While the use of social media in health care remains in its infancy, a number of themes emerge on how this communication technology is being leveraged to better understand health habits of adolescents and young adults and improve health care delivery to this population. We have found that there are four primary ways in which social media have been used to interact with the adolescent and young adult population.

Social media can offer powerful insights into the lives of young people. The majority of the studies in this systematic review were observational studies that either analyzed content of social networking profiles of adolescents and young adults, or assessed social media use though questionnaires or interviews of adolescents and young adults regarding their use of social media platforms. Common social behaviors that were observed related to sexual behaviors [26,33-35,44-46,55,57,60,73-75, 77,78,90,93,95-97], alcohol, tobacco, and other drug use [26-30,32,45,47,50,52,57,63,65,68,83,92,94,101], mental health [24,25,31,36,39,48,59,62,64,67,71,85,91,98,99], and online safety [23,37,38,66,81,82,84,89]. By sharing life experiences with the larger public, social media users offer a window into their lives, often revealing the social pressures and expectations they experience. Their postings offer opportunities for HCPs to identify risky health behaviors and health problems that might have been missed during routine health screening, thereby offering opportunities for intervention.

The frequency with which mental health issues are discussed among young people using social media suggest that this offers a potentially fruitful area for the application of social media to help improve the lives of its users. A positive correlation has been found between depressive symptoms and time spent on online social networks [44], suggesting that depression may be common among individuals who spend a significant amount of time on social media. Another study found that over 50% of secondary school students experienced a need for mental health support and 47% believed that SNS could help with these mental problems [45]. Given that adolescents and young adults are already turning to social media for advice and shared experiences, it may behoove HCPs to listen and to seize this opportunity to reach out with accurate information and support.

By enabling individuals to share their thoughts, behaviors, and experiences with a larger audience, social media can also contribute to the establishment of social norms leading to the creation of pressures to “fit in” among adolescents and young adults. A well-known problem, confirmed by analysis of social media content, is the high prevalence of alcohol use among adolescents and young adults: 25% of teenagers ages 16-17 years old [16], 56% of 17-20 year olds [19], and 85% of college students [26] display references to alcohol on social media. The high prevalence of alcohol references on these “intoxigenic” digital spaces [27], a term used by one author to describe pro-alcohol sentiments on social media, leads to the normalization of alcohol use. Given that 60% of college students report potentially problematic alcohol use [28], such normalization of high-risk behavior online adds to the already daunting challenge that HCPs face in counseling against alcohol abuse. However, the use of social media by providers for this purpose may be limited by its perceived acceptability by adolescent and young adult users. One study investigating preferred means of communication regarding mental health issues found that adolescents did not feel comfortable having an unknown HCP screen their social media sites, and described having a stranger screening their Facebook pages for signs of depression as “creepy” [29].

The normalization of high-risk behaviors is not limited to alcohol alone. The use of tobacco and other drugs, violence, sexual behavior, and even suicidality are also commonly displayed on social media platforms. Tobacco imagery is frequently shared on social media [30] and 9% of teenagers aged 16-17 years describe or display cigarette use on their SNS profiles [16]; 15-24% of adolescents also displayed sexual references [20,31]. Such postings have particularly concerning implications, as they may increase sexual expectations when adolescents are using social media to evaluate potential partners [49]. Even suicidality has been found to be impacted by social media through the availability of suicide stories [50].

Online safety is a major concern among studies involving social media: 9% of children ages 10-17 years report having been harassed online over the course of a year [14] and 4% received unwanted sexual solicitation [43]. This has important implications, not just for safety, but also for mental health as cyber-bully victims have higher depression rates when compared to traditional “offline” bully-victims [51]. Adding to the potential risk is the fact that even potentially sensitive behaviors are typically not posted anonymously: one study found that 97% of SNS contained personal identifiers, such as including a profile photo, full name, and hometown [32]. However, privacy settings within different SNS varies and information that may be viewed publically may change over time.

A number of studies have used social media platforms as channels to provide health information to educate and invoke behavior change among young people. These platforms have tended to be disease-specific, providing information on childhood cancers [33,34], diabetes [53], and organ-donation [86]. Although it has been suggested that social media may not be a preferred method of contact regarding health information [54], most such studies nonetheless demonstrated a positive impact on their target audiences. For example, an intensive organ donation program utilizing multiple social media platforms to provide organ donation statistics and information was able to increase organ donor registration by 28% [86]. Another study, targeting adolescents at high risk for sexually transmitted diseases, found that brief preventive counseling in the form of a message sent by social media reduced the display of “risky” behaviors online [24].

Social media also provides an opportunity for the health care community to become involved in discussions with adolescents and young adults, thereby engaging them in ways not possible within the traditional office setting. This may indeed be the true “gold mine” of incorporating social media into health care for this population. As supported by our review of the literature, researchers have only recently begun exploring ways to reach out to adolescents and young adults through social media in the hopes of creating online communities to improve patient-provider communication. Studies performed to date have primarily assessed the acceptability of using social media through observational studies to interact with young people and have achieved mixed results, likely reflecting our collective lack of experience with the use of social media for this purpose. For example, a study that invited members to join an interactive Web 2.0 portal consisting of an extensive library of health education information, in the form of text, videos, and simulation software, social networking capability through message boards and blogs, services for renewing medications and scheduling appointments, and sending questions to the medical team, found that participants welcomed this type of health-related community as a source of information and support [53]. Nevertheless, engagement with the Web 2.0 portal was hindered by the lack of frequently updated information and complicated log-in procedures [53]. Clearly, a social media platform that fails to sustain user engagement is unlikely to be an effective means of improving health care outcomes in the long term [87].

Beyond engaging adolescents and young adults in discussions about health, social media can also be used in research recruitment efforts. A number of studies identified participants from their postings on social media and subsequently approached them about participating [21-23,29,55,56,93]. Another study was able to leverage social media to locate study participants who would have otherwise been lost to follow-up [92]. In addition to being a cost-effective and efficient means of research recruitment, social media enables researchers to reach a demographically representative sample of adolescents and young adults, including those traditionally underrepresented in research (eg, high-risk individuals and those living in rural communities), and also by providing real-time monitoring of recruitment efforts [94]. Such findings suggest that recruitment of adolescents and young adults for research studies may be achieved more effectively and efficiently through social media channels.

Despite the wealth of opportunities, there remains concern and potential barriers to using social media for health care applications in the adolescent and young adult population. Privacy and confidentiality issues are a concern, particularly when discussing sensitive or stigmatized health topics online through non-secured formats, and young people have expressed a preference for accessing credible health-related information anonymously [80]. Because adolescents generally prefer to seek help from their peers and people that they know rather than from HCPs and strangers, developing an acceptable way to leverage social media for health care purposes may be difficult [23,29]. In their efforts to interact with young people over social media in ways that will engage them, HCPs must be mindful of maintaining professional boundaries and patient privacy. Another concern is that HCPs would be expected to keep up with this ever-changing, fast-paced dialogue on social media that can evolve and spread quickly, with potentially dire consequences. For example, in the case of suicide contagion, it may not be possible for providers to recognize the problem and intervene quickly enough to prevent adolescents and young adults from harm. Furthermore, statements made on social media may not reflect the writer’s actual state of health or behaviors, particularly if adolescents and young adults exaggerate or falsify information that they share over social media as a result of social desirability bias. It is important to also note that the majority of studies that we reviewed focused on publicly available content on social media, and what teens share openly may not fully reflect the true extent of their behaviors in their day-to-day lives. Last, because of the open nature of social media and the potential for posting of exaggerated, falsified, or untrue statements on these platforms, the credibility and trustworthiness of the posted content will remain an issue, unless there are systems in place to monitor the quality and content of information on social media platforms.

The strengths of our paper lie in the comprehensive and systematic approach we took to review the literature, along with our deliberate and detailed approach to reviewing each full-text article. Nevertheless, there are limitations to this systematic review that warrant considering. First, it is possible that, despite our attempts to capture all pertinent articles through the use of numerous carefully selected search terms, some relevant studies may have unintentionally been excluded. Furthermore, because many social media platforms (including Twitter, Pinterest, and Flickr) do not include documentation of age, many of the observational studies on these platforms were excluded as the age of the study population could not be confirmed. Another potential limitation of the study is in our inclusion criteria for age. We chose to include research involving adolescents as young as 11 years old up to young, college-aged adults of ages up to 25 years due to similarities in the health risks and concerns, reported behaviors, and patterns of social media use. This broader age range provided a greater volume of studies, which we believe offered more comprehensive insight into the potential uses of social media to impact the health of young people. Furthermore, it is possible that studies pertinent to this review may have been missed as a result of keywords used in the article selection process. However, trends for use of SNS within adolescents and young adults were observed, as described above.

Social media and social networking platforms are relatively novel ways of communication, driven primarily by young people, which have been growing and changing ever since their emergence in the early 21^st century. Currently, over 70% of adults obtain health information predominantly online [102], but given the growing popularity of social media, it has the potential of becoming a more significant source of online health information in the coming years. Users of social media and those in other fields, such as the advertising industry, understand how the medium can be leveraged for the sharing of information, but the medical and scientific community has been slow to embrace these technologies. Ironically, many health care providers overlook the fact that when they themselves search for health information online on search engines, they often find themselves on Wikipedia, which itself is a social media platform.

Understanding how individuals engage on SNS and consume information will enable HCPs and health care provider organizations to make their content and patient engagement strategies more online-friendly. The number of people using social networking platforms daily continues to grow steadily and this ubiquity can help HCPs engage with patients on a platform they may already be using. For example, communicating with patients about office appointments, lab tests, or even allowing them to ask questions and share content directly through SNS could greatly facilitate patient-provider communication and increase patients’ participation in their own care. Additionally, with the emergence of mobile technology, SNS are becoming increasingly “real time”, immediate, and local. The combination of SNS with mobile technology makes it possible to learn about patient behaviors and daily habits, and to intervene with relevant and timely messaging, coaching, and interventions. Furthermore, computer-generated predictive analytics could be established to screen SNS for keywords or images associated with health care-related issues, automating the process of SNS surveillance in a more patient-accepted format, which may feel less “creepy” to adolescents and young adults while still capturing important opportunities for positive intervention. In the future, the rich data available through SNS and mobile technology may enable HCPs to become more proactive about health care delivery.

Although many HCPs remain timid about the use of social media in the care of patients, this review demonstrates that social media is already being used for a variety of purposes and in a number of different ways to engage, educate, and improve the health of its users. Most studies done to date have been observational in nature, examining how adolescents and young adults communicate on social media and the resulting implications on their health. Although these explorations are essential, further exploration and development of these strategies into building effective interventions that can positively impact the health of young people is warranted. One of the greatest challenges in harnessing social media is the constant and rapid pace of evolution, including the continual development of new technologies and the ever-changing popularity and adoption of specific platforms among different user demographics. In order to stay on top of this rapidly evolving field, ongoing study of the use of SNS by adolescents and young adults will be critical. Further research is necessary to establish whether social media can be an effective tool to help achieve positive health outcomes in the adolescent and young adult population.