Anxiety or stress leads the brain to process information differently. Basically, stress causes you to think fast, rather than to think comprehensively. Working memory and the ability to carry information through time is adversely affected by acute stress, even if the stressor only lasts for a few minutes. The transient changes are mostly chemical but prolonged stress measured in days or weeks actually creates physical changes to the brain and its neurons. Depending on severity and duration, stress can lead to irreversible modifications in thought and cognitive ability. The stress hormone cortisol is the main culprit and it makes alterations all over the brain particularly in the hippocampus and prefrontal cortex. I have written at length about this here:
I believe that I have personally experienced what it is like to lose mental aptitude to stress. I want to take the opportunity to offer some anecdotes from my experiences because, however subjective, I feel that they may offer insight for the psychotherapist and the philosopher, if not the clinical neuroscientist. I have been fighting severe stress for several years and what follows is a memoir on the cognitive dissolution that I withstood.
Over the past five years, I have endured several month-long bouts of chronic stress. In the morning I would wake up feeling anxious, and after just a few social encounters, my heart would be racing and my adrenaline overpowering. Many friends and acquaintances were often surprised by the way I appeared to behave like someone who was panicking for no apparent reason. I tried to compose myself, but struggled because my anxiety was extreme and excessive. Despite concerted attempts to combat stress I would often feel overwhelmed by it for days at a time. I believe that early on I was not fully aware of (I was anosagnosic of) some of the psychological changes that were taking place. After noticing that I was having memory lapses of unprecedented magnitude I began to carefully observe my mental handicaps and measure my performance relative to my premorbid state. Doing this, I believe, allowed me to identify and analyze many of the neuropsychological corollaries of my predicament. I am convinced that, to an extent that is objective of hypochondriacal concern, my attention-span, working memory, declarative memory, and my ability to learn and exercise discipline declined gradually over a period of a few years.
My ability to concentrate was one of the first faculties adversely affected by stress. Prolonged concentration is impossible if the train of thought is persistently derailed. After days of intense anxiety I felt like it actually became harder and harder to remember what it was that I was just thinking. It was the same with reading. I could not conceptualize long complicated sentences because, before I finished the sentence, I had already become oblivious to the first few phrases. My reading comprehension became worse and worse because previous sentences and paragraphs were not immediately available. Reading erudite academic texts was previously challenging and rewarding, but the chronic stress made it prohibitively difficult. When I tried to concentrate on, or grapple with, a question that I posed to myself, I found that within a few seconds, I lost the train of thought. Before I could pin down one concept and evaluate a second concept relative to it, I had already lost attentive command of so many of the relevant features that the effort was useless. I could not collect my ideas on subjects that I was reading about or even wondering about unless I was intensely intrinsically motivated. It was a state of constant intellectual exhaustion.
Because I could no longer pose difficult questions to myself and systematically identify the avenues that would help me answer them, I had fewer interesting insights. The conclusions I reached were trivial and insubstantial. In fact, most of my interesting ideas were accidental, and made through snap judgments instead of earned through inductive reasoning. When I tried to apply rationale, I returned quickly to zero - returned to my physical senses. Instead of being able to become “lost in thought,” I was grounded in physical immediacy. At first it felt as if each new thought was powerful and interesting, but I soon realized that it only seemed this way because previous thoughts faded prematurely. I was distractible precisely because previous thoughts abandoned me before they could perform their function of keeping me on track. Rather than being able to find my mental considerations captivating, I found myself looking around at my surroundings and thinking about how I could attain cheap, quick stimulation. Dedicated and disciplined work became too difficult to persevere through, but I didn’t lose my drive, it was simply refocused towards endeavors with short-term payoffs. The things that would capture my interest appeared important at the time, but it didn’t take long for them to be revealed as shortsighted impracticalities. As I became increasingly shallow and capricious, my activities became unproductive, foolhardy, and even self-defeating.
Epiphenomenally, it felt like the window through which I brought the immediate past had become narrower. Only the very salient or heavily familiar concepts could make it through the gap. I had trouble recalling my last notions, sometimes, even if they were mildly promising or exciting. It seemed that even things that I had been exposed to a few seconds prior, had little or no bearing on my subsequent responses and perceptions. My behavior began to hold similarities to hypofrontality syndromes or with the “environmental dependency” of patients with PFC injury in the sense that I acted as if I had fewer internal representations and an exaggerated dependency on the external environment for behavioral cues. The internally driven perceptions that I experienced lingered only briefly before they were irretrievable. It was as if my mind’s ability to juggle activated engrams was compromised and now an engram that was just present in the volley, would disappear before it could make its proper contribution to thought.
I would come to a point in my thought process where I would try to recall a recent event. I had a couple of cues, enough to assume that, based on past experience, these cues would be sufficient to recruit the rest of the memory. A second would pass… a few more seconds pass… then nothing, no recollection at all, as if the mechanism normally responsible was utterly broken. It seemed like my memory worked either instantaneously, or not at all. If I could not recall something I was trying to remember right away, it would be useless to spend more time trying to refresh the memory. This reminded me of the condition common in prefrontal brain injuries where the patient cannot voluntarily cue up memories from the hippocampus using their PFC, but the hippocampal memoires can be jogged from environmental cues (from the sensory cortex) rendering recollections superficial and rendering associations loose. I realized that my working memory deficit probably led to the recall deficit: Because previous thoughts vanished quickly over time, related concepts could not accumulate to the point where they are able to coactivate or converge upon the associated memory in question. This may be related to the fact that I could either recollect something all at once, or not at all.
I was able to recall a much smaller proportion of the new things that I had learned and could only remember things if the recall cues were numerous. For instance, if I forgot a grocery list, I would not remember the items unless I actually saw them in the market (recognition without recall). Another difficulty that was very foreign to me: after I learned the meaning of a new word it wouldn’t stick, although the word itself might appear more familiar. Instead of assimilating the semantic features immediately, I required many encounters with a new word for the content to consolidate into long term memory. My working vocabulary, the repertoire of words that I can access in the middle of a conversation, was vastly reduced. At first I began to wonder if this might reflect the fact that I wasn’t reading as broadly or working hard enough to maintain my working vocabulary, but it became painfully clear from the shear extent of the loss that it must be due to the stress. I felt like my condition was very similar to what I have read about anterograde hypomnesia. When I was trying to remember something that I had read about or had been exposed to I often could remember how I felt about it emotionally, but many of the episodic and contextual features were irretrievable. Often I could remember something that was said, but I could not remember who said it, or where I was when I heard it. This phenomenon was striking.
This absence of contextual features effectively made it very difficult to do reality testing. I would have a recollection of something, but I would not be sure if it really happened because I could not recall details about the situation. I could not recall whether this event actually took place, was a dream, or was a hypothetical scenario that I had imagined. It became particularly disconcerting when I realized that my reduced capacity for reality testing began to lead to delusional thinking. I would catch myself devising absurd and unrealistic explanations for my actions – confabulations of a degree and severity that were previously foreign to me. I would act in ways that might seem reasonable to someone who cannot see the whole picture, using associations that are applicable in one respect but irrelevant in others. Such superficial associations would cause me to act before I noticed that my action disregarded or flouted more important concerns and norms. I believe this process probably lies at the heart of psychotic impulsivity. I noticed that I would begin to feel an impelling brand of certainty after reaching absurdly premature conclusions. Mere chance coincidences felt ominously significant. When this happened I would have to use reason and patience to fight the overwhelmingly convincing sham certitude. This quasipsychosis, most pronounced during stressful days, was even accompanied by minor auditory and visual hallucinations. Imagined sounds and sights felt exquisitely real momentarily in ways that they never had in the past. Moreover, I would analyze misperceptions, as if they were correct, for inordinately long periods before I recognized them for what they were.
The stress started to become so bad that I began to experience perceptual errors. I continually thought that I was seeing my cat in the corner of my eye but every time I looked it was really a shoe or some dark object on the light carpet. I actually mistook normal household or neighborhood noises to be human voices. At its worst, on days when caffeine greatly exacerbated my stress, sometimes I was totally immersed in my sensory experience to a point where it felt like I didn’t have thoughts of my own. It felt like because I had lost much of my internal monologue, that I had become one with my environment (this sensation probably involved hypofrontality). If I felt this way during an interaction with others I would struggle to hold a reasonable conversation and much of what I would say would be non-sequiturs. I still cannot drink caffeine because if I do, I practically begin to panic (caffeine is a central nervous system stimulant that acts through the effects of the stress hormone system).
Before experiencing chronic stress I could analyze and evaluate a hypothesis in my head alone, now I have to write about it. I must work an idea out on paper in order to get a feeling for whether it is right or not. Before the stress, most of my thinking used to be visual, it was rarely verbal. Using language was an impediment in the sense that the time needed to form words into sentences slowed down my thought processes. Now I have to put all of my formal thoughts into words because I need the crutch of language and the phonological (articulatory) loop to act as memory buffers to be able to hold concepts in mind. I also feel like my actions, behaviors and speech come out very quickly as if preformed, especially for familiar actions. In the past a single action was broken down into many separate elements, each of which I had some attentive control of or acknowledgement of before they were issued. Now I look back after acting and wonder how all of those elements came together without planning. Interestingly, this only happens in areas I am experienced in. When I am forced to act in an unfamiliar environment or with novel conceptual constructs, I either falter and struggle or speed through it in a crude, poorly integrated way. Because I notice myself doing things without contemplating first I know that I have lost degrees of personal free will and have experienced an accelerated disintegration of self. In many ways I feel as if the person that I was previously is now gone.
My working memory was lacking terribly, but implicit (habitual and procedural) responses actually filled in many gaps quite well. For instance, trying to learn or interact with new systems (such as a new computer operating system, a new bicycle, or a new supermarket) was very difficult and frustrating, but interacting with familiar systems was effortless. Because of this, I eschewed novelty. As long as I stuck with familiar territory I was able to get along well without other people noticing my deficits. My spatial ability, which works somewhat independently of implicit and habitual memory, was one of the faculties that deteriorated most noticeably. I used to be able to walk deep into the journal stacks in the university library basement, absorbed in articles, while at all times keeping my spatial and temporal bearings. No matter how many turns I had taken down windowless corridors I always knew where I was and which direction the compass would point. Today, only a few years later, I can quickly lose my sense of direction and orientation, even outdoors and even in the presence of salient landmarks.
The most interesting part of all of this is how normal I seem after a tremendous loss. The other brain areas, programmed by the cortex, allow me to move, act, speak, even hold a conversation and to an outsider, nothing seems to be missing. Externally it is very hard to recognize, but internally I feel that I am missing an entire world of planning, insight and foresight. I have lost the mental leverage that helps me to make complex and unique associations that are different from other associations that I have made in the past. A few years ago, I felt that my conscious life was mostly planning actions and envisioning the future. Today it is mostly having fleeting insights about the repercussions of my actions – automatic, mostly unplanned actions mediated more and more by lower brain systems.
Once my higher-order intellectual faculties were diminished, I could not will them back. I couldn’t do anything to revert back to the old me. This insight dispelled the last dualistic inclinations within me and proved that my previous mental abilities were materialistic and not at all voluntary. PFC mediated thought is as involuntary, transient, fleeting and insubstantial as lower-order cognitive faculties are. Executive processes could be taken away by the stress cascade because they were not inherent in who I was, but were on a fundamental level automatic and reliant upon their neural substrates. This made me realize that my previous intellect was never earned or willed, it was simply biological chattel.
Before the stress, I was socially inept in many ways; I came across as spacey, stilted, abstract and neurotic. I used to think very hard before I spoke in virtually every social situation. I would even formulate nearly every sentence in my mind before I spoke it. I cannot do this anymore. Now I have to start a sentence before I know how I am going to finish it. It got so bad that I began to frequently lose my train of thought in the middle of conversation. Every time I strayed too far from my topic I would, embarrassingly, not be able to come back to my main point. Formulating long, descriptive sentences could be agitatingly difficult. Now when speaking, I am forced toward brevity and simplicity and made to relinquish hope that I will be able to recall unique technical terms that lack substitutes. Often I know that there is a specific word that I am looking for but that I will not be able to cue it up on the spot. Sometimes it seems like the only words that I can trust to fall into place are those common and habitually ingrained ones that I have been using since childhood.
After awhile, I learned to simplify my discourse and to stop trying to set up complicated arrangements of sentences. I say things that I have already said before, retell the same stories to different people, employ melodic contour, use trite expressions and more emotionality and never veer off too far from the main point, for fear of losing my train of thought. Ironically people responded better to this, and I noticed that I quickly became more socially facile. I was more affectively congruent (a largely implicit ability), and instead of being stilted and detached during conversation, I was able to maintain a high level of emotional fluency which at times helped me build rapport with other people better than I had ever been able to prior. Instead of seeming suppressed, excessively conscientious and calculating, I came across as more emotionally impelled and thus more authentic. Instead of being informed by thoughtful analyses a very large proportion of my speech was simply composed of “dominant responses” which consisted of the easiest thing to say in each situation – the first thing that comes to mind. My newfound ability to be spontaneous, to improvise and to respond without really thinking much made my social interactions much more comfortable and easy. It also made simple motor movements perceivably easier
Many but not all of the effects of stress on cognition are reversible. The altered dopaminergic response to stress can reverse within a few hours of the stressor; the dendritic retraction appears to reverse after several weeks but the death of hippocampal neurons may not be reversible at all (Sapolsky, 1996). How can we determine the extent of irreversible damage? It seems to me that I have recovered some lost function, and I credit many sources. Mindful meditation, heavy cardiovascular exercise, caffeine and cigarette cessation, abstention from violent video games, yoga, Buddhism, ego-restraint, positive psychology, biofeedback, and efforts at increasing my social support network have all seemed to help me tremendously in my efforts to reduce and recover from stress.