Defining Sex AddictionIn the strictest sense, addiction occurs in response to a substance, with a pattern of tolerance and withdrawal. Although some form of desensitization and withdrawal have been observed in relation to excess sexual behaviors, many people consider this more of a compulsion than an addiction. Many refer to an adherence to a certain behavior as more of a habit than an addiction, although some see no difference. This has caused some fierce debate not only as to how to define it, but also how to treat it.
There are those who absolutely cannot control their hypersexual behavior. Examples of these would be the hypersexuality that is often seen in a severe manic episode, Kluver-Bucy syndrome (which occurs when both temporal lobes of the brain are damaged by trauma or disease), methamphetamine use, and some other neurological conditions or certain kinds of brain trauma. All of these are accompanied by distinct and noticeable changes in personality and activity level. Treatment in any of these cases would require ongoing treatment with a psychiatrist or a neurologist, and medications are used. As you can see, these are not typically the types of "sex addiction" you read about or see on the news.
Excluding people such as those mentioned above, I tend to be of the camp that understands excess sexual behavior as a compulsion for some and an impulsive behavior for others. By compulsion, I mean that the person feels driven to act out this behavior and feels quite anxious or uncomfortable if they cannot. Think of the person who cannot leave the house because they have to continue to check to make sure the stove is off. If viewed this way, one could start to make a distinction between some excessive, compulsive sexual behaviors, and other sexual behaviors. Still others tends to use sex in an impulsive way, not feeling compelled to act, but wanting to do it anyway.
Another difficulty with the use of the term "sex addiction" is that it is a bucket term that can include anything from excess masturbation, to excess time viewing pornography, to promiscuous sexual activity with one or more partners, or any combination of the above. The reason why someone might engage in impulsive or compulsive sexual activity can be varied too. Some people act out this way because it is the only way they feel comfortable with closeness to another person, some have low self-esteem and are trying to get approval, others find that they get a much quicker arousal response from intense stimuli or interactions and find this easier than the lower intensity of a long-term relationship.
You can see with all this variation, treatment is not often simple and usually requires interventions on both a behavioral level and a psychological level. For this reason, there are many who believe that simple 12-step programs or quick "rehabs" are an over-simplified approach to a multi-factorial problem. The other issue is that sex is a normal part of our lives for which we have natural cravings and direct physical response. Because of this, those that understand the complexity of treating eating disorders have a much better appreciation for the complexity of excessive sexual behaviors.