Does Concussion Cause Mental Illness?

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Many years ago, I said to one of my doctors that I believed undiagnosed and/or untreated brain injury causes much mental illness. If we treat the neurons, then the illness will clear up. He hadn’t thought of that before. I hypothesized further: Many people wouldn’t remember concussions in childhood or adolescence or would’ve dismissed them as no big deal, leading to doctors either not knowing about them or not connecting them to current problems. Yet concussions activate microglia.

“In response to challenges, such as tissue injury, pathogens, or other pathological processes, microglia quickly respond to the homeostatic imbalance and undergo considerable morphological transformation to provide defense mechanisms….The number of transformed microglia increases, and they migrate to the injured site at a rate of 1–2 μm/min for tissue repair. The activated microglia gradually shift from providing nutritional support and repairing neurons to neuronal dysfunction. These changes in function may be more persistent after continuous exposure to certain stimuli....Dysfunctional interactions between neurons and microglia are critical factors in severe neurological disorders, including depression, schizophrenia, and [Alzheimer’s].” (Wang et al)

In 2019, Murray B. Stein and colleagues studied mental health in 1,155 people who’d suffered mTBI (mild traumatic brain injury) three, six, and 12 months post-injury. Their study revealed that “approximately 1 in 5 individuals may experience mental health symptoms up to six months after mild traumatic brain injury (mTBI), suggesting the importance of follow-up care for these patients.”

Back in 2000, my neurorehabilitation team told me that depression is common in patients like me; I was unusual in not showing depression. At the time, I wasn’t aware of microglia response to injury; I accepted the correlation as due to the social, personal, economic, and other consequences of the injury, not direct injury-induced neurophysiological changes as causation.

Wang and colleagues further noted in their paper: “Recent studies have suggested that depression can be regarded as a microglial disease. Microglia regulate inflammation, synaptic plasticity, and the formation of neural networks, all of which affect depression.”

A few years ago, I read The Angel and The Assassin by Donna Jackson Nakazawa, a well-researched book detailing microglia, the research behind their discovery, and the resulting clinical innovation in treating mental illness. She wrote:

“Microglial cells developed the ability to mount an immune offensive in the brain in order to help you heal, and to keep you and your family safe….as your body begins to successfully battle the infection, microglia continue to spew forth inflammatory chemicals in your brain, causing changes to neurocircuitry that change your behavior too, that likely prompt you to experience a complete loss of interest in life—or anhedonia….That, it turns out, is a pretty neat evolutionary trick.”

By creating anhedonia or depression, by making you feel like not moving, socializing, or engaging in activities you usually enjoy, microglia prevent you from spreading disease and let your body use all its resources to heal. You get better quicker.

But the community doesn’t need protection from you when injured; yet you still need to use all your resources to heal. Nakazawa writes that traumatic insult to the brain or spinal cord generates inflammation in the brain for months or years. Inflammation is microglial activation that obliterates the synapses, destroying the neurons on either side of those synapses. The symptoms generated depend on where in the brain microglial activation occurs. Microglial activation not only creates behavioral changes, but where it occurs after brain injury can also damage emotion centers and mood-related networks.

What about my hypothesis, then, that much mental illness is untreated and/or unrecognized concussion in childhood or adolescence or any trauma that induced microglial activation? Is it correct to call depression a microglial disease since the microglia are behaving the way they should in response to injury, viral illness, trauma, or any brain insult? What about adults who receive a later-in-life diagnosis of attention deficit disorder? Or anxiety disorders or depression? The problem isn’t microglial activation; it’s their chronic activation and non-return to healthy activity. I hypothesize that rather than a disease of the microglia themselves, it’s that clinicians failed to treat the underlying cause expeditiously and reboot the microglia.

“This is no doubt why the serotonin theory of brain disorders has not really turned out to to be the great hope it was initially thought to be: Chemical imbalances are not the root of the problem, but a symptom of it….If, instead we can keep microglia in a healthy state of homeostasis, or reboot them to a healthy state, then we can help…keep neurochemicals in balance and nurture synaptic health.” (Nakazawa)

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But to determine how microglia are behaving, clinicians must run objective tests. The DSM-V, by focusing on external symptoms, cannot peer inside the brain’s neurophysiology. Accessible and inexpensive qEEG does by showing areas of slowed and abnormal brainwave activity that reflect neurocircuitry loss from microglial activation. “This loss of circuitry," Nakzawa writes, "can be measured by the brain wave patterns that emanate from the underlying DC [direct current] field."

Do healthcare professionals routinely assess brain activity after any (past) hits on the head, “just a whiplash” in a car crash, domestic violence, or other causes of brain injury? Do they conduct qEEGs or evoke potential studies as part of their assessment? They do for epilepsy and sleep problems but, strangely, not for concussion or mental illness. Unfortunately, clinicians still treat specific persistent symptoms as independent illnesses instead of using neurostimulation to treat the global underlying cause and reboot microglia.

But focusing on the symptoms, as has been the standard for decades, doesn’t work. If focusing on the symptoms worked, mental illness would be treated easily and cured. Symptom management tends to be chronic, while cause-focused treatment tends to be curative.

Rebooting the microglia with time-defined neurostimulation and neuromodulation instead of managing them indefinitely leads to a better quality of life. Isn’t restoration over symptom management better health care?

Copyright ©2024 Shireen Anne Jeejeebhoy