The new definition resulted from an intensive, four‐year process with more than 80 experts actively working on it, including top addiction authorities, addiction medicine clinicians and leading neuroscience researchers from across the country. ... Two decades of advancements in neurosciences convinced ASAM that addiction needed to be redefined by what's going on in the brain.

It's likely ASAM acted, in part, because the psychiatrists who are revising the DSM (the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders) have been dragging their feet in bringing the upcoming DSM-5 into alignment with advances in behavioral addiction research. Traditionally, the DSM offers diagnoses based not on underlying disease, but on lists of behaviors. Since DSM authors can't agree on a list of sexual behaviors that constitute "Hypersexuality Disorder" (which addresses compulsive porn use), they are hamstrung. In fact, they may banish the disorder to the appendix—right as Internet porn use among adolescent boys is becoming nearly universal.

In contrast, the ASAM definition, "looks at the role of the brain in the etiology of addiction—what is happening with brain functioning and specific brain circuitry that can explain the outward behaviors seen in addiction." It is an acknowledgement that a sexual behavior (e.g., viewing Internet porn daily) may be evidence of pathology in one person's brain without reflecting pathology in another's.

Research shows that both behavioral and chemical addictions entail the same major alterations in brain anatomy and physiology. An ASAM spokesman explained:

The new definition leaves no doubt that all addictions—whether to alcohol, heroin or sex, say—are fundamentally the same. Dr. Raju Haleja, former president of the Canadian Society for Addiction Medicine and the chair of the ASAM committee that crafted the new definition, told The Fix, "We are looking at addiction as one disease, as opposed to those who see them as separate diseases. Addiction is addiction. It doesn't matter what cranks your brain in that direction, once it has changed direction, you're vulnerable to all addiction." ...Sex or gambling or food addiction [are] every bit as medically valid as addiction to alcohol or heroin or crystal meth.

Here is a brief summary of ASAM's major points:

1. Addiction reflects the same brain changes whether it arises in response to chemicals or behaviors.
2. Addiction is a primary illness. It's not necessarily caused by mental health issues such as mood or personality disorders. This puts to rest the popular notion that addictive behaviors are always a form of "self-medication" to ease other disorders.
3. Both behavioral and substance addictions cause the same major changes in the same neural circuitry: Hypofrontality, sensitization, and desensitization.
4. Engagement in chronic "addictive behaviors" indicates the above brain changes have occurred. Addictive behaviors then become unconscious and habitual.
5. The new definition eradicates the old "addiction vs. compulsion" distinction, which was often used to deny the existence of behavioral addictions, including Internet porn addiction.

Unlike the brains of gambling, food, videogame addicts, the brains of sex/porn addicts have not yet been scanned. Yet the brain mechanics of behavioral addiction are already so well defined, that experts can say with confidence that sexual behaviors are also potentially addictive. In other words, it's not the form or quantity of a stimulus, but rather the resulting brain changes, which matter. These excerpts from ASAM's FAQs explain the science common to all addiction:

QUESTION: What's different about this new definition?

ANSWER: The focus in the past has been generally on substances associated with addiction, such as alcohol, heroin, marijuana, or cocaine. This new definition makes clear that addiction is not about drugs, it's about brains. It is not the substances a person uses that make them an addict; it is not even the quantity or frequency of use. Addiction is about what happens in a person's brain when they are exposed to rewarding substances or rewarding behaviors, and it is more about reward circuitry in the brain and related brain structures than it is about the external chemicals or behavior that "turn on" that reward circuitry.(Emphasis added.)

Addicts share common brain changes, which show up in behavior as unsuccessful attempts to control use, cravings during abstinence periods, and withdrawal symptoms. To date, the underlying brain changes seen in all addicts (desensitization, sensitization, and hypofrontality) have already been observed in the brains of compulsive gamblers, overeaters, videogamers. It's likely they are present in today's compulsive porn users as well. If it walks, talks and acts like a duck, it's a duck.

Another implication of ASAM's statement is that one cannot define "porn addiction" by time spent viewing or genres watched. Porn addiction exists only if the relevant brain changes have occurred in the viewer. Since brain scans are impractical, ASAM has created a 5-part assessment to help people figure out if their brains have changed. This is similar to assessing diabetes markers in patients complaining of telltale symptoms.

These next two questions from ASAM address sex and food addictions specifically:

QUESTION: This new definition of addiction refers to addiction involving gambling, food, and sexual behaviors. Does ASAM really believe that food and sex are addicting?

ANSWER: Addiction to gambling has been well described in the scientific literature for several decades. In fact, the latest edition of the DSM (DSM-5) will list gambling disorder in the same section with substance use disorders.

The new ASAM definition makes a departure from equating addiction with just substance dependence, by describing how addiction is also related to behaviors that are rewarding. This the first time that ASAM has taken an official position that addiction is not solely "substance dependence."