Short answers, pulled from the story.
Modern definitions describe addiction as a persistent and intense urge to use drugs or engage in behaviors that produce immediate psychological rewards. These urges persist despite substantial harm and negative consequences.
DeltaFosB serves as a critical gene transcription factor in the development of virtually all forms of behavioral and drug addictions. Its overexpression in D1-type medium spiny neurons within the nucleus accumbens is necessary for many neural adaptations seen in drug addiction.
Genetic factors account for 40 to 60% of the risk factors for alcoholism according to established data. Twin studies provide some of the highest-quality evidence showing that if one twin is affected by addiction, the other is likely to be as well.
The fifth edition of the Diagnostic and Statistical Manual uses the term substance use disorder to refer to a spectrum of drug use-related disorders. This manual eliminates terms like abuse and dependence, instead using specifiers of mild, moderate, and severe to indicate the extent of disordered use.
In Asia, internet addiction disorder prevalence reaches 5% according to the Internet Addiction Test and 21% according to the Revised Chen Internet Addiction Scale.
Those using these drugs showed a 40% lower risk of opioid overdose and a 50% lower risk of alcohol intoxication compared to non-users. Researchers analyzed nearly nine years of health records from 1.3 million individuals across 136 U.S. hospitals.