Compulsive emailing and text messaging could soon become classified an official brain illness.
An editorial in the past month's issue of the American Journal of Psychiatry says Internet addiction (including "excessive gaming, sexual preoccupations and email/text messaging") is a common compulsive-impulsive disorder that should be added to psychiatry's official guidebook of mental disorders.
Like other addicts, users experience cravings, urges, withdrawal and tolerance, requiring more and better equipment and software, or more and more hours online, according to Jerald Block, a psychiatrist at the Oregon Health and Science University in Portland.
Block says people can lose all track of time or neglect "basic drives," like eating or sleeping.
Block says about 86 per cent of Internet addicts have some other form of mental illness, but that unless a therapist is looking for it, Internet addiction is likely to be missed.
He argues the phenomenon warrants being included in the Diagnostic and Statistical Manual of Mental Disorders, psychiatry's official dictionary of mental illnesses. The next edition, DSM-V, is due out in 2012. A draft is expected to be available for public comment next year.
But some say the research into Internet addiction is in its infancy and wonder how doctors decide when computer use crosses the line from the normal, to pathological.
British psychiatrists, reporting last year in the journal Advances in Psychiatric Treatment, say a "significant minority" - some estimate between five and 10 per cent of online users - are addicted to the Internet, and that while early research suggests most are highly educated, highly introverted males, more recent studies suggest the bulk of the problem is occurring among middle-aged women on home computers.
Some use computers like they would drugs or alcohol as a way to escape reality, the researchers say. Addicts may be addicted to everything from the sheer act of typing, to chat rooms, online shopping or three-dimensional, multiplayer games users have described as "heroinware."
According to addiction therapist John Macdonald, of the Centre for Addiction and Mental Health in Toronto, computer use becomes problematic when the behaviour starts affecting people's lives.