Internet addictions — especially to social media — have been well documented. And the truth is, we're feeling like we might have a touch of Facebook addiction.

But what's the psychology behind this disorder?

As it turns out, receiving and answering a notification results in a hit of dopamine, a chemical neurotransmitter associated with the motivation and reward response in the human brain. Dopamine is also released in high quantities when we consume drugs or have sex. Social media notifications can have the same addictive effect.

Is this addiction real, though? In China, Taiwan and South Korea "Internet Addiction Disorder" is already accepted as a psychological diagnosis. Next year it will be included in the fifth edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-V), the American "bible of psychology."

Facebook and Internet addiction can have damaging effects, such as a decrease in our attention span — in fact, since 2000, our collective attention span has decreased by 40%.

Check out the infographic below to find out more facts about Internet and Facebook addiction.

Infographic by Best Masters in Psychology. Homepage image courtesy iStockphoto, AngiePhotos.