You go out on a date, and when your friends ask how it went you reply: "Oh, she's psychotic." Or perhaps: "He's delusional."

The justifications for such adjectives being used might be simple.

In the former case, the lady might have asked, just as the main course plates were cleared away, where the gentleman thought the relationship was going. This was after having described the details of her previous 17 relationships.

In the latter case, the gentleman might have talked about himself throughout the meal and offered mathematical details about his mental and physical prowess.

However, when these words are used in a clinical context, they have more precise definitions.

Which is why I have been moved to contemplation on hearing news of research from Israel. It declared that Facebook and its ilk can move the vulnerable (which might mean anyone) in the direction of psychosis and delusion.

Doctor Uri Nitzan of Tel Aviv University's Sackler Faculty of Medicine and the Shalvata Mental Health Care Center decided, along with his colleagues, to look at his own patients in the context of their online relationships.

He wondered whether psychopathologies might be related to activities on Facebook and in chat rooms.

As the Daily Mail reports, the researchers discovered that the patients -- who all were experiencing "loneliness or vulnerability due to the loss of or separation from a loved one" -- suffered from further negative effects the more they "socialized" online.

The Mail quoted Dr. Nitzan as saying: "In each case, a connection was found between the gradual development and exacerbation of psychotic symptoms, including delusions, anxiety, confusion, and intensified use of computer communications." (At the get-go, the patients in the study all had "relative inexperience with technology.")

One patient even came to believe that the person she was in contact with online was constantly trying to touch her physically.

It seems to have been the sheer limitlessness of the Web that drove them toward psychological malaise.Some might argue that, by virtue of their initial loneliness, these people were more vulnerable to such delusions. However, none had apparently revealed any psychotic or delusional symptoms before beginning to Facebook away.

As Dr. Nitzan said: "Some of the problematic features of the Internet relate to issues of geographical and spatial distortion, the absence of nonverbal cues, and the tendency to idealize the person with whom someone is communicating, becoming intimate without ever meeting face-to-face."

It wouldn't be hard to imagine that the minds of the apparently healthy also begin to experience something of this distortion.

I fancy that few haven't, at some time or another, obsessively refreshed a site or logged on to it hundreds of times a day, in the hope that some particular form of communication will come their way.

Dr. Nitzan talked of a "break with reality" created by the likes of Facebook.

However, as the site has become the ubiquitous means of communication, this supposed break with reality is the new reality.

I have a feeling that what is now described as psychotic and delusional will soon be seen as the normal state of human affairs.