Substance Use Disorder: Biological Mechanisms, Clinical Effects and Neuroadaptations

Substance use disorder is characterized by a psychological dependence on a substance or a drug that is beyond voluntary control and that can cause serious harm to the individual when used repetitively. The use of drugs, including alcohol, opiates and psychostimulants, is a wide spread behavior in human societies that pose massive public health costs. This paper aims at explaining the neurobiology of drug addiction and investigating the effects of substances such as psychostimulants, opioids, nicotine and alcohol on an individual’s health. Moreover, this paper gives an overview of the neurotransmitters and brains structures that are altered following the excessive use of drugs, and illustrates some of the neurobiological changes that occur during drug addiction. At the molecular level, drug abuse induces functional and morphological changes of specific brain structures, which generally lead to adverse consequences such as drug relapse. Although previous studies have significantly improved our understanding of the neurobiological mechanisms of substance use disorder in humans, more work need to be done to identify potential therapeutic targets and develop new treatment strategies.