem, fixing it, and saying that people with certain roots of depression can be cured? To me it all screams bullshit. It is just like cancer, billions of dollars donated and given to cancer research, yet years later, no cure, no advancements, same way of treating it nothing accomplished. I have a link of a Suzanne Summer’s interview, where 6 doctors diagnose her with cancer when she actually never had it in the first place and she probably would have died if she believed them.

    And to Julie, your comment is kind of laughable. It is actually a law that says only drugs can cure any sickness, and if you state that anything other than a pharmacy drug cures something you can go to jail. what kind of honest company says that only drugs can cure a sickness and if you say anything else can work other than what they sell, than you can go to jail even if it completely works and there are facts that back it up? That would be a fraudulent one. Also it’s a fact that things other that drugs can cure things since new cures are being discovered all the time due to new technological advances. So if you figure out a cure before the FDA then you’re a criminal because you beat them to it? what a bunch of bull, that itself shows that obviously the FDA is a shady business.

    To Katya, thank you for dumbing things down for Julie since obviously what everyone was stating was how the FDA is misleading and inflating everyone’s perspective to make money. They may not be lying but they of course use advertising to bloat the effects of medication for a disease that is not even curable. If it is not curable then don’t make stupid advertisements about how your products work when it is a fact that nothing completely works.

  13. The view from here
    Posted March 12, 2012 at 6:24 pm | Permalink

    If it will help here is one account from someone personally experiencing it. You can decide if it is physical or mental. Not sure of all the causes but for me, I experience problems with executive functioning. When I try to get things done, I get overwhelmed. I then get anxious and feel bad because I cannot get things done and feel there are expectations both from others and myself to get things done.

    This morning I woke up feeling I could function and started doing things. But as I moved through doing things, I started to see more things that needed to get done and could not halt that cascade.

    I got anxious. Then about four hours into my morning I felt this overwhelming feeling of — I cannot explain it but it was almost palpable, it was a feeling of anguish, and some sort of emotional pain that I wanted to escape.

    It just took over me before I even started to think about it. The anguish and the low came rushing in out of NO WHERE.

    Then came the thought of suicide. It happened by itself (no ruminating) and just took over.

    However, I sat there and was aware that the feeling came on strong and fast (30 minutes) and talked myself into believing that it will pass so just hold on.

    But it was an intense drop and I definitely felt something. But it was not a headache, joint pain, stomach ache… nothing like that. I don’t even get those pains like is described in the so-called symptoms of depression. It was a pain I wanted to escape very badly though. It was in my head/brain/mind, whatever term works for you.

    So I looked up the idea of depression being FELT as physical.

    That is what I felt. But as for the causes of it, who knows? It could be a practiced (well traveled) neurological pathway as a result of how I have tried and tried and failed at life for so long. Please no violins, this is ONLY an observation not a sympathy call. I am not into that.

    Oddly enough though, the feedback I get from others is that I am always so “level-headed” and they come to me for “advice” about their problems. So while my perspective seems to be widely accepted and sought by persons who are able to function at a high level, I feel that I cannot function. Others seem to believe that but I am not functioning to the level I have proven I can and different times in my life.

    I cannot put one foot in front of the other and think at the same time. I think I may have executive function and working memory issues and maybe ADHD. But I wonder if what is labeled ADHD is really executive dysfunction?

    Anyway that MAY be the cause of the depression which then caused a physical outlay of screwed up neurological circuitry.

    Meaning, I think I have a processing problem, it led to a dysfunctional life in spite of my many efforts (my college professors always told me the one they can say is that I have “perseverance.” That is funny. I have nothing else but I have “perseverance.” So outside observers support what I say about trying very hard. This is a realistic observation in other words – it’s an objective not subjective observation ). This then led to a lot of failures.

    Due to my life experiences and aside from whether depression is physical or not, I keep running to both sides of the court about this saying, ‘what does not kill you makes you stronger.’ That has got to be the biggest bunch of self-therapy. self rationalizing bull—- or cognitive dissonance that could ever be.

    I hope someone figures it out because I really want to put my college degrees to use and pay taxes (er, do something I like and is worthwhile to society).

    • me
      Posted February 19, 2014 at 4:47 am | Permalink

      Unbelievable!! After years of trying to make sense of what is happening with me, and scouring through sites of this nature, i have finally come across something so similar to my own situation. What you (the view from here) described re. failure of the executive function process and how it has affected your life then and (I’m guessing..) now is almost exactly what has been happening with me for most of my life.
      I’m not sure why I feel compelled to reply since i have nothing to contribute to the discussion. It does not help me, i don’t think. I guess it’s just an acknowledgement.

  14. The view from here
    Posted February 19, 2014 at 6:18 pm | Permalink

    Hi Me,

    Reading what I wrote I am surprised I was able to write that since today I cannot even put a sentence together – I am brain dead today, not depressed but functioning as if I lost some amount of intelligence. It might come back if I take my brain out of the protective park mode it’s in.

    However, I want to address several things about your comment

    One: Glad what I wrote had some meaning, created some clarity or provided a frame-of-reference from which you can relate to/use/change/contemplate etc…

    Two: Your quote, “I’m not sure why I feel compelled to reply since i have nothing to contribute to the discussion.”

    Hmm, contribute? Your acknowledgement is a contribution and in various ways. But one important way is that it means that some aspect of what I experience occurred with someone else and voila, we have replicable, observable data also known as what constitutes fact in the scientific world.


Post a Comment

Required fields are marked *
*
*

Follow

Get every new post delivered to your Inbox.

Join 24,087 other followers