In the United States, 21.6 million individuals older than 12 are diagnosed with abuse or dependence to drugs and/or alcohol each year [1]. Consequently, direct and indirect costs to society stemming from addiction total more than $700 billion annually in the United States alone [1]. Addiction to drugs and alcohol has long been recognized as a mental health disorder, appearing in some form in the Diagnostic and Statistical Manual of Mental Disorders (DSM) since its inception in 1952 [2]. However, only recently have non-drug addictions (e.g., food and behavioral addictions) begun to gain increased acceptance as potentially classifiable addictions, as emphasized by the American Psychiatric Association’s (APA) reclassification of pathological gambling into the Substance-Related and Addictive Disorders category in the recent DSM-5 [3]. Only a minority of individuals who drink alcohol, smoke, or use drugs develop pathological use. The same can be said of individuals who eat, gamble, play online video games, or engage in other behaviors that might become addictive. Even individuals who engage in heavy drinking or who are obese may not meet suggested criteria for pathological alcohol use or eating behavior. Furthermore, in lesser amounts, using alcohol, using drugs, or engaging in behaviors with addiction-like potential may provide benefits. Thus, a spectrum of use exists, begging the question of where to draw the line between heavy use and addictive use. Clinical definitions distinguish heavy from pathological use by a continuation of use despite adverse consequences and a presence of distress, but in practice, this distinction is often difficult to make. In exploring substances and behaviors with addictive potential, it is critical to obtain a multifaceted, unbiased understanding of how the substances and behaviors both benefit and harm individuals and society in order to best discover policies and treatments to address addiction. In this issue of the Yale Journal of Biology and Medicine, the editors present articles on a variety of topics related to addiction in order to provide an informative, well-rounded depiction of drug and alcohol use, maladaptive behaviors, and potential policies and treatments related to addiction. The editors have selected articles that highlight areas within addiction that are emerging in importance. Original research presented by Serafini and Stewart demonstrates the importance of perceptions of sibling’s alcohol use on the likelihood of drinking alcohol in young adults. Rutherford and colleagues also present original research, investigating the differences in brain structure between substance-using and non-substance-using mothers and how maternal substance use relates to general motivation. Often people have the mindset that any drug prescribed by a doctor in a medical setting is safe from addiction and abuse, but clinicians know otherwise. In this issue, Tetrault and Butner provide an overview of the increasing rates of non-medical prescription opioid use and the accompanying growing dangers of addiction and overdose. Hawk and colleagues review strategies aimed at reducing fatalities from opioid overdose, which are becoming more common in the United States from increased prescription opioid use. Weaver also describes misuse and abuse of prescription sedatives such as benzodiazepines. Additionally, drugs such as marijuana have been demonstrated to have potential medical uses despite being illegal to prescribe by physicians in most U.S. states. Hall reviews the policy changes that have been made with the increased adoption of medical marijuana in the United States. Sun and colleagues review the effectiveness and safety of the use of marijuana for treatment of glaucoma. Understanding the benefits of drugs of abuse is important for policy and prevention targeted toward reducing addiction. Smoking tobacco and obesity are the two leading causes of preventable death in the United States [4]. Annamalai reviews the importance of encouraging patients with serious mental illness to attempt smoking cessation, an important topic since the rates of smoking among people with serious mental illness remain much higher than the general population. Wickham reviews the biology of how menthol interacts with nicotine, which is an imperative line of research to study given the growing market for flavored electronic cigarettes. Rupprecht reviews the intersection and interrelation of the two health hazards of obesity and smoking. Additionally, Meule chronicles the history of food addiction research. An enhanced understanding of non-drug addictions is emerging in importance as the APA promotes researching more behavioral addictions for inclusion in the next edition of the DSM. In this vein, Szabo details the importance of coming to a common consensus about what constitutes a behavioral addiction as he discusses the particular case of exercise addiction. Xu and colleagues review the research on video game addiction and detail the associated risk of addiction when developing video games to treat amblyopia. Voss and colleagues describe a case report of pornography use-associated Internet Gaming Disorder, a behavioral addiction garnering increasing attention. Treatment development is another area of active investigation in the field of addiction, and several relevant articles are contained in this issue. Xu and colleagues describe a novel technique using transcranial direct current stimulation (tDCS) to increase activity in both sides of the prefrontal cortex, and the authors discuss the potential for treating addiction using tDCS intervention. Melemis offers his perspective on maintaining recovery from addiction using five rules to avoid relapse. Heshmat describes recovery from addiction from a behavioral economics perspective, offering his insight into how best to achieve abstinence. Additionally, Robertson-Boersma and colleagues discuss the potential for peer intervention to reduce binge alcohol drinking in college students. It is crucial for society to continue to increase its understanding of addiction to drugs, alcohol, and behaviors in order to establish improved behavioral and pharmacological treatments for addiction. Additionally, continued unbiased discussion about addiction will allow society to develop and implement effective public policy that balances both the detrimental and beneficial effects of drugs, alcohol, and addictive behaviors. Lastly, additional research into non-drug addictions is essential in order that a valid and reliable diagnostic system can be created to better identify and treat addictions to food, exercise, video games, etc. in a clinical setting. The articles presented in this issue aim to advance society one step further in its knowledge and understanding of addiction.
