The basis for addiction
There is a growing viewpoint that drug addiction is a form of dysfunctional learning. Drugs of abuse take over the neurological circuitry involved in motivation and reward. This leads to aberrant learning. Because of this, drug-associated cues can trigger a desire to use, as well as unconscious or compulsive drug-seeking behavior, with the sense that voluntary control over drug use is lost.
The stages of problematic use could be defined as preoccupation/anticipation, binge/intoxication, and withdrawal/negative effect. As drugs activate neuronal pathways in the brain, they get 'laid down' stronger and stronger with each use. These pathways also activate faster with each use. The quicker the effect, or 'high', the stronger the dysfunctional learning. In addition, objects, people, or places also seem to to be strongly associated with the drug experience, making them 'triggers' to 'cravings' and increase the chances of further use. Those that favor the biological models of addiction see these neuro-chemical changes in the brain as evidence that addiction is a disease, though research has shown that this learned behavior can be unlearned. Unfortunately, substance abuse also inhibits further learning, meaning continued use makes unlearning more challenging.
Abused drugs can also modulate long-term potentiation (LTP) and long-term depression (LTD) in neuronal circuits associated with the addiction process, suggesting a way for the behavioral consequences of drug-taking to become reinforced by learning mechanisms. Effectively assessing where an individual is in addiction and tailoring treatment to this would make treatment outcomes more effective. This may be why there has been no outstanding results in terms of treatments for addiction with the most significant factor in recovery being the user therapist relationship In addition to determining where someone is in terms of addiction, indications as to where they are in their current cycle of use: Crash, withdrawal or extinction would also inform appropriate treatment interventions.
Animal studies have shown that drug availability (over and above the actual effects of the substance) are associated with stimuli exposure to objects associated with use; these trigger the release of adrenaline (which causes "fight or flight" response). The excitation can be perceived as a 'need' to use.
Glutamate, Dopamine, and Serotonin have long been associated with highly dependent addictions are well established as key to the compulsive behavior related to cocaine and amphetamine use,Norepinephrine, GABA& NMDA are also very important in terms of learning and 'Addiction' With GABA seeming strong in terms of alcohol abuse and the corresponding crash.(For another view of drug addiction, see Rat Park.)'