My friend, Vihan, was young, attractive, and fit when I met him 15 years ago. So, of course, when he offered to take my body to the next level of fitness, I took him up on it. He is a brilliant teacher. He’s patient, kind, and mild-mannered. But he’s also a liar.
“OK, just one more,” he’d say with the encouragement of a life coach.” I was committed to my endeavors of health, endurance, and sexiness. So, I’d psych myself up and muster that last ounce of strength to do one more pushup, one more bench press, or one more minute on the StairMaster. But just as I’d finished and my muscles were collapsing from exhaustion, he'd say with his inspirational calmness, “OK, just one more.”
With my last breath I’d call out, “Bastard!” And then he’d pull the barbell off my neck and place it back on top of the bench. I fell for his one-mores every week at the gym until the day he pushed me so hard I ran outside the gym and fell prostrate on the sidewalk soaked in sweat, on the verge of vomiting. “No more,” I squeaked. My mind was willing, but my body simply wasn’t capable of going any further. It had been pushed to its limits. Ultimately, I was forced to make peace with a lower bar of sexiness.
Try though we might to lift our own mood or push out an image of mental health to people around us, a strong will and positive thinking will only take us so far. The body has physical limitations. My swimmers physique will never win a bodybuilding contest, no matter how many protein shakes I consume. I will never be an astrophysicist, or a machine learning engineer, because that’s not how I think.
Likewise, we have to remind ourselves that our mental state is a physical state. Our minds are not disconnected from our bodies. Our consciousness and thinking comes from our real, physical brains, which are the command center for everything else that happens to us.
The causes of depression are complex. But knowing about the neuro and biological components helps us "name the disease" so to speak. The disease becomes more tangible for us and our loved ones. We are not making it up, nor looking for attention. Instead, we and our loved ones need the same compassion, empathy, and patience of someone who has cancer or heart disease. Those of us who suffer also need to practice self-compassion and grace. And information is power.
Over the last ten years, scientists have put much more of their attention on the confluence of genetic and environmental factors when it comes to depression and mental health. This includes looking more closely at our biology, neurology, and lived experiences that interact with, cause, and/or exacerbate depression. Identifiable brain anomalies have been found that empirically impact our mood, decision-making, and the way we relate to the world.
I'm going to list a few of them here while inviting you to do your own scholar.google.com research. Unless you're a neurologist or well-versed in brain parts and functions, you'll notice these studies take quick, sharp turns into the weeds. You'll need a seatbelt. And a thesaurus. A glass of wine wouldn't hurt.
The Frontal Lobe
The frontal lobe of the brain, responsible for cognition and mood regulation, along with corresponding structures, “has been considered to be the most common region to manifest anatomic abnormalities in major depressive disorder” according to researchers. These areas show decreased thickness in the prefrontal cortex and less gray matter. Both are correlated with depression and reduced brain activity, which normally helps regulate response to negative stimuli. The frontal lobe is also responsible for restraining "redundant, or uncomfortable neural activity, feelings and behaviors, and plays a crucial role in emotional/motivational management and decision-making," these researchers say.
A lesion on the dominant frontal lobe, which can be caused by a wide variety of events, such as traumatic brain injuries or medical procedures, can also impair frontal lobe function. Researchers said, "Since the frontal lobe governs memory, emotion, judgment, executive functions, and behavior, a lesion of this lobe is the most common cause of depression or other mood disorders. A lesion of the dominant frontal lobe is more likely to cause these disorders."
The Orbitofrontal Cortex (OFC)
The orbitofrontal cortex (OFC), which inhibits “background-independent, redundant, or uncomfortable neural activity, feelings, and behaviors” is what we rely on to manage our emotions, motivation, and decision-making. However, the right, medial part of the OFC has been found to be thinner in people who struggle with depression and brain activity was reduced. Decreased gray matter in another section of the OFC, the left middle frontal gyrus, was found to be an area “associated with emotional bias, apathy, and loss of motivation.”
Depression, like other mental illnesses, is often exhibited through our emotions, which during episodes can feel like riding stormy ocean waves. Scientists define emotions as “acute reactions to threats or opportunities that manifest as loosely coordinated changes in experience, behavior, or physiology.” These emotions are generated by the limbic system in our brains. While there is some disagreement about all the various components that make up the limbic system among neuroscientists, the four main components include the hypothalamus, amygdala, hippocampus, and thalamus.
The hypothalamus regulates our body temperature, mood, sex drive, as well as sleep, hunger, and blood pressure. It listens to nerve cells in our brains and bodies and controls the basic functions by communicating with our nervous system or hormones. Many of the things we take for granted as part of our autonomic nervous system, such as breathing, heart beat, and controlling our bladders and bowels, are regulated by the hypothalamus. This process is called homeostasis.
The amygdala works as the core of our neural system. It processes fearful or threatening stimuli and helps our brain decide what to do next. Most commonly, this is called the fight or flight mechanism. The amygdala is almost always active in people with depression, activated as we ruminate, feel anxiety, and try to process strong emotions. It's that fear that often keeps us feeling trapped or lashing out at people around us when we're feeling unsafe.
The hippocampus lies deep within our brains and holds a major role in learning and memory. While it exhibits a high degree of plasticity, it is also vulnerable to damage from stimuli, such as psychiatric disorders. Depression, in fact, has particularly wreaked havoc on this essential function. Neuroendocrinologist Robert Sapolsky said, “Few medical maladies are as devastating in their effects as major depression.” Hippocampal volume loss has been noted up to 20% and “helps explain some well-documented cognitive deficits that accompany major depression.”
Finally, the thalamus takes in information from our senses and sends the information to the cortex, which is the thinking part of our brain. The thalamus also keeps us awake and alert and plays a role in thinking and memory. Psychiatrist Bessel Van Der Kolk, author of The Body Keeps The Score, said:
“Sensory information about the outside world arrives through our eyes, nose, ears, and skin. These sensations converge in the thalamus, an area inside the limbic system that acts as the “cook” within the brain. The thalamus stirs all the input from our perceptions into a fully blended autobiographical soup; an integrated, coherent experience of “this is what is happening to me.”
Depression is like driving a sputtering car that has a faulty wiring system. It stops and starts. It's fast and then it's slow. Some days it drives like a well-tuned sports car and other days it doesn't work at all. We'd love a new one, but for now our only hope is to figure out what's wrong with the one we have and keep working on getting it fixed.