Depression is a Whole-Body Disorder. Why Don’t We Treat It Like One?
Today marks the start of Mental Health Awareness Week in the UK. In previous years the campaign has explored the experiences of living with mental illness, social stigma and support resources. This year the focus has changed from living with illness to asking why so few of us are thriving psychologically. Why are so many of us in ‘survival mode’? It’s an approach that invites us to look at the wider factors influencing mental health on a sub-clinical level. When most of the people who experience depressive or anxious symptoms will not or cannot access treatment it is important to understand other viable and effective avenues for intervention.
This broader theme of what it means to ‘thrive’ reflects a growing appreciation that disorders such as depression are not simply ‘brain-based’ but are biological and psychological responses to social, environmental and lifestyle factors. Just a few days ago a review of 20 years of depression research concluded:
“…one thing is for sure: depression, and mental health problems in general, can no longer be seen only as disorders of the mind, or indeed only as disorders of the brain. The strong impact of the immune system on emotions and behaviour demonstrates that mental health is the health of the whole body.”
Two years ago the Lancet Psychiatry released a statement editorial highlighting that ‘nutrition is as important to psychiatry as it is to cardiology’ and advocated that nutritional status and dietary intervention should be considered when assessing a person’s mental health condition. The recent publication of the ‘SMILES’ Trial was the first study to elucidate diet as a causal factor in depression. Mood improvement in this study was not a factor of weight loss and while this particular study did not assess these parameters it is likely that the improvement was due to a reduction in systemic inflammation, as has been highlighted by a number of observational and RCT trials.
Inflammation is the immune system’s response to illness or injury, which, amongst other things, involves the release of small molecules called cytokines by immune cells. Typically, the inflammatory response is brief and begins to recede when the tissues start to heal. However, a number of stressful external factors also induce inflammation and the secretion of pro-inflammatory cytokines including: early life adversity, traumatic events, chronic work stress, poor diet, obesity and a sedentary lifestyle. When stress is sustained so is inflammation and this state of low-level chronic inflammation is implicated in a range of diseases including heart disease, Type 2 diabetes, Alzheimer’s Disease, and depression. Blood levels of inflammatory cytokines correlate with the severity of depression that patients report. In one trial non-depressed participants were injected with a substance called endotoxin, a toxin found in the cell walls of bacteria that the immune system recognises as harmful. The participants who were injected with endotoxin not only saw an increase in their levels of cytokines but reported significantly increased anxiety, depressed mood and loss of pleasure (a symptom of depression). The participants who received the placebo did not report these mood effects.
As well as improving diet, exercise has been shown to be effective in reducing levels of inflammation, improving mood and increasing the levels of a substance called BDNF. BDNF is a growth factor that promotes the growth of new brain cells, as well as protecting the ones we already have. Low levels of BDNF have long been associated with depression and other mental illness. Exercise mimics the action of antidepressants by raising levels of BDNF and improving the availability of the neurotransmitter serotonin, which is associated with good mood. Exercise has the additional benefit of improving heart health and general brain structure and function, and improving sleep (sleep disorders are a common factor in depression). Taking a similar position to the Lancet Psychiatry report, a recent editorial in the journal General Hospital Psychiatry makes the case that the evidence for the beneficial effects of exercise on mental health is so compelling that it is time to start thinking about how to apply it as treatment.
Other lifestyle factors have also been shown to be effective in improving mental health including meditation, learning, fasting and even sauna use. Combined, these factors present us with the best cost-effective opportunity to reduce and prevent the development of depression and associated disorders. Sadly, few people will have access to this valuable information and support. Conducting a thorough assessment into what might be causing one person’s depression takes more time than the ten minutes GP’s are allotted per person. Psychological therapies are effective but can be difficult to access. Thus, antidepressant medication remains the most cost-effective treatment available in Primary Care. The problem is that rates of treatment-resistance (patients not responding to antidepressants) are increasing. The lifestyle factors outlined above provide opportunities to both improve the efficacy of standard treatments and as standalone options for those with mild-moderate symptoms.
Hopefully, this year’s campaign will make the case for considering lifestyle interventions in the treatment of depression. For my part, my clinical practice starts with a comprehensive assessment of both psychological and lifestyle factors including: work satisfaction; relationships; childhood illnesses, exercise; diet and nutrition, and sleep habits so that the client and I can come to as clear an idea as possible of what might be causing their distress and illuminate a number of areas for intervention to give us the best chance for a positive outcome.
To increase the availability of this valuable information I am launching a series on online seminars on a range of topics including Stress Management, Sleep, Nutrition and Obesity. It’s times for us to move away from a model of symptom management to one of illness prevention, and all change starts with awareness.
Dantzer, R., O'Connor, J. C., Freund, G. G, Johnson, R. W, Kelley, K. W. (2008). From inflammation to sickness and depression: when the immune system subjugates the brain. Nature Reviews Neuroscience, 9(1), 46–56. doi:10.1038/nrn2297
Ekkekakais, P. & Murri, M. B. (2017). Exercise as antidepressant treatment: Time for the transition from trials to clinic? General Hospital Psychiatry. Doi10.1016/j.genhosppsych.2017.04.008
Miller, A. H., & Timmie, W. P. (2009). Mechanisms of Cytokine-Induced Behavioral Changes: Psychoneuroimmunology at the Translational Interface Norman Cousins Lecture. Brain, Behavior, and Immunity, 23(2), 149–158. http://doi.org/10.1016/j.bbi.2008.08.006
Pariante, C. M. (2017). Why are depressed patients inflamed? A reflection on 20 years of research on depression, glucocorticoid resistance and inflammation. European Neuropsychopharmacology. In press.
Sarris, J. et al. (2015). Nutritional medicine as mainstream in psychiatry. The Lancet Psychiatry, 2(3), 271-274.