Everyone is writing about Tiger Woods, and I am not at all inclined to join in – but I suppose since it relates to sexual addiction, I will. The casual use of the concept of 'sexual addiction' in relation to his recent diagnosis and treatment may warrant some debate among psychiatrists. What is sex addiction all about?

I understand hypersexuality, and I understand addiction, but I am not sure I understand sex addiction.

As a sexologist, I would first want to apply here the concept of a hierarchy of diagnoses. So a high amount of sexual activity could certainly occur with many conditions, and the concept of a sex addiction, if valid, would have to be the last thing one would diagnose – a diagnosis of exclusion since it could happen with so many other things.

First on everyone's list of causes of high sexual activity, I would think, should be mania, or bipolar disorder. Next, or right with it, would be obsessive compulsive disorder (OCD), with sexual content; this is quite common. Then perhaps PTSD with sexual trauma (with later hypersexuality in some people), substance abuse (e.g., amphetamine, steroid, or testosterone abuse), and frontal lobe syndrome.

Some depressed individuals also appear to engage in sexual activity, not because of aroused libido, but out of a wish to come out of their isolation and engage with others, even if only physically.

Sexual addiction, as a concept, though, would seem to represent nothing but sex: no mania, nor PTSD, nor substance use, nor other causes. Addiction, as a concept, implies an intense feeling of acute pleasure, followed by a wish to repeat, and, often, tolerance and withdrawal. In this context, tolerance would mean that the more one experienced sex, the less pleasurable it would be; and withdrawal would mean that when abstinence occurred, one experienced painful psychological or physical symptoms (perhaps depression and anxiety).

Addiction also implies something that perhaps begins as an experiment, later becomes a habit, and then becomes autonomous. Neurobiologically, addictions tend to involve, we think, activation of the dopaminergic pleasure centres of the brain. Can lots of sex take on this pattern?

It seems difficult to me to distinguish Obsessive Compulsive Disorder from so-called sexual addiction; perhaps the main difference would be that the individual is bothered by his behaviour in one case (OCD) and not the other (addiction); yet this single minor subjective difference would seem to be a small feature upon which to base this diagnosis.

There appear to be many cases of OCD without insight, that is, OCD in which the patient is not much bothered by his or her symptoms. OCD is not, traditional teaching notwithstanding, uniformly characterised by presence of insight.

One reputable website defines sexual addiction as "a progressive intimacy disorder characterised by compulsive sexual thoughts and acts". DSM's definition, under paraphilias, as sexual disorders NOS includes the following ideas: "compulsive searching for multiple partners, compulsive fixation on an unattainable partner, compulsive masturbation, compulsive love relationships and compulsive sexuality in a relationship." This kind of definition seems quite hard to distinguish from OCD with sexual content.

The difference in terminology is important; the idea of sexual addiction would seem to imply analogies to substance abuse: 12 step programs, a limited role for medications, Malibu resorts. The OCD concept would put medications central to the treatment, and make the problem more biological in origin and pathogenesis, rather than simply habit gone awry.

Where we are uncertain, I would prefer the term sexual paraphilia, so as to remain neutral as to the addiction versus OCD dichotomy. Dr Martin Kafka, a specialist in paraphilias, with whom I have shared patients and whose expertise is large, recently suggested a new DSM category of "Hypersexual disorder", which presumes carefully first ruling out other conditions like OCD and bipolar disorder hierarchically. Though I know he practices this way, I fear that the public at large, and the average clinician, will be too democratic, and too little hierarchical, and forget that such a diagnosis, though perhaps not useless, is one of exclusion, and last resort.

If individuals like Tiger Woods have a variety of OCD, it could be that enough serotonergic antidepressant would knock out their libido or their OCD, or both, to keep them from ruining their lives. But 12 step programs might be tenuous.

I don't know the right answer, but it seems to me that this is yet another part of psychiatry where the lapidary use of popular phrases hardly clarifies.