What causes Internet addiction

Researchers and therapists are increasingly closing in on it, he said.

Over the past years,the Bonn researchers have interviewed a total of 843 people about their Internet habits.

An analysis of the questionnaires shows that 132 men and women in this group exhibit problematic behaviour in how they handle the online medium; all their thoughts revolve around the Internet during the day,and they feel their well-being is severely impacted if they have to go without it.

For the study,the researchers from the University of Bonn and the Central Institute of Mental Health in Mannheim compared the genetic makeup of the problematic Internet users with that of healthy control individuals.

This showed that the 132 subjects are more often carriers of a genetic variation that also plays a major role in nicotine addiction.

What we already know about the nicotinic acetylcholine receptor in the brain is that a mutation on the related gene promotes addictive behaviour, Dr. Montag said.

Nicotine from tobacco fits – just like acetylcholine,which is produced by the body – like a key into this receptor. Both these neurotransmitters play a significant role in activating the brain”s reward system.

It seems that this connection is not only essential for nicotine addiction,but also for Internet addiction, he said.

The actual mutation is on the CHRNA4 gene that changes the genetic make-up for the Alpha 4 subunit on the nicotinic acetylcholine receptor.

Within the group of subjects exhibiting problematic Internet behaviour this variant occurs more frequently in particular,in women, Dr. Montag added.

This finding will have to be validated further because numerous surveys have found that men are more prone to Internet addiction than women.