The first people to come up with the term Reward deficiency syndrome were Blum K, Sheridan PJ, Wood RC, Braverman ER, Chen TJ, Cull JG and Comings DE in a research titled; The D2 dopamine receptor gene as a determinant of reward deficiency syndrome in 1996. This term refers to an insufficiency of usual feelings of satisfaction. Reward deficiency syndrome results from a dysfunction in the brain reward system which is a complex interaction among neurotransmitters primarily dopaminergic and opiodergic neurotransmitters. Those who have a family history of alcohol and other drugs addictions may be born with a deficiency in the ability to produce or utilize these neurotransmitters which are known to play crucial in etiology of addiction to substances. This problem can also be caused by corruption of brain reward system that may be caused by exposure to long periods of stress or use of alcohol and other substance for a long time. When the neurotransmitters are low or are blocked from reaching the intended brain receptors, individuals often feel discomfort or pain. Behaviors resulting from a failure of the system that normally confers satisfaction include drug and alcohol abuse, overeating, heavy cigarette smoking, gambling, and hyperactivity. These problems have been linked to genetic defects especially to dysfunction of the dopamine receptors.
A dysfunction in the dopamine receptors obviously leads to myriads of health complications since it is the brain neurotransmitter that controls feelings of well-being and is mostly targeted by drugs of abuse. However powerful dopamine doesn’t work alone, it interacts with other neurotransmitters like serotonin and other neurotransmitters to control moods and cravings. When these neurotransmitters bind on the neural receptors, they trigger a reaction in the reward system, therefore any interference with this coordination will result in abnormal behavior in Reward deficiency syndrome, including addictions, impulsivity, and excessive risk taking. This is the reason why people who have a defect in the DRD2 dopamine receptor gene lack a sufficient number of dopamine receptors in their brains to produce the brain reward cascade. In turn, this leads to Reward deficiency syndrome, including abnormal cravings and resultant strange conduct.
The reward circuitry consists of an in-series circuit linking the ventral tegmental area, nucleus accumbens and ventral pallidum via the medial forebrain bundle. In the past the reward circuitry was believed to encode only the set point of hedonic tone but have since been found to be functionally far more complex, also encoding attention, expectancy of reward, disconfirmation of reward expectancy, and incentive motivation. Here have been speculations that hedonic dysregulation within the reward circuits may lead to addiction. A second-stage dopaminergic component in this reward circuitry is the crucial addictive-drug-sensitive component. All drugs that are addictive are known to enhance the dopaminergic reward synaptic function in the nucleus accumbens. as for most of addictive drugs like cocaine the tolerance to the euphoric effects will develop after a long term use after which a post use dysphoria then comes to dominate reward circuit hedonic tone, and addicts no longer use drugs to get high, but simply to get back to normal. Reward deficiency syndrome as seen here may make an addict chained to the drug of use since the addict will need to feel normal but that will not possible since the dopamine receptors and parts of the reward circuit will have been affected adversely and so the drug use will be continued as a result of Reward deficiency syndrome and not for euphoric purposes.
It is also important to note that the brain circuits that mediates pleasurable effects of addictive drugs are anatomically, neurophysiologically, and neurochemically different from those mediating physical dependence, and from those mediating craving and relapse. Apart from Reward deficiency syndrome other factors that also come to play in addiction include gene variations that may increase vulnerability to drug addiction. Environmental factors also have an input for example prolonged stress and social defeat may also increase a person’s vulnerability to drug addiction as they alter the brain reward system. However dopaminergic dysfunction within the reward circuitry is the biggest contribution to addiction-prone personality effects.
Reward deficiency syndrome has influence in drug addiction and therefore any drug addiction treatment must incorporate strategies to treat Reward deficiency syndrome in order to avoid reoccurrence of the addiction after a hard won fight. In fact when the problem in the reward circuitry isn’t addressed then treatment of addiction will have very narrow chances of success. To help in this pursuit, treatment of cocaine addiction should have in part a dopamine agonist agonistic therapy to heal the dopaminergic system.
When an agonist therapy is to be used, it’s crucial to note that the baseline amount of dopamine receptors has predictability as to differential clinical outcomes in reward deficiency syndrome. In a study of 10 subjects with an allele on the Taq1A DRD2 gene, which is associated with reduced dopamine receptor concentration and decreased neural responses to rewards (A1+ subjects). The 10 subjects were scanned twice, once on placebo and once on cabergoline which is D2 receptor agonist. Consistent with an inverted-U relationship between the DRD2 polymorphism and drug effects, cabergoline increased neural reward responses in the medial orbitofrontal cortex, cingulate cortex, and striatum for A1+ subjects, but decreased reward responses in these regions for A1− subjects. Drug addiction treatment should therefore put in place measures to ensure that reward deficiency syndrome is treated. Dr. Dalal Akoury of AWAREmed Health and Wellness Center has dedicated her life to helping patients restore their lives by use of integrative medicine. She also holds many conferences in which she offers training on how integrative medicine can be used to fight addiction among other conditions. Call her on (843) 213-1480 for help.