Addiction encompasses a wide variety of maladaptive characteristics of drugs usage or other behaviors that result in clinically substantial damage or discomfort. Addiction involves alcoholism, tobacco addiction, marijuana and cocaine use disorders, and also non-substance–related behaviors. These severe yet frequent mental diseases are major causes of morbidity and death across the globe. It is a behavioral attribute being researched for its hereditary origins and inheritance patterns. The heredity of this condition was discovered when completing a genealogy study on a significant number of afflicted people. It was discovered that the disorder might be passed down through generations. However, efforts to relate specific genes to the origin of this condition and track their inheritance are far from complete.

Several families, adoption, and twin studies have shown that hereditary variables play a considerable role in individual variability in addiction. According to twin research findings, heritable variables account for 40–80 percent of the variance in nicotine dependency liability, whereas alcohol addiction accounts for 45–70 percent of the variation. Similarly, a recent meta-analysis of twin studies found that marijuana addiction had 52–60% of heritability. Heritability estimates for cocaine use problems vary from 44 to 81 percent, with women having lower rates. Other investigations on opioid addiction showed some evidence for unique genetic characteristics. According to the studies, addiction susceptibility in several co-process. Addiction starts only with initial phases of usage, proceeded by progression to persistent use that becomes troublesome and leads to dependence. Initial stages are less genetically determined and heavily impacted by family environmental variables, but later phases, like problematic use and dependency, are largely affected by hereditary factors.