Is depression centered in the brain? The “broken brain” or “chemical imbalance” model is too simplistic. As you can already assess, there are multi-layered processes in both body and mind that factor in the development of depressive symptoms.
Depression is a prevalent mental health condition worldwide and is the leading cause of disability in adults under the age of 45. The mechanisms underlying depression remain poorly understood even though stress and its correlates contribute to multiple aspects of the phenomenology of depression. Based on an emerging picture of how stress and mood are regulated within the nervous system, we can understand depression as a complex response to extreme stress. Exposure to chronic stress, whether physical or psychological in nature, has cumulative effects on the body and mind.
The demands of “modern” life – requiring us to be constantly on the go, propelled by caffeine and perfectionism—seem to elicit a chronic over-activation of the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal axis (HPAA). As we saw in the anxiety article, a chronically activated sympathetic response will eventually lead to a complete shutdown of the body mediated by the dorsal vagal parasympathetic branch – leading to symptoms of major depressive disorder (MDD):
a) depressed mood or loss of pleasure (anhedonia)
b) feelings of guilt or worthlessness because of negative interpretations of the immobility response which comes in conflict with societal demands.
c) cognitive slowing, further eroding self-confidence and self-worth.
d) changes in sleep, which increase inflammatory influences in the brain.
e) changes in appetite, which may lead to eating inflammatory foods and interfering in the modulation of the nervous system.
f) potential suicidal ideations if the weight of the self-judgment becomes unbearable and hopelessness ensues.
Ongoing arousal of the SNS/HPAA has both physical and psychological consequences. Psychosocial stress can activate peripheral and neural inflammation, which is exaggerated in individuals with MDD. Individuals experiencing depression have higher circulating levels of proinflammatory cytokines. High levels of these cytokines are associated with fatigue, cognitive dysfunction, and altered sleep. Symptoms of depression seem to emerge as cytokines activate neural pathways that influence the basal ganglia, an area of the brain involved in motivation and motor activities. This could explain the low motivation and motor movement inhibition associated with depression.
Other brain regions involved in the control of mood, including components of the PFC and limbic system are also affected by these inflammatory pathways, which is leading researchers to hypothesize that the release of stress hormones (corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol) are a major factor in depression. Psychiatrists are experimenting with anti-inflammatory medications in patients who do not respond to common antidepressants – anecdotally with great success.
Is depression centered in the brain? The “broken brain” or “chemical imbalance” model is too simplistic. As you can already assess, there are multi-layered processes in both body and mind that factor in the development of depressive symptoms. They involve multiple organ systems and a variety of hormones and neurotransmitters. However, emerging evidence implicates dysfunction in a circuit including cortical areas and limbic areas that regulates mood, learning, and memory processes. Research suggests that symptoms of depression may result from dysfunctional asymmetry of activity between the left frontal lobe (causing decreased positive affect) and the right frontal lobe (causing emotional lability, difficulty with emotional information processing, and decreased arousal). This is particularly true in individuals who experienced childhood abuse and developmental trauma that impaired the proper development of these emotion-modulation areas. This development occurs after birth in the dyadic interactions between infant and caregivers.
A key individual factor in the effect of stress may be the degree to which an individual perceives the stress to be significant and to what degree the individual thinks she/he has control over the situation. Anything that helps an individual experience a sense of mastery over their internal experience and external world will help reduce depression. Paraphrasing Indu Arora, yoga is not a feel-good practice. Yoga is a practice that requires self-study, svadyaya, and consistent practice, abhyasa while cultivating qualities of non-judgment, self-compassion, and lovingkindness. The bad news is that quick fixes (demanded by a “rapid results” culture) do not exist. The good news is that healing is possible through effort mediated by santosha, or contentment for patient improvement.
We begin by reducing the stress response that ultimately leads to depression. So, in addition to the outline on the eight (8) limbs of yoga outlined in the anxiety section of this 3-part blog post series, the following considerations should be taken for people experiencing depression:
1. Goal: Establish the observer, a capacity to witness and deconstruct phenomenological experience rather than identify with it. Slowly increase sympathetic arousal through movement and deeper inhales. Expand the capacity to tolerate the potential “distress” of higher arousal states by shifting frequently between movement and restful phases – which will invite the natural rhythm of the nervous system.
2. Attitude: Support motivation to practice by highlighting mastery of the foundational aspects of yoga. Facilitate continuity of effort by offering simpler, step-by-step practices that provide an experience of gradual change.
3. Strategies: Begin slowly and gradually increase activity to break up inertia. Use mainly brahmana practices that emphasize dynamic movement coordinated with breath. Titrate entry into more energizing poses by starting with supine poses and move slowly to standing or balancing poses.
4. Asana: Categories that are helpful: extensions, laterals, gentle backbends, and twists followed by a long savasana to help increase cardiovascular capacity, “digest” the sympathetic arousal that emerges, and integrate the balance of sympathetic/parasympathetic arousal. Savasana with rhythmic breathing has been shown in research to relieve depression.
5. Bandhas/Chakras: Uddyana bandha is particularly important to awaken the dorsal vagus nerve (which is subdiaphragmatic and enervates digestive organs), activate the 3rd chakra (willpower, determination, self-awareness), build the energetic “fire” (agni) that supports transformation and the digestion and assimilation of food and psychological states.
6. Pranayama: Focus on ujjai which is warming and centering; increase length of inhales with short holds after inhale to build energy and stamina; create heat with bhastrika.
7. Meditation: Concentrate awareness at the navel center with the seed mantra for that region, RAM, to build courage and positive self-identity. Learn the Maha Mrityunjaya Mantra to dissolve fear and darkness.
Current research supports the idea that various yoga interventions can help participants improve self-reported perceptions of stress and well-being. Little research, however, exists on physiological or neurological mechanisms that could mediate the positive effects of yoga on mood and symptoms of psychological depression. Below is a summary of some potential explanations for yoga’s benefits:
• Yoga may influence the inflammatory processes involved in depression by influence on the vagus, the 10th cranial nerve. Efferent (brain-to-body) vagal nerve fibers, via the neurotransmitter acetylcholine, exert anti-inflammatory actions. Thus, because inflammation is implicated as contributing to depressive symptoms, activation of the vagal anti-inflammatory pathway could be an important mechanism by which yoga practice could decrease symptoms of depression.
• The yoga components of slow breathing, relaxation practices, mindfulness of sensations in the body, and physical postures may influence drive on brain pathways to the limbic and cortical areas involved in mood regulation, influencing parasympathetic outflow.
• Rhythmic breathing practices have been shown to affect heart-rate-variability (HRV) and decrease blood pressure. In addition, slow breathing patterns that stimulate the vagus, have been shown to increase levels of prolactin, dopamine, norepinephrine, and serotonin, which are often depleted in depression.
• There have been few studies investigating the effects of yoga on brain chemistry; however, practicing the physical postures of yoga has been shown to increase levels of gamma-aminobutyric acid (GABA), a neurotransmitter in the brain that can have anti-depressant and anxiolytic effects.
• The repetitive practice of yoga, over enough weeks, may provide a sense of accomplishment, positively reinforcing healthy coping and self-mastery, as well as increasing positive self-regard and identity.
• Another way yoga may help is the focus on bringing attention to present-moment thoughts, feelings, and bodily sensations in a non-judgmental way, helping to decrease self-criticism and increasing the experience of thoughts, feelings, and sensations as transient and not permanent events.
• Researchers have also hypothesized that yoga may have a positive impact on related autonomic functioning and in reducing hypothalamic-pituitary-adrenal (HPA) axis activation. Change in these pathways interrupts the underlying stress physiology and decreases inflammation.
• Exercise, as well as meditation, also influences the hypothalamic-pituitary-adrenal responsiveness and leads to adaptions in endocrine secretion of substances such as cortisol and adrenocorticotropic hormones.
This is part 3 of a 3-part series. Subsequent blogs will deconstruct anxiety and depression as well as outline how yoga has been proven by research to help with these conditions. Inge Sengelmann is a licensed clinical social worker and certified ParaYoga teacher who specializes in disorders of extreme stress and is committed to anti-oppression practices and decolonizing mental health.
Inge Sengelmann, LCSW, SEP, RYT is a licensed psychotherapist and certified ParaYoga teacher who promotes a practice of embodied psychology and spirituality. Visit her website at www.embodyyourlife.org.
Photo by Anthony Tran on Unsplash
Photo by Lina Trochez on Unsplash.
