Irritability is medically recognized as the pervasive and sustained emotional state of being easily annoyed and provoked to anger.  It may be expressed outwardly in the cases of violence towards others, or directed inwards towards oneself in the form of self-harm.  This effect, especially when strong, can sometimes cause violent or aggressive outbursts in a small subset of people who may be predisposed to it. The chances of somebody responding in such a way differs wildly between people and depends on how susceptible an individual is to irritability and how well they cope with it. It is also worth noting that this typically only affects those who were already susceptible to aggressive behaviours. However, regardless of the person, this effect results in a lower ability to tolerate frustrations, negative stimuli, and other people. A person undergoing this effect may be prone to lashing out at others, fits of anger, or other behaviours that would be uncharacteristic for them sober. Irritability is often accompanied by other coinciding effects such as anxiety, paranoia, and ego inflation. It is most commonly induced during the after-effects of heavy dosages of stimulant compounds, such as cocaine  , methamphetamine  , and methylphenidate  . However, it can be a withdrawal symptom of almost any substance, and can to a lesser extent present itself during alcohol intoxication  .
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