Insanity, Kaysen writes, comes in “two basic varieties: slow and fast.” She argues that the names for various types of insanity (depression, catatonia, mania, anxiety) do not actually say much about how these varying insanities feel. The slow form of insanity feels “viscous:” experiences are thick, perceptions are dull, and time drips slowly through this “clogged filter.” Velocity, in contrast, speeds up the body and creates “too much perception,” as well as an accompanying “plethora” of thoughts about the complexities of thoughts themselves.
Susanna tries to communicate how different types of mental illness present and feel. She has been through periods of both velocity (speed and mania) and viscosity (slowness and depression.) Perception is at stake and subject to change in both states of mind, and both are exhausting to the sufferer in different ways.
Though viscosity and velocity are opposites, Kaysen writes, they often look the same. While viscosity causes “the stillness of disinclination,” velocity inspires a “stillness of fascination.” Repetitive thought is common to both speeds, and an “avalanche of pre-thought thoughts” can come out of nowhere whether one is mired in velocity or viscosity. These repetitive thoughts, Susanna writes, have no meaning, and are simply “idiot mantras” which trigger one another in a domino effect until one is effectively buried beneath them, trapped in a “blunted” haze of circuitous thoughts which eventually take on the quality of elevator Muzak.
Homing in on her point about the mirroring between reality and perception that can occur in mental illness, Susanna describes how velocity and viscosity can appear the same but are actually very different sets of feelings and emotions. The effect, however, is the same—these states of mind numb the sufferer to the world around them, either through endlessly turning inward or a refusal to look outward.
Kaysen wonders whether it is worse to overload or underload, and notes that the two poles of insanity would assert themselves at varying moments, rushing or sometimes dribbling through her before quickly passing on. Susanna wonders where these thoughts came from and where they went when they left her, and considers this the “great mystery of mental illness.”
Susanna’s own suffering from periods of both velocity and viscosity has left her with painful memories of both, and no desire to experience either again or be forced to choose which “speed” she prefers.