At one level addiction is simple to understand. It starts, necessarily, with the repeated use of substances that have particular effects on the brain and mind. Some of the substances e.g. tobacco and cannabis are naturally occurring or, like alcohol, are produced through natural processes such as fermentation of grapes or cereals. Some are pharmaceutical substances or otherwise chemically manufactured. A more modern form of addiction is that due to a repetitive activity such as gambling or gaming.
Substance use is rarely, at first, a solitary activity. In all human societies, alcohol consumption (for example) is most likely to occur in a group setting, particularly amongst friends and peers. There are important social and cultural influences on the uptake of a particular substance - be it alcohol, tobacco, marijuana, ecstasy tablets, coca leaf or betel nut.
People with addictive disorders experience feelings of loss of control over their lives. Research has identified key circuits in the brain that are responsible for the increasingly powerful grip addiction has on an individual. The neurocircuits that are the anatomical location of addiction are located in the mid-brain and the lower forebrain. There are four key neurocircuits that, in response to repeated use of a substance, become physiologically altered or “re-set” in an enduring way.
1. The reward circuitry
The reward circuitry becomes progressively “hijacked” by use of that substance, with the result that other enjoyments (food, love, sport, sex) become blunted and dull.
2. The alertness system
Many substances suppress alertness (alcohol for example) and repetitive substance use will cause adaptive changes in these pathways resulting in a heightened state of arousal or excitation.
This helps to explain the common feelings of hyper-arousal and anxiety that occur in persons with addiction.
It provides an explanation as to how people with addictive disorders are triggered by the site, smell or taste of their preferred substance and can be triggered also by environments associated with alcohol consumption (for example) or groups of friends or environments such as a pub or club, or even unpleasant internal feelings.
As addiction develops, priorities change and can do so fundamentally. Changes in the salience neurocircuitry result in substance abuse and activities associated with it. Activities that once had high priority become relegated to the periphery.
4. Behavioral control
With the development of addiction, there is progressive weakening of behavioral control pathways. Loss of control over substance use and having no brake put on them are the results. Substance use therefore tends to continue until no more is left or the person becomes stuporous or is told by a partner to stop.
Neurobiological changes explain how addictive disorders develop from patterns and habits of use to powerful internal drives, that become less and less responsive to attempts of control.
From this recently acquired scientific knowledge, we can now interpret addictions as the serious disorders they are. Modern scientific understanding is increasingly in accord with what those with addictive disorders actually experience. It is curious that it has taken a hundred years of scientific endeavor to bring professional views more in alignment with those of people who have actually experienced addiction for themselves and know how powerful and destructive a disorder it can be.
“I have absolutely no pleasure in the stimulants in which I sometimes so madly indulge.
It has not been in the pursuit of pleasure that I have periled life and reputation and reason. It has been the desperate attempt to escape from torturing memories, from a sense of insupportable loneliness and a dread of some strange impending doom.”