Carried out by scientists from the University of Pittsburgh School of Medicine, the team sampled 1,787 US adults aged 19 to 32 in 2014.
Using questionnaires, the participants were asked about the amount of time and frequency of their social media use on 11 most popular social media platforms at the time -- Facebook, YouTube, Twitter, Google Plus, Instagram, Snapchat, Reddit, Tumblr, Pinterest, Vine and LinkedIn.
The team also measured participants' perceived social isolation using a validated assessment tool called the Patient-Reported Outcomes Measurement Information System.
After controlling for a variety of factors, the results showed that participants who used social media for more than two hours a day were twice as likely to feel socially isolated compared to those who spent less than half an hour on social media each day.
In addition, those who visited social media sites 58 or more times per week were around three times as likely to feel socially isolated than those who visited these sites less than nine times per week.
"This is an important issue to study because mental health problems and social isolation are at epidemic levels among young adults," said lead author Brian A. Primack, commenting on the findings.
"We are inherently social creatures, but modern life tends to compartmentalize us instead of bringing us together. While it may seem that social media presents opportunities to fill that social void, I think this study suggests that it may not be the solution people were hoping for."
The results are also significant as social isolation has previously been associated with an increased risk for mortality.
The researchers have several theories for how an increased use of social media could also increase feelings of social isolation, suggesting that it could be that social media use replaces authentic "real-life" social experiences, because the more time a person spends online, the less time there is for real-world interactions.
Certain aspects of social media may also lead to feelings of isolation and being excluded, for example being able to see photos of friends having fun at an event to which they were not invited, and social media's highly idealized representations of others' lives can also lead to feelings of envy and a possibly false belief that others around us are leading happier and more successful lives.
Although they pointed out that more research needs to be done, the team are now encouraging doctors to ask patients about their social media use and advise them how to reduce that use if it appears to be contributing to feelings and symptoms of social isolation.
The results can be found online published in the American Journal of Preventive Medicine.