It's official. Sex addiction is a mental-health disorder in the mind of the World Health Organization (WHO). Some experts beg to disagree, however.

Be that as it may, WHO has added sex addiction -- or the inability of a man or woman to control his or her intense sexual urges be it sex or masturbation -- to its International Classification of Diseases (ICD) list. ICD is the international standard diagnostic tool for epidemiology, health management, and clinical diagnoses.

The clinical term for sexual addiction is "compulsive sexual behavior disorder" (CSBD).

ICD describes CSBD as a "persistent pattern of failure to control intense, repetitive sexual impulses or urges resulting in a repetitive sexual behavior." The hallmark of sex addiction is sex becoming the central focus of a sex addict's life to the extent this person neglects his health and personal hygiene. His personal interests and responsibilities also fall by the wayside.

To be called sex addiction, this behavior should be have been going on for six months or more. The person should experience substantial distress as a result of his or her addiction before being diagnosed, according to WHO.

"Adding this to the WHO list is an excellent step for patients as it allows them to recognize that they are suffering with a problem. It takes it out of the shadows and they are able to seek help for it," said Dr. Valerie Voon from the Royal College of Psychiatrists.

She said sex addiction is a behavior that tends to be hidden because it's shameful. As a result, sex addicts don't often come forward and talk to their doctors about it.

She estimated sex addition affects from three to six percent of adults in the United States and from two to four percent in the United Kingdom.

British comedian Russell Brand has been to rehab for sex addiction. He argues that craving sex gives him "a breathing space when you're outside of yourself and your own head."

Hollywood actress Lindsay Lohan is another well-known sex addict. She herself as "not a crazy (sex) addict" but said she enjoys being in different relationships. She became notorious for revealing a list of male celebrities she had sex with, ranking them from one to 10 or from best to worst in sex.