The internet has become an increasingly important part of our lives, but scientists have discovered that some people are actually addicted to being online – that they’re dependent on the internet in the same way that some are dependent on cigarettes.

The cause, they discovered, is a genetic one.

The team, from the University of Bonn and the Central Institute of Mental Health in Mannheim, interviewed a total of 843 people about their internet habits.

An analysis of the questionnaires showed that 132 men and women in this group exhibited problematic behaviour in how they handled the online medium - all their thoughts revolved around the Internet during the day and they felt their wellbeing was severely impacted if they had to go without it.

Then they compared the genetic makeup of the problematic internet users with that of healthy control individuals.

What they found was that the 132 subjects were more often carriers of a genetic variation that also plays a major role in nicotine addiction.

Lead author Dr Christian Montag said: “What we already know about the nicotinic acetylcholine receptor in the brain is that a mutation on the related gene promotes addictive behaviour.”

He explained that 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 added: "It seems that this connection is not only essential for nicotine addiction, but also for internet addiction.

“It was shown that internet addiction is not a figment of our imagination.”