Hyposensitivity and hypersensitivity can both occur in people with bipolar disorder. Up to 35% of people with bipolar disorder experience greater sensitivity, especially when associated with longer episodes. Around 28% of people with bipolar disorder experience hyposensitivity. Unlike bipolar moods, sensory processing sensitivities do not come and go. They are persistent, but can be exacerbated by mood episodes.
Sensory processing is how a person’s nervous system responds to stimuli. This relates to all of the dozen-plus senses in the body including sight, sound, smell, heat/cold sensations, pain, pressure, hunger/thirst and taste. When any of these occur, they are processed by the peripheral nervous system (nerves) and/or the central nervous system (brain).
People experience these sensations at different intensities. Some may not be as sensitive to pain or heat while others are extra-sensitive to those stimuli. This exists on a spectrum with normal sensation perception in the middle, hypersensitivity on one end and hyposensitivity on the other. When a person generally exists on one end or the other, it may be considered sensory processing disorder. Most resources on SPD focus on children, but it also occurs in adults.
Hyposensitivity can be further broken down into two categories- low registration and sensation seeking. Low registration describes people who require a higher intensity of stimuli in order to process the information. An example of this is a having a higher tolerance for pain. Sensation seeking is when a person seeks out intense stimulation. This may be because they are hyposensitive and have a strong desire to feel intense stimulation.
Risk-seeking behaviors are common in hyposensitivity. This is also a common feature in manic episodes of bipolar disorder. It’s possible that those experiencing manic episodes are seeking a sort of perception “high” when engaged in sensation seeking. They may not necessarily be hyposensitive.
Hypersensitivity is the opposite of hyposensitivity and can also be further broken down into two categories- sensory sensitive individuals and sensation avoiders. Sensory sensitive individuals have a lower threshold to stimulation. Whereas a someone with average perception may only feel pressure, the sensory sensitive individual may feel pain, some to an intense degree. Sensory sensitive individuals may perceive stimuli at a higher intensity, but they do not necessarily avoid sensations. Those that do limit exposure to stimulating environments are considered sensation avoiders.
Hypersensitivity has been linked to anxiety, which is highly prevalent in bipolar disorder. When a person is feeling overly-anxious about a certain stimulus, an impulse may be to avoid that stimulus as much as possible, making the person a sensation avoider.
Sensory processing affects all areas of life to some extent. In Part II, find out how each of these sensitivity processing styles may affect quality of sleep and quality of life.
Image credit: Anthony