People with ADHD display hypersensitivity to sensory stimuli from a young age; this hypersensitivity often persists into adulthood. People with ADHD do not seem to differ in sensory processing in regard to most event-related potentials; however, they do display significant differences in event related potential responses involved with late cognitive processing such as P300, CNV[disambiguation needed], Pe[disambiguation needed] which may indicate that hypersensitivity in ADHD is caused by abnormalities in the expectation of and allocation of attention to sensory stimuli. Abnormalities in later cognitive processing may contribute to hypersensitivity and the sensation of sensory overload in people with ADHD.
People with PTSD are prone to sensory overload due to a general hypersensitivity to sensory stimuli partially caused by sensory gating issues; this is supported by the fact that people with PTSD suffer from impaired P50 gating and an inability to filter redundant auditory stimuli. Irregularities in the production of and response to neurotransmitters is one possible etiology for sensory overload in people with PTSD; specifically, people with PTSD may display hypersensitivity to stimuli due to chronic homeostatic imbalances in dopamine and norepinephrine. The hypersensitivity of people with PTSD to sensory stimuli is supported by an augmented P300 event-related potential response compared to healthy controls which indicates a semi-permanent heightened attention to deviant and salient stimuli.
People with OCD display a cognitive inflexibility to changing environments. It seems that people with OCD are hypersensitive to stimuli that are indicative of negative situations, and this hypersensitivity may contribute to sensory overload. It is theorized that people with OCD have compulsions to carry out repetitive actions due to self-doubt and a desire to achieve perfection. A common trigger for compulsions in people with OCD is the perception of contamination; people with OCD commonly deal with the perception of contamination with repetitive hand washing. In a situation where a person with OCD is subjected to an environmental stimuli that elicits compulsion, such as getting dirt on their hands, they may feel overwhelmed by sensory stimuli and deal with this sensory overload through mitigating the stress with compulsions such as repetitive hand washing.
People with schizophrenia are prone to sensory overload since people with the condition cannot divert their attention from repetitive and unimportant sensory stimuli. The inability to focus on relevant stimuli and filter out unnecessary and excessive sensory stimuli displayed in schizophrenics is due to physiological sensory gating issues, and the paired click P50 test can be used to determine if an individual has abnormalities in sensory gating and is therefore prone to sensory overload. A proposed theory that explains sensory overload in schizophrenic patients is that abnormalities in alpha-7 and low affinity nicotinic acetylcholine receptors prevent normal transduction pathways between the cortex and hippocampus that facilitate sensory gating.
People with misophonia display hypersensitivity to certain pattern-based noises such as the sound of chewing, slurping, finger tapping, foot shuffling, throat clearing, pen clicking, and keyboard tapping; people with misophonia respond to triggering sounds with emotional distress and increased hormonal activity of the sympathetic system. When people with misophonia are subjected to noises that trigger misophonic responses, they feel as if they are being overloaded by auditory stimuli and seek to escape from or block out the triggering noise. Compared to healthy controls, people with misophonia display a lower N100 peak in response to mismatch negative (MMN), but this is not a reliable biomarker for the condition and sensory overload. A more reliable indicator that hints at proneness to sensory overload is heightened activation of the anterior insular cortex which is evoked by trigger noises and can be measured by fMRI; the anterior insular cortex may be involved with the pathway that gives rise to the sensation of sensory overload in people with misophonia.
There is evidence that the visual cortex of people with grapheme-color synesthesia is more excitable than that of typical people; additionally, people with grapheme-color synesthesia respond more strongly to visual stimuli compared to people without the condition. People with grapheme-color synesthesia report feeling visual stress and discomfort in response to gratings of mid and high spatial frequencies, correlating to a sensory overload response evoked by intense visual stimuli.
People with general anxiety disorder are highly sensitive to external anxiety triggering stimuli and deal with exposure to these triggers through neurotic thoughts. People with GAD are biased to perceive sensory stimuli as negative or threatening and this bias feeds into negative thought processes which further exacerbate feelings of worry, stress, and anxiety. People with GAD are hypersensitive and hypervigilant to ambiguous, neutral, and emotional stimuli and often compartmentalize such stimuli as negative. People with GAD are prone to sensory overload when in novel settings or interacting with new people since ambiguous and neutral stimuli in these instances are usually processed as threatening or negative; adolescents and children with GAD are especially avoidant of and distressed by novel stimuli which is theorized to be elicited by either a hyperactive sympathetic nervous system or an under-active parasympathetic nervous system.
People with autism suffer from auditory hypersensitivity which can lead to sensory overload. Although people with autism do not suffer from abnormalities in P50 sensory gating, they have anomalies in sensory gating related to the N100 test which indicates an irregularity in attention-related direction and top-down mental pathways. It is speculated that disturbances and issues with directing attention towards relevant or salient stimuli, evinced by deviations from standard P200 and N100 responses, is partially responsible for the sensation of being overwhelmed by sensory stimuli in people with autism.
It has been suggested that people with Tourette syndrome have a hypersensitivity to bodily sensation that originates in higher order processing partially the result of distorted and higher than average amplitude of afferent somatic signals. People with Tourette syndrome sense urges to do tics that are often localized to regions of the body that carry out the tic response. It is theorized that tics might be caused by sensory processing issues where sensations trigger movements which manifest as tics. Additionally, people with Tourette syndrome display a moderate inability to inhibit distracting stimuli which might lead to sensory overload. People with Tourette syndrome may be prone to carry out tics in an environment of overwhelming sensory stimuli.
People with fibromyalgia are hypersensitive to intense stimuli such as bright lights, loud noises, perfumes, and cold temperatures; people with the condition also have hyper-excitable nociceptors. When people with fibromyalgia are subjected to intense stimuli, they experience sensory overload in the form of pain. It is theorized that abnormal activity of the left dorsolateral prefrontal cortex and reduced production of or reception to serotonin are partially responsible for the sensation of pain in response to intense stimuli.
People with chronic fatigue syndrome display a hypersensitivity to noxious stimuli, stress, and pain. These sensitivities are partially explained by abnormal neurotransmitter pathways involving serotonin and acetylcholine. When people with the condition are exposed to intense stimuli, they report pain, fatigue, nausea, and reduced cognitive abilities; chronic sensory overload causes the sensation of brain fog.