This report describes the current understanding of the neuroscience of psychoactive substance use and dependence.1 Neuroscience is concerned with all of the functions of the nervous system, particularly the brain. Psychoactive substances have the ability to change consciousness, mood, and thoughts. This report draws on the explosive growth in knowledge in neuroscience in recent decades, which has transformed our understanding of the actions of psychoactive substances, and contributed new insights into why many people use psychoactive substances, and why some use them to the extent of causing themselves harm or of becoming dependent.
1 [The term "substance use" is employed in this document to refer to any form of self-administration of a psychoactive substance. It is used instead of the term "substance abuse" as a broader term encompassing all levels of substance involvement, including occasional and prolonged consumption of a substance.]
The need for this report comes from these advances in neuroscience research, which have shown that substance dependence is a chronic, relapsing disorder with a biological and genetic basis, and is not simply due to lack of will or desire to quit. Effective treatments and interventions for substance dependence do exist, and involve both pharmacological and behavioural interventions. The stigma associated with substance use and dependence can prevent individuals from seeking treatment, and can prevent adequate policies regarding prevention and treatment to be implemented. A WHO study of attitudes to 18 disabilities in 14 countries found that ‘‘substance addiction’’ ranked at or near the top in terms of social disapproval or stigma, and that ‘‘alcoholism’’ ranked not far behind in most of the societies studied (1). Neuroscience-based knowledge of substance dependence affords an opportunity to clarify misunderstandings, and to eliminate incorrect and damaging stereotypes.
This report covers information on the global burden of substance use and dependence, including global statistics, individual and societal consequences of the acute and chronic use of psychoactive substances, and illustrates the pervasive effects of substance dependence throughout the world. The effects of psychoactive substances on the brain, and how they promote the development of dependence is discussed, along with the genetic and environmental factors that may predispose or protect individuals from developing substance dependence. Many treatments, both biological and psychological, are available and are discussed, along with the ethical implications of such treatments. This report concludes with key recommendations and implications of neuroscientific knowledge of substance dependence for public health policy.
Global use of psychoactive substances and burden to health
Global use of alcohol, tobacco, and other controlled substances is growing rapidly, and contributing significantly to the global burden of disease.