Dr Himanshu Tyagi said sites such as Facebook and MySpace may be harmful.
He told the Royal College of Psychiatrists annual meeting people with active online identities might place less value on their real lives.
And the West London Mental Health NHS Trust expert added this could raise the risk of impulsive acts or even suicide.
They reinforced this point with an extended quote, presumably from the paper that Tyagi delivered:
It's a world where everything moves fast and changes all the time, where relationships are quickly disposed at the click of a mouse, where you can delete your profile if you don't like it, and swap an unacceptable identity in the blink of an eye for one that is more acceptable.
People used to the quick pace of online social networking may soon find the real world boring and unstimulating.
It may be possible that young people who have no experience of a world without online societies put less value on their real world identities and can therefore be at risk in their real lives, perhaps more vulnerable to impulsive behaviour or even suicide.
I have long been interested in such matters as the distortion of our sense of reality by social [sic] software and the pathological implications of such distortions; so I took great satisfaction in finding and expert psychiatrist framing this all in a more clinical perspective (even if my own recent focus on the reality factor in social networking has had more to do with adult political behavior). A rebuttal to Tyagi's paper was delivered by psychologist Graham Jones, quoted by the BBC as follows:
For every new generation, the experience they have of the world is a different one.
When the printing press was first invented, I am sure there were crowds of people saying it was a bad thing.
In my experience, the people who tend to be most active on sites such as Facebook or Bebo are those who are most socially active anyway - it is just an extension of what they are already doing.
As is often the case, this is one of those disputes that will probably eventually come down to who has the better data; and, regrettably, the presentation and analysis of specific data sources is beyond the scope of the BBC! The best we can hope is that they will report follow-up findings, even when those findings are not connected to a prestigious convention!