Consider this: two decades ago, there was no Facebook. Twitter hadn’t yet been conceived. Researchers and psychologists were still learning that the internet — and more so, computer games — could indeed be addictive. We hadn’t yet programmed ourselves to share intimate details of our lives on a minute-to-minute basis.

Today, that has changed. Everyone seems to have a Facebook page now, from university students in New York City to cab drivers in New Delhi. When we “like” something, we may not necessarily like it. When we “friend” someone, they may not actually be our friends.

A  study at the University of Chicago Booth School of Business concluded that tweeting or checking emails may actually be harder to resist than cigarettes and alcohol, and that while sleep and sex may be stronger urges, people are more likely to give in to longings or cravings to use social and other media.

So why, exactly, is Facebook so hard to quit?

Giving Up On Facebook

“Facebook is the millennium’s new water cooler,” says Dr. Deborah Serani, a lecturer, professor, therapist and author of the book “Living with Depression: Why Biology and Biography Matter along the Path to Hope and Healing.” “Though virtual in its design, it serves as a way for us to catch up on latest trends, share milestones, learn about juicy gossip or live vicariously through the experience of others.” Not only is Facebook a way to keep up with the Joneses, she says, it’s a way to keep track of the Joneses. It provides us with social capital.

That’s the attraction of Facebook and other social media — it promises a connection with others. But is Facebook too much of a good thing? “The reason Facebook and other forms of social media are so addicting and hard to quit is due to the instant gratification that they provide,” says Elika Kormeili, a clinical therapist in Los Angeles. “There is a sense of satisfaction each time someone ‘likes’ or comments on your status update. This in turn boosts our self-esteem and reinforces the Facebook cycle. It provides instant gratification and reinforcement.”

By nature, people are social creatures who crave human interaction, Kormeili explains. “The social media world allows us to find information on others in a way that is socially acceptable and for the most part unknown to others. We can connect with our friends, family, find people with similar lifestyles and suddenly, the world does not seem like such a big and lonely place.”

It gets hard to quit, however, because it has a highly addictive component. “Think about it,” says Jonathan Alpert, a Manhattan-based psychotherapist and author of “Be Fearless: Change Your Life in 28 Days”: “You never know when you might have a new message, friend request, or see a status update on someone else’s page. It keeps you coming back for more. Due to the unpredictable nature of this form of reinforcement it is the most powerful form of reinforcement known.

“It’s what keeps people going back again, and again, and again. Not too different from a slot machine at a casino. You put the money in, and you never know when you might win. Could be now, or it could be 10 plays from now. The occasional reinforcement or win is what provides hope for more and keeps you going back. Facebook is no different.”

Dr. Jennifer Love Farrell, a psychiatrist and addiction specialist at Amen Clinics and a diplomate of the American Board of Psychiatry and Neurology and the American Board of Addiction Medicine, feels that people like Facebook so much because it allows us to create a selected identity online. “It’s me, only better,” she says. “I can be funny, never negative, always beautiful (who posts a pic with a double chin?) and create for others a ‘memory’ or ‘picture’ of me that is entirely realistic or completely selective.”

She says she has patients who spend hours thinking of a funny comment, then rewriting it over and over. Their friends think they are hilarious and have no idea it took them six hours (and an entire distracted day at work) to come up with that snappy retort. “We can convince people we are clever, thin, popular, busy, and important; basically we can show everyone how much we rock, right?”

Your Brain On Facebook

When we first log on to Facebook, the brain’s reward-circuitry is activated, surging the levels of the feel-good neurotransmitter dopamine. The problem is that this rush is short lived and, says Serani, we soon need to find that feel-good thrill again. “This triggers a desire for many users to connect further,” she says. “Be that leaving comments, friending, liking, or reading news feeds. Dopamine is a great turn-on. It feels awesome. And though you’d think that too much of it would send you into the most blissful of places, the truth is that too much of it results in an agitated restlessness.”

For some, that’s enough anxiety to remove themselves from the situation by logging off. But for others, the craving opens up a desire to seek more social experiences, to seek that high again, which makes them stay on Facebook longer or check in more frequently in the hopes of recreating that buzz.”

A study by neuroscientists at Harvard found that talking about ourselves brings us a kind of pleasure similar to what we feel eating food, having sex or getting money. Dr. Diana Tamir, the study’s lead researcher, said the study found people were even willing to forgo money in order to talk about themselves.

Compulsive behaviors, like video games and gambling, can create a situation in which the brain doesn’t want to switch gears and gets caught in OCD-like repetition, says Farrell. “The more involvement one has on Facebook, the more feedback and attention one will get which reinforces the need to continually spend time on or improve their Facebook image. Interactions replace socializing — you can flirt in your PJs and you can post bikini photos while eating a tub of ice cream and wearing last night’s mascara.”