The general pathological mechanism of mental illness can be described as a self-reinforcing feedback loop. On the Fourth of July, the politician gets up on the podium and tries to begin his speech. Suddenly there is a piercing squeal from the speakers, and, as he speaks, it only gets worse. Very simply, the sound of his voice enters the microphone, is amplified, emerges from the speaker, and is then picked up through the overly sensitive microphone and repeats this circuit, building up into an escalating screech in an instant. Either a sound barrier has to be placed between the microphone and the speaker, or the volume must be turned down so the microphone can no longer pick up its own output. I came to believe that psychiatric medications, such as Prozac, effectively “turn down the volume” of the hyperactive emotions to the point at which they can slip back into their properly regulated function.
The pathology of runaway feedback loops occurs when their regulation fails. The simplest examples of feedback regulation are hormonal systems in which the substance that stimulates the production of a hormone is inhibited by the hormone itself. As the level of the hormone becomes too high, it causes a decrease in the level of the substance that stimulates the hormone’s production, and thus the hormone’s level is regulated downwards. Perhaps one of the most common mechanisms in all of medical illness, at a molecular level in cancer and between hormones in some hormonal disorders, is the escape from this kind of feedback control into unregulated, runaway feedback. I am merely suggesting that this same pathological mechanism operates at the highest neuronal levels in mental illness.
Consider two individuals having an argument:
each is making the other angrier, but each is also restrained by social anxieties; as the quarrel escalates, these restraints might fail and unfettered violence might ensue. In the case of mental illnesses the analogy of feedback between a microphone and speaker is particularly appropriate because emotions bear similarities to sound: both escalate into an intolerable screeching pitch. Technically, this pathologically self-reinforcing mechanism is called a positive feedback loop, but this term seems inappropriate for a process that causes the horror of mental illness, so I call it:
Because I am introducing a new term here it is helpful to be thoroughly familiar with the meaning of these two words—and my use of them. The word feedback is well known in modern parlance and means an independent response from another party; we might say that we want to “bounce something off you.”
The word reverberation adds two elements to the concept of feedback. The first is the idea of forcefulness or intensity. The Latin root is the noun verber, which means a whip or lash; then the verb verberare, meaning to strike or beat, and finally reverberare means to strike back. The second element is that of a continuing push-back process, or vibration, particularly with respect to sound. The first entry in the Oxford English Dictionary is from Geoffrey Chaucer’s Summoner’s Tale (1604): “The rumbling of a fart and every soun Nys but of Eye reuerberacion.” Translated: “The rumbling of a fart, and every sound, is nothing but the reverberation of air…” And as long as this earthy chord has been struck, another apt example of feedback reverberation is sex leading to orgasm. Much of mental illness can be compared to a sustained orgasm but comprised of intensely painful fear, not pleasure. So in combining these two concepts, the interactive loop in feedback is further distinguished by a rapidly escalating frequency and intensity in reverberation.
So the question naturally arises: if mental illness consists of hyperactive emotion,
why do mentally ill people often have no initiative or energy to do anything?
That will be the question to be answered in the next post.