Adrenaline junkie

Colloquially, an adrenaline junkie is somebody who appears addicted to adrenaline. Adrenaline in this case comes from an endogenous source (i.e. the adrenal gland) and does not imply the use of exogenous adrenaline (e.g. injection).

The term came into use in 1993. Originally, it was used to describe argumentative people who deliberately (consciously or unconsciously) find excuses to explode in order to get an adrenaline fix. This mode of receiving a fix is deemed just as addictive as a recreational drug (such as heroin, hence the term "junkie"), but perhaps more harmful as it negatively involves other people. The phrase adrenaline junkie was used in the 1991 movie Point Break to describe the "Ex-Presidents."

Adrenal glands
Adrenaline junkies enjoy engaging in activities that stimulate the adrenal glands, which are responsible for producing a broad spectrum of hormones which cause the stress response, also known as the fight-or-flight response. Adrenaline is the most well-known hormone in this family, although each of the hormones, including noradrenaline, cortisol, and various other catecholamines and corticosteroids, play a part in the stress response. The effects include hyperarousal, increased blood flow, heightened pulse rate, and increased physical performance, which adrenaline junkies find an enjoyable and invigorating state of mind and body.

Activities
Any number of extreme sports or dangerous activities could be associated with the phenomenon, such as streetluge, dirt bike riding, skateboarding, Longboarding, skydiving or rock climbing. Some prefer more aggressive activities such as picking fights. Less physical pursuits would include gambling, stock market trading, graffiti, or even shoplifting.

When a person stops doing such things they can often go in to a withdrawl. In extreme cases even resulting in a stay at the hospital.

Pharmacokinetics
Although the term "adrenaline junkie" is normally used facetiously and without any genuine implication of addiction, there may be an element of truth to the description. Psychological addiction to an "adrenaline rush" has been reported numerous times. This can result in cravings, depending on the individual. Physical dependence to adrenaline does not seem to develop, so withdrawal symptoms are not present.

An adrenaline rush is usually accompanied by an increase in endorphin activity. Endorphins are responsible for feelings of well being, as well as pain relief. Due to synaptic plasticity, increased endorphin activity creates an increase in endorphin receptor sites, which in turn can create a stronger desire for endorphins. Synaptic plasticity and receptor site proliferation are widely believed to be the mechanisms by which chemical addictions are developed.

However, the same can be said for any endorphin-stimulating activity, whether laughter, physical exertion, sexual intercourse, artistic expression or religious experience. Although synaptic plasticity may be responsible for chemical addictions, it is also believed to be involved in reinforcement, the mechanism by which animals learn to differentiate what is desirable from what is undesirable. Seen in this context, chemical addiction could simply be seen as an aberrant form of plasticity.

Although the effects of adrenaline are largely positive, increasing cardiovascular activity and oxygenation, extended or chronic adrenal stimulation can eventually lead to high blood pressure, heart disease, and other stress-related diseases.