A comprehensive analysis of existing research into the 'chemical imbalance/serotonin' theory of depression, challenges decades old thinking and produces shocking findings that alter the understanding and treatment for those that present with clinical depression.
“Roughly 80% of the general public believe that depression is caused by a ‘chemical imbalance’. Many general practitioners also subscribe to this view and popular websites commonly cite the theory." Moncrief, Cooper, Stockman, Amendola, Hengartner, & Horowitz, 2022, Journal of Molecular Psychiatry
In a 2022 paper published in the Journal of Molecular Psychiatry the authors challenged what has generally been an accepted theory of depression for decades; the chemical imbalance theory. This theory was first introduced in the 1960’s, rooted in the 1990’s and has remained widely held since that time. The researchers conducted a review to determine if in fact the widely popular and accepted theory, that depression is caused by a chemical imbalance, (low serotonin levels) was empirically supported. The results were shocking to many and will better inform understanding and alter treatment practices moving forward for those suffering from clinical depression.
"Our comprehensive review of the major strands of research on serotonin shows there is no convincing evidence that depression is associated with, or caused by, lower serotonin concentrations or activity. Most studies found no evidence of reduced serotonin activity in people with depression compared to people without, and methods to reduce serotonin availability using tryptophan depletion do not consistently lower mood in volunteers." (Moncrief, Cooper, Stockman, Amendola, Hengartner, & Horowitz, 2022, Journal of Molecular Psychiatry)
Dr Nassir Ghaemi MD/MPH, is a psychiatrist/researcher specializing in depression and bipolar illness. He is Professor of Psychiatry at Tufts Medical Center in Boston and Clinical Lecturer at Harvard Medical School. As he states, it hasn’t quite been “debunked” but rather, it was never proven or empirically supported to begin with. This may be shocking to many and was certainly not reflected in mainstream thinking prior to the 2022 research review. “Roughly 80% of the general public believe that depression is caused by a ‘chemical imbalance’. Many general practitioners also subscribe to this view and popular websites commonly cite the theory." Moncrief, Cooper, Stockman, Amendola, Hengartner, & Horowitz, 2022, Journal of Molecular Psychiatry Ghaemi described the outdated theory as an “overly simplified and false hypothesis”. Tangibly, he compares using SRI’s (serotonin reuptake inhibitors) to treat depression, to the use of aspirin to treat a fever. While it can be helpful and can alleviate symptoms, it doesn’t address the underlying cause. In the case of fever, it’s typically an infection of some sort. With depression, it can be much harder to pinpoint the cause. There is no biological biomarker for depression. Depression or MDD-major depressive disorder as defined by the DSM, (Diagnostic & Statistical Manual for the treatment of Mental Disorders) encompasses many psycho/social markers. He distinguishes MDD from other biologically based illnesses like manic depression and schizophrenia.
“Depression is not a disease; it is a set of symptoms, like fever, chills, and night sweats. I would be a bad doctor if I just gave you anti-fever pills and anti-chill pills and anti-night sweat pills, instead of treating the infection that caused all those symptoms. Similarly, antidepressants like SRIs improve the symptoms of depression somewhat, but don’t get at the cause. Just like aspirin and Tylenol can improve the symptoms of fever somewhat, but don’t get at the cause. We might use antidepressants short-term for symptom benefit, but we should also try to find the disease that is causing your depression.” SRIs are only symptomatic drugs; they reduce symptoms of depression somewhat, just as aspirin reduces symptoms of fever.” Dr. Nassir Ghaemi, Psychology Today,
As Dr. Ghaemi suggests, depression is not a disease and can be best understood as a set of symptoms. Effective treatment plans for depression need to consider more than a pharmacological approach. It is not to say that medication cannot be helpful or a part of the treatment plan but it’s clear that it cannot be the only part.
Given that the serotonin theory is inaccurate at best, this begs the question: How do we approach the exploration and treatment of depression? The Bio-psycho-social Model of Health, first conceptualized by George Engel in 1977, offers a way. As a Social Worker and a Humanistic Psychotherapist, I have always held the belief that to treat an individual you must understand their life story and circumstances, past and present. The bio/psycho/social model of health I lean on, offers a comprehensive framework for understanding the complexity of our human experience and a foundation for exploring the factors at play when someone is experiencing depression.
Essentially, this means that we cannot understand someone or what they are experiencing, without understanding their environment (present and past), specifically, the biological, social and psychological aspects of their existence. The bio-psycho-social model of health offers a framework for that understanding. One aspect I feel the model is lacking is the spiritual realm of our nature. Nonetheless, it does facilitate a broader perspective and template for exploration.
THE BIO-PSYCHO/SOCIAL MODEL OF HEALTH
Overly simplistic solutions to complex problems, lead to ineffective outcomes.~Theobald, 2024
It's time to move beyond simplistic explanations and symptom management. Leading with curiosity allows us to investigate underlying factors and life circumstances that may be contributing to a persons' depression. We have to abandon outdated theories and consider what is referred to in my field as, “PERSON IN ENVIRONMENT.” We must consider the social/psychological/biological factors present, as well as the complex interplay between them. We are multi-faceted beings in dynamic interaction with our environment. We shape and are shaped by our environment. Our treatment approaches need to be equally dynamic. Overly simplistic solutions to complex problems, lead to ineffective outcomes.
My approach to treating depression is similar in many ways to what doctors do when a patient presents with a fever, first I get curious, and I begin to look for underlying causation. Biological, social and psychological factors are all important to explore. A great example of this is someone that experiences seasonal affective disorder or 'SAD'. If someone generally feels well most of the year but experiences seasonal dips in mood, then very likely this may be due to biological factors-vitamin D levels decreasing as well as perhaps decreased exercise/movement. These would be biological factors. Still, social factors such as lower social contact and isolation may be another piece of the equation. Imagine a person that used to have a friend they walked with daily who passed away. This would be a change socially for them. This might influence their walking routine. It’s also possible that psychological factors might ensue. If they were grieving this friend and experiencing decreased motivation to walk, this would be the psychological impact of that social change. Time of year trauma triggers (known or unknown) could also be causing or exacerbating symptoms. It’s also likely that the complex interplay of all these factors-outlined in the model are pertinent and contributing to mood dysregulation. Each of these factors need to be considered and addressed in the treatment plan. Dr. Ghaemi suggests and I would concur that,
“The use of SRIs should be based solely on the efficacy data shown for those agents in randomized clinical trials. Those data are indeed weak, and thus, I hold the view that SRIs should be used much less than they are, and for shorter durations, but this view has nothing to do with the already known false concepts of a serotonin theory of depression.” Dr. Nassir Ghaemi, Psychology Today,
Responsible mental health care and competent treatment, requires a holistic approach and a comprehensive treatment plan, tailored to meet the specific needs of the individual. We need to rely on the most accurate and up to date research and tailor our treatments in response. We have to move beyond symptom management and to do so, we have to treat people holistically. We have to look at the ‘person in environment’ which includes biological/social/psychological elements and I believe spiritual as well, that may be at play.
The view that depression is not a disease but more accurately understood a set of symptoms that need to be explored, leads to a more holistic, comprehensive and I believe respectful orientation toward the person suffering. There is great power in naming our experience and being able to make sense of it. A strictly chemical view puts the blame on the individual and their neurochemistry and may add further to their sense of sadness, helplessness or hopelessness. What's clear from the research is that depression cannot be simply understood as a chemical imbalance. It is far more nuanced and complex. A diagnosis is a recognition of a set of symptoms you are experiencing that need further exploration. If you are feeling depressed, get curious, look at your environment (past and present). What factors from the model can you identify and influence or take action on? Do what you can. If you are stuck connect with a friend, call your doctor or a mental health professional. Don’t suffer in silence. Reach out.
Healing is possible. Hope is essential. Help is available.
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