Theo did not seem like the type to become addicted to gambling. He was a literary star who had published his first novel at age 24 to great success. While traveling through Europe, he began visiting elegant casinos, at first dabbling in table games like roulette. With time, though, this pleasant diversion became a compulsion, and he lost nearly all his money in just a few years. He continued to produce critically acclaimed books—at one point churning out a new novel in less than a month to settle urgent debts—but he struggled to stay afloat, and his wife soon had to sell her jewelry. Remarkably, aside from the gambling, his life seemed fine. His writing was respected, and his family life was satisfying. He was simply hooked.

“Theo” is actually Fyodor Dostoyevsky, the prototypical gambling addict. Despite profound insight into the human condition, Dostoyevsky struggled with gambling for many years and was almost financially ruined several times. His semiautobiographical novel The Gambler—written to cover his debts, published in 1867—described compulsive gambling so well that 20th-century psychiatrists studied it as a model for the concept of gambling addiction.

Well over a century ago people already realized that an individual could have what is today called a behavioral addiction: an overwhelming, repetitive and harmful pattern of behaviors apart from drug or alcohol abuse. Now, 150 years after Dostoyevsky first walked into the casinos of Romantic-era Europe, addictions to sex, eating, video games and other behaviors are getting serious recognition in some quarters of medicine and among the public. Casualties of behavioral addictions are appearing in the news: not just gamblers throwing their life savings away but also porn addicts masturbating to iPhones on the freeway and even babies left to die by parents engrossed in video games. Doubters, however, argue that slapping the addiction label on these habits inappropriately excuses bad behavior.

Are these behaviors mental disorders? Many people are striving to limit their screen time or watch their diets, but does that mean that Internet and food addiction epidemics are upon us? Proponents argue, neuroscience evidence in hand, that behavioral addictions are brain disorders, but critics question those interpretations and protest that we are unnecessarily medicalizing everyday suffering.

This leaves psychiatrists like me in a difficult position. In my practice in New York City, I received more inquiries in the past year from people seeking help for Internet addiction than for cocaine and heroin addiction combined. It is hard to deny that for some of them, behavioral addictions are real—these individuals are truly overwhelmed by repetitive, harmful behaviors. Their schooling, marriage or job is in danger because of their uncontrolled actions. They sincerely want to stop, but they feel powerless. A mental disorder is defined simply as a dysfunctional thought process or behavior that causes harm. In my view, some behavioral addictions clearly meet that description—there is a reason we have had this intuition since the time of Dostoyevsky.

Yet many people rush to diagnose themselves with behavioral addictions, not recognizing the underlying depression or anxiety driving their problems. Treatment for them may have different considerations, and research is just starting to offer clues about how to help these different types of addictions. After all, that is the goal of all the questions and debates—how can we best help people who are suffering?

As I set out to understand this phenomenon, I found that even the experts within the field are divided—and that includes those who support the idea of behavioral addiction. But along the way I also caught glimpses of paths toward a resolution.

Disordered desires

People were making unhealthy choices about sex, eating and money well before Dostoyevsky. Saint Augustine's Confessions, written sometime around the year 400, intricately explores loss of control over sexual impulses. The root of the word “addiction” itself is thought to come from the Latin term for “dedication,” and prior to the 19th century the word was often used to describe behaviors in a positive light, such as being dedicated to public service or “addicted to books.” But a darker view of addiction soon began to emerge.

In the 20th century the temperance movement, the development of psychiatry and the growth of Alcoholics Anonymous all shaped the disease model of addiction: loss of control over drugs and alcohol is a chronic, relapsing, lifelong disorder. As early as 1957, offshoot 12-step programs such as Gamblers Anonymous and Overeaters Anonymous applied the addiction model to problems that did not involve drugs or alcohol.

In 1980 “pathological gambling” was added to the Diagnostic and Statistical Manual (DSM), the American Psychiatric Association's official categorization of mental disorders, as a condition deserving further study. In 1990 Isaac Marks, a psychiatric researcher in London, penned a widely cited editorial in the British Journal of Addiction describing “non-chemical” addictions, and since then the idea has received increasing attention from mainstream researchers and clinicians.

In popular culture, behavioral addictions are also getting much more recognition. Movies such as Shame and Don Jon vividly portray sex and pornography addictions. For better or for worse, sex addiction is the go-to excuse for unfaithful celebrities. Residential rehabilitation centers for Internet addiction are booming in China and even starting to appear in the U.S. Additionally, as developed countries grapple with obesity, a food-addiction model is increasingly used to explain some people's uncontrolled eating.

At the same time, however, the academic understanding of addiction is a conceptual minefield. Organized psychiatry has long shied away from even using the word “addiction.” The DSM formerly called it “dependence,” a stand-in term that emphasized the idea of addiction as a chronic, relapsing disease that is markedly different from other unhealthy drug and alcohol use.

That distinction, between “true” addiction and other harmful patterns of drug abuse, has been struck from the latest edition, the DSM-5, published in 2013. The update radically altered the definition of addiction, collapsing both “dependence” and milder forms of “substance abuse” into one condition, “substance use disorder,” with no clear division between mild and extreme cases. That decision was based on data from more than 200,000 research participants, which showed an even continuum from the worst cases down to less severe substance-use problems.

This changing understanding of addiction makes it even more difficult to know how to define behavioral addictions. Is gambling addiction like drug addiction, or is it something else? The evidence base for most behavioral addictions is far less robust than for substance addictions, but research is beginning to fill in the gaps.

Gambling gets its due

Researchers have increasingly used the tools of neuroscience to argue that behavioral addictions are brain-based disorders. For example, as recently as the early 2000s clinicians were not sure how to categorize pathological gambling. Some thought it looked more like obsessive-compulsive disorder than drug or alcohol addiction. From their perspective, pumping quarters into slot machines or repetitively washing one's hands appeared almost the same—irrational, compulsive and almost automatic.

Marc N. Potenza, a gambling researcher at Yale University, published an enlightening study in 2003. Using functional MRI, a method for assessing blood flow in the brain, his team measured the cerebral activity of people with gambling problems as they watched provocative videos in the scanner: the thrill of an unexpected windfall, the clatter of new chips, the flutter of cards. The imaging revealed decreased activity in the ventromedial prefrontal cortex (vmPFC), an area in the middle of the frontal lobes associated with regulating impulses. People with OCD show the opposite result: they have increased vmPFC activation during obsessions, indicating excessive thoughts and preoccupations. These and subsequent imaging findings show that the brain activity of problem gamblers looks similar to that of drug and alcohol addicts.

In 2005 a group of researchers in Hamburg, Germany, used fMRI to discover further similarities between behavioral and substance addictions. They measured responses in the ventral striatum, a deep-brain structure rich in dopamine and associated with sensitivity to rewards. Drug and alcohol addicts have been shown to have both reduced activity in the ventral striatum and altered dopamine levels. This lowered activity is consistent with the idea of a reward deficiency: people with addictions have blunted responses to rewards, driving them to compensate by seeking even more gratification. Sure enough, the gamblers in this study showed less activity in the ventral striatum.

Such findings supported the formal addition of “gambling disorder” to the DSM-5. The only other behavioral addiction to be added was “Internet gaming disorder,” but only in the appendix as a condition for further study. Debates were fierce, however, about behavioral addictions in general, and scientific commonalities between behavioral and substance addictions were the crux of the proponents' argument.

A lot like drugs

Much scientific research on behavioral addictions has focused on comparing and contrasting them with substance dependence. Aside from bolstering their status as disorders, doing so can offer clues as to whether similar treatments might work, if such interventions should be covered by insurance companies, and how society should treat people who suffer from these afflictions.

There has been a plethora of fMRI studies since Potenza's influential gambling studies. His initial findings have been replicated several times, and the brain areas implicated are relatively consistent. Preliminary brain-imaging studies have found some similar results in food, sex and Internet addiction, although the results are not always consistent. Overall the findings are not as well aligned with findings from traditional substance-use disorder research.

Investigation of the neurochemistry of these disorders is also preliminary, but some researchers have found altered neurotransmitter receptor function in people with food and Internet addictions. Studies using positron-emission tomography have shown, for example, lower levels of activity in dopamine-producing regions of the ventral striatum at rest in both obese people and people with Internet addiction. PET studies of compulsive gamblers, however, have shown conflicting results. In food addiction, a growing body of evidence from rodents shows changes in neurotransmitters such as dopamine. So although there are interesting clues from neurochemistry, the jury is still out.

Another clue that behavioral addiction may be quite similar to substance addiction is the fact that some pharmaceutical treatments appear to work for both conditions. For example, naltrexone, a drug that blocks opioid receptors in the brain, has successfully treated alcohol and opioid dependence since the 1990s. More recent evidence shows that it can help with gambling addiction, and some smaller trials hint that it might ease sex addiction.

These confluences suggest that behavioral and substance addictions might have the same underlying causes—as does the fact that large population surveys show that the two types of addiction tend to occur together. Such findings are often comforting to people who wonder why they cannot overcome a repetitive behavior—framing it as a “real” addiction can mitigate shame and speed recovery. For me and other clinicians, the similarities between behavioral addictions and drug addictions help us choose and be confident in our therapeutic strategies.

Yet just as with substance addicts, people who show signs of behavioral problems often have other mental disorders that may be complicating the diagnostic picture. To give them the best treatment, sometimes it is important to look more closely at what underlies their behaviors.

Why me?

Patients with behavioral addictions often ask me whether they are fated to be addicts—whether their battles for control are an intrinsic part of their character. We have known for many years that genetic factors explain up to 50 percent of the risk for developing addictions, including problem gambling. Just recently, genetic studies of other behavioral addictions have found similar results. A 2014 study of more than 800 Chinese twins and a 2015 study of more than 5,000 Dutch twins both found that, statistically, genetic factors explained approximately half the risk of compulsive Internet use. The exact genetic contributions, however, are too complicated to make interpretations based on an individual's genetic makeup.

Other factors can be set in motion before a person's birth, as illustrated by rodent research of food addiction. In one 2010 study, mouse mothers on a high-calorie, high-fat diet transmitted an exaggerated preference for fat to their offspring, as compared with control mice on a normal diet. This preference appeared to be passed down through epigenetic alterations that effect the expression of the genes responsible for dopamine-managing proteins in the brain.

Life experience, early exposure and a host of other environmental factors probably play a role in steering a person toward an addiction—the reality is that only a small percentage of people who engage with potentially addictive substances or behaviors end up hooked, and scientists know very little about why. Unfortunately, brain-imaging studies cannot answer that question. If you could go back in time and put Dostoyevsky in a scanner, he would almost definitely show altered activation in his brain's reward centers, but that would not necessarily tell you that gambling was his fundamental problem. Maybe he was instead driven by existential angst, or the trauma of his Siberian exile, or even his documented case of temporal lobe epilepsy.

Explaining the mechanism is not the same as revealing the cause. From the fMRI studies of brain activation down to the intricate functions of neurotransmitters, the issue of causality is a big sticking point for the interpretation of this research. The basics are clear: the brain has circuits that respond to the feeling of pleasure and the anticipation of reward. In some vulnerable individuals, these circuits adapt in response to extreme repetitions of pleasurable activities. Yet this process speaks only to how, not why; what ultimately drives the behavior remains unexplained.

An unexpected illustration of this mystery comes from the treatment of Parkinson's disease. The illness is treated with drugs that act directly on dopamine receptors, and because the drugs disrupt the reward system, some people with Parkinson's develop compulsive behaviors. For some, eating, sex or gambling becomes addictive. Others abuse the drugs themselves, taking more than prescribed and doctor shopping for extra doses. But plenty of people do not develop any compulsive behaviors, even though they experience the same underlying influence—an introduction of powerful dopamine-acting drugs.

Reducing the anatomy of addiction to the “reward system,” therefore, is too simple. Yet discussions of the reward system dominate the scientific discourse about addictions, in part because it is challenging to integrate all the other dimensions that matter—social, psychological, even philosophical concerns.

Societal costs

When hypersexual disorder was proposed as a new diagnosis, critics in the psychiatric community expressed concern about the social and legal ramifications. Would the disorder be misused in court cases involving sex offenders? Would residential treatment centers pop up to unfairly profit from fad diagnoses, or would the disorder be used as an excuse for sexual predation?

Beyond the concrete risks, there is a popular notion that medicalizing behaviors such as compulsive sex and shopping might cast people in an undeserved sick role. There is some value, the argument goes, in preserving the opprobrium that society usually levels at philanderers and spendthrifts. Negative public perception might actually help keep some people in check, whereas a new diagnosis might inappropriately absolve them of responsibility.

If more behavioral addictions are classified as mental disorders—as they almost surely will be, with proponents continuing to muster neuroscientific evidence—there will be societal consequences. Insurance coverage, disability determinations, or the public's understanding of “mad versus bad”—the stakes are high. On the other hand, restricting the recognition of behavioral addictions could curtail identification of and treatment for people who are truly in pain. As long as a behavioral addiction is causing significant harm in a person's life, I believe it needs to be recognized.

This issue of harm, however, is sometimes missed by researchers, which leads to some odd proposals. For example, French researchers recently suggested “tango addiction.” They claimed to have found that one third of recreational dancers had symptoms of craving and that 20 percent had physical withdrawal symptoms related to the (admittedly captivating) Argentine dance. The problem, as even those researchers admit, is they could not find any good evidence of tango causing real problems in people's lives.

The gray area between clear disorders and unhealthy habits is rightfully controversial. Sometimes when people ask if they should call themselves addicts, I have to reply that I don't know. We are in the midst of clarifying and even redefining what addiction means, with our eye constantly on the end goal—to help the people who are suffering from these plights.

The way forward

A paradigm shift is happening in psychiatry, and many researchers now say that no mental illness fits into a neat diagnostic category. In fact, the National Institute of Mental Health is completely revamping its research program to focus less on lumping together symptoms and more on exploring the specific genetic and neurobiological elements of mental disorders. In this way, behavioral addictions are a case study in one of the trickiest problems in psychiatry: how to characterize disorders that have no definitive brain scan, no blood test and no gold standard. With time, and with more research into the underlying causes of such behaviors, we may be better able to help those who feel helpless and out of control.

One promising area of research suggests that any given type of behavioral addiction—say, Internet gaming disorder—might not be one neat disorder but rather an assortment of different underlying problems that happen to manifest the same way. This idea of subtypes was first articulated in 2000 by Alex Blaszczynski, a psychology professor who studies gambling at the University of Sydney. He and his colleague Lia Nower, a professor of social work at Rutgers University, proposed three subgroups of gambling addiction: behaviorally conditioned gamblers who get in the habit of chasing wins and losses, emotionally vulnerable gamblers who are responding to anxiety or depression, and antisocial gamblers who are dysfunctionally impulsive across the board.

Nower and Blaszczynski recently studied data from more than 500 problem gamblers, drawn from an addiction study of more than 43,000 people, and found three distinct groups that matched their model: one group with milder symptoms, one with more co-occurring psychiatric disorders, and one with severe impulsivity across many areas of life. Also, in studies of online gaming, investigators have found distinct motivations similar to Blaszczynski and Nower's model: a preoccupation with mastery (behavioral conditioning), a compensation for real-life problems, or a response to social anxiety (reactions to emotional problems). Although the evidence is still pending, some researchers believe the subgroup model can also be applied to hypersexual behavior.

The point of all these diagnostic refinements, of course, is to help the sufferers of addiction. Unfortunately, studies of treatments tailored to those subtypes have not yet shown any added benefit. Indeed, researchers in the field of substance-use disorder have argued over possible “typologies” of drug and alcohol addiction for decades, and there is still no clear consensus emerging. Perhaps the current models, which are based only on outwardly observable features of addictions, are incomplete. Diagnosis may have to go beyond the psychological features of addicts and look at their underlying genetics and neurochemistry. For example, in the substance-addiction field, researchers have recently shown that variations in genes for specific neurotransmitter receptors can predict addicts' responses to medications such as naltrexone. Considering how new this work is, the behavioral-addiction field may need time to catch up.

In the meantime, a flexible and holistic approach to treatment is best. People who consider themselves Internet addicts or sex addicts, whose problems are complicated by social anxiety or depression or other issues, need more attention to the emotional component of their behavior, as opposed to those who fit the traditional model of addiction and feel stuck in an automatic cycle of stimulus and response. Research has shown that when people have both substance-use problems and other emotional issues, we get the best results by treating all issues simultaneously.

My own approach is to aim for this inclusive mind-set. We have to assume we do not have all the answers. People cannot simply be reduced to their “hijacked” reward systems, and there is no single, unassailably correct diagnosis of or treatment for addiction. Someday a new wave of research findings may help make finer distinctions more precisely. For now, though, we do the best we can by trying to learn as much about our patients as possible.

There are no easy answers. As the examples of Dostoyevsky and Saint Augustine show us, we humans have been endeavoring for ages to understand why we get stuck in patterns of harmful behaviors and why for some the consequences from losing control are truly severe. As we begin to focus on this problem with real scientific rigor, the right question might not be “Is this real?” but rather “How can we help?”