DESIGNED FOR DEPRESSION
Have you ever stopped to wonder if depression has benefits? I know, it sounds a little outlandish to even suggest such an idea. But it’s an excellent question to ask and an even better one to answer. This conversation, however, is best couched within the topic of stress in general. So let’s go there next.
Most of us can recognize the symptoms of stress. We feel it inside and out. We become irritable, our heart races, our face may feel hot, we get a familiar headache or upset stomach, our mind is incessantly chattering, there’s a sense of impending doom, and we’re annoyed by the smallest things. For some people, stress has little outward effect. For these individuals, what they feel at the surface is internalized and sometimes expressed as disease. In fact, many of these people don’t believe they experience stress—but they do; they just don’t consciously recognize it until it builds up to a certain point and seeps out in other ways.
The term stress as it is used today was coined by one of the founding fathers of stress research, Hans Selye, who in 1936 defined it as “the non-specific response of the body to any demand for change.”27 Selye proposed that when subjected to persistent stress, both humans and animals could develop certain life-threatening afflictions such as heart attack or stroke that previously were thought to be caused by specific pathogens only. This is a crucial point, because it demonstrates the impact that everyday life and experiences have not only on our emotional well-being but also on our physical health.
The word stress as it relates to emotions became part of our vocabulary in the 1950s. Its use became common with the onset of the Cold War, which was an era when fear ruled. We were frightened of atomic war, so we built bomb shelters. As a society, we could not say we were afraid; instead, we used the word stress. Today we continue to use the word to describe anything that disrupts us emotionally—we’re stressed, stressed out, under stress, and so on. Stress can also be described as the thoughts, feelings, behaviors, and physiological changes that happen when we respond to demands and perceptions. And if those demands placed on us overwhelm our perceived ability to cope, we experience “stress.” In our frenzied minds, we begin to pant silently like an animal and look for an escape.
Since Selye, researchers have broken stress down into several subcategories. Stress physiology has come a long way in the last fifty years in particular, and so have the stressors. A key concept to enter the medical vernacular more recently is what is known as allostatic load. Your allostatic load refers to environmental challenges—the “wear and tear” on the body—that cause it to begin efforts to maintain stability (allostasis, also known as homeostasis). It also represents the physiological consequences of adapting to chronic stress that entails repeated activation of the body’s stress response machinery involving many systems—immune, endocrine, and neuronal. Researchers Bruce McEwen and Eliot Stellar coined this term in 1993 as a more precise alternative to the term stress.28 The key players of the stress response, cortisol and epinephrine (adrenaline), have both protective and adverse effects on the body depending on when and how much they are used. On one hand, these hormones are essential for the body’s ability to adapt and maintain balance (homeostasis), but if they are flowing for a prolonged period or needed relatively frequently, they can accelerate disease processes. The allostatic load, as it’s called, becomes more harmful than helpful. This load can be measured in physiological systems as chemical imbalances in the activities of the nervous, hormonal, and immune systems. It can also be measured by disturbances in the body’s day-night cycle (what’s called the circadian rhythm, another concept we’ll explore later), and in some cases, changes to the brain’s physical structure.
Stress is actually a good thing, at least from an evolutionary and survivalist perspective. It serves an important function: to protect us from real danger by equipping us with a better means to escape a life-threatening situation or face it head on. But our physical reaction doesn’t change according to the type or magnitude of a perceived threat. Whether it’s a truly perilous stressor, or just the to-do list and an argument with a colleague, the body’s stress response is the same. Let me give you a quick lesson on what goes on when your body senses stress so we can come full circle back to, dare I say, the secret value of depression.
First, the brain sends a message to the adrenal glands that results in the release of adrenaline, also called epinephrine. This triggers your heart rate to increase as blood is directed to your muscles in the event you need to flee. When the threat is gone, your body normalizes again. But if the threat doesn’t go away and your stress response intensifies, then a series of events take place along what’s called the HPA axis, short for hypothalamic-pituitary-adrenal axis, and which involves multiple stress hormones. The hypothalamus is a small but key governing region of the brain that has a vital role in controlling many bodily functions, including the release of hormones from the pituitary gland housed inside. It’s often referred to as the seat of our emotions because it commands much of our emotional processing. The moment you feel nervous, anxious, extremely overwhelmed, or simply worried that you can’t deal with life, the hypothalamus releases a corticotropin-releasing hormone (CRH), a substance that starts a cascade of reactions, ending with cortisol flowing into your bloodstream. While this process has been well defined for a long time, newer research reveals that perceptions of stress trigger inflammatory signaling from the body to travel to the brain, priming it for hyper-response.29
You’re probably already familiar with cortisol, the body’s main stress hormone that aids in that famous fight-or-flight response. It also controls how your body processes carbohydrates, fats, and proteins. Because it’s the hormone responsible for protecting you during times of stress, its actions increase your appetite, promote more fat storage, and break down complex molecules and tissues that can be used for quick forms of energy, including muscle. For this reason, continual exposure to excess cortisol over time can lead to increased abdominal fat, bone loss, a suppressed immune system, fatigue, and a heightened risk for insulin resistance, diabetes, heart disease, and full-blown depression. Cortisol does, however, serve a positive role. It directs and buffers the immune system and primes the body for attack. This would all be great if the attack were short-lived and easily resolved. The attack of our modern-day lifestyles is unrelenting.
The scientific study of the impact of stress on the body from the inside out, and even the outside in, has made tremendous advances in the fifteen years starting in 1998 when Harvard University researchers conducted a joint study with several Boston-area hospitals designed to examine the interactions between the mind and the body, specifically the skin. They called their discovery the NICE (neuro-immuno-cutaneous-endocrine) network.30 In plain speak, it’s a giant interactive network consisting of your nervous system, immune system, the skin, and your endocrine (hormonal) system. All of these are intimately connected through a dialogue of a complex array of biochemicals.
The Boston researchers studied how various external forces influence our state of mind, from massage and aromatherapy to depression and isolation. What they discovered confirmed what many in the scientific community have known anecdotally for centuries: our state of mind has a definite impact on our health and even our appearance. People suffering from depression, for example, often look older than their chronological age. They don’t appear healthy and vibrant, as the stress of coping with depression has accelerated the aging process and damaged their health.
Since the NICE network entered our vocabulary, dozens of other studies have been performed to confirm the powerful interplay between psychology and biology or, put simply, mind over matter. An analogy I like to use in my practice goes like this: If you’re walking down a dark alleyway at night and hear footsteps behind you, you might be alerted in uncomfortable ways, and your body will prepare to fight or flee. But if you then hear your friend’s voice, everything in your body’s physiology changes in that one instant. Yet the only thing that’s changed is your perception!
So going back to the question “Can depression be good for us?” Was depression once an adaptive response to the environment? I subscribe to the idea that the body doesn’t make mistakes after millions of years of evolution. A 2014 review in the Journal of Affective Disorders attempts to answer the question