Spend too much time on Facebook?  Can't get enough LOLcat videos?

You no longer need to be ashamed.  You may have a disease. Psychologists interviewed a total of 843 people about their Internet habits and an analysis of the questionnaires showed that 132 men and women in the group exhibit problematic behavior in how they handle being online; all their thoughts revolve around the Internet during the day, and they feel their wellbeing is severely impacted if they have to go without it.

The researchers from Bonn got together with counterparts at the Central Institute of Mental Health in Mannheim and compared the genetic makeup of the problematic Internet users with that of healthy control individuals. Their analysis found that the 132 subjects are more often carriers of a genetic variation that also plays a role in nicotine addiction. 

Even as a second order relationship, cigarettes can't catch a break. 

"What we already know about the nicotinic acetylcholine receptor in the brain is that a mutation on the related gene promotes addictive behavior," explains Privatdozent Dr. Christian Montag from the Department for Differential and Biological Psychology at the University of Bonn. "It seems that this connection is not only essential for nicotine addiction, but also for Internet addiction."

 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, he says.

Women impacted most!

The actual mutation is on the CHRNA4 gene that changes the genetic makeup for the Alpha 4 subunit on the nicotinic acetylcholine receptor. "Within the group of subjects exhibiting problematic Internet behavior this variant occurs more frequently – in particular, in women," says Montag. This finding will have to be validated further because most other surveys have found that men are more prone to Internet addiction than women.

"The sex-specific genetic finding may result from a specific subgroup of Internet dependency, such as the use of social networks or such," he speculates and added that studies including more subjects are required to further analyze the connection between this mutation and Internet addiction. "But the current data already shows that there are clear indications for genetic causes of Internet addiction."

He added that with the mutation, a biological marker had been found that would allow to characterize online addiction from a neuro-scientific angle. "If such connections are better understood, this will also result in important indications for better therapies." 

Montag C, Kirsch P, Sauer C, Markett S, Reuter M., 'The role of the CHRNA4 Gene in Internet Addiction – A Case-control Study', Journal of Addiction Medicine, DOI: 10.1097/ADM.0b013e31825ba7e7