Social media has become increasingly popular in recent decades, revolutionizing the way people communicate, work, and entertain themselves. In fact, their use has grown exponentially in recent years. According to the Global Statshot Report 2023 [1], there were an estimated 4.76 billion active social media users worldwide, and in Italy in particular, there were an estimated 43.90 million active social media users. Furthermore, smartphones have also become the main tool for using social media, including, to name but a few, Facebook, Instagram, Twitter, and TikTok. The Global Statshot Report 2023 [1] also indicates that there were an estimated 5.44 billion smartphone users worldwide, and in Italy, there were an estimated 78.19 million smartphone users. The presence and use of smartphones has pushed communication to previously unimaginable limits; in addition to calls, users can send text messages, emails, and voice messages, as well as make video calls, all at extreme distances.

However, social media has become an important source of information, entertainment, and social connection. The tremendous amount of content available, and the constant presence of an internet connection, can lead users to feel overwhelmed and worried about missing something important. Users can also experience the fear of being separated from their smartphone or not having access to an internet connection. Furthermore, social media users may be constantly exposed to news, events, and activities that they feel compelled to participate in. If they feel that they are not continuously connected, they might miss an important or interesting experience, which can generate anxiety and stress. These feelings are related to constantly experiencing the need, if not the compulsion, to check their social media accounts so as not to miss anything. It is also important to note that social media users can develop an overdependence on the platforms, which is driven by the fear of missing out on something or falling behind their friends and acquaintances, and this can lead to an ongoing obsession with social media as well as a negative impact on mental health, as the previously mentioned constructs highlight.

Concerning the above considerations, research to date has outlined one construct that accounts for the emergence of real forms of contemporary malaise [2]: the fear of missing out (FoMO) [3,4]. The FoMO is a concept that refers to a state of anxiety experienced by those who use social media; it is caused by the perception that one’s acquaintances are experiencing, or are in possession of, something rewarding that one is not [3,5], which creates a feeling of being excluded or left behind [6]. The construct involves the desire to constantly stay in touch with what others are doing. Research has highlighted four main correlated dimensions: (1) social needs, such as the need to belong to a group [3]; (2) the need to seek approval from others, and accompanying low self-esteem [7]; (3) the emotional problems that emerge in situations where there are difficulties in accessing social media [8]; and (4) social media use which prevents individuals from engaging in daily activities [9].

The construct of FoMO thrives in the digital world, especially concerning the use of social networking sites (SNSs), which are seen as privileged channels for maintaining social connections [10] and play a very important role with respect to gratifying social needs [8]. Most notably, these include the need to belong [11] and the need to increase one’s popularity [12]. In this regard, in line with the perspective of self-determination theory (SDT) [13,14], a lack of fulfillment of the aforementioned psychological needs may be related to an increased fear of being missing out on something, which leads to using social networks as a self-regulatory tool to satisfy one’s psychological needs [8].

Although the FoMO construct is not yet fully established, and even though its role in the development of maladaptive use of internet communication applications is not yet understood, empirical research has highlighted how it can serve as a mediator between psychopathological symptoms and the consequences of maladaptive use of SNSs on the smartphones [15]. It may also mediate between motivational deficits and social media engagement [16] and between deficits in emotional needs or problems and social media use [3]. FoMO appears to be a predictor of smartphone addiction [17,18] and emotional distress [5], and international research has also highlighted a significant negative correlation between FoMO and self-esteem [19,20,21]. Furthermore, since FoMO appears to be related to online social media use and addiction [22,23,24,25,26,27], Sette and colleagues [28] recently proposed the concept of online fear of missing out (On-FoMO) which, indeed, was strongly positively correlated with psychopathological symptoms and social media addiction [29,30].

Even though the use of modern online technology has repeatedly been associated with positive effects (such as entertainment, social interaction, and the development of cognitive skills, among others), several studies have highlighted relevant concerns about its excessive use [31,32]. In particular, and according to Andreassen and Pallesen [33], the addictive use of online technology is characterized by “being overly concerned about online activities, driven by an uncontrollable motivation to perform the behavior, and devoting so much time and effort to it that it impairs other important life areas” (p. 4054). Although currently not defined as a disorder in the Diagnostic and Statistical Manual of Mental Disorders (5th Edition Text Revision; DSM-5-TR) [34] or in the International Classification of Diseases (11th Revision; ICD-11) [35], social media addiction could be defined as potentially addictive behavior, with disunity in terminology regarding labels such “excessive use”, “pathological use” or “problematic use”, all concepts referring to social media use disorders.

However, addictive social media behaviors may also be understood through reference to the six criteria proposed by Griffiths in his model [36]: mood modification (i.e., change in emotional states due to engagement in social media use); salience (i.e., cognitive, emotional, and behavioral preoccupations with the social media use); tolerance (i.e., the ever-increasing use of social media); withdrawal symptoms (i.e., experiencing emotional and physical symptoms due to restricted or discontinued use of social media); conflict (i.e., intrapsychic and interpersonal problems arising from social media use); and relapse (i.e., addicts quickly return to excessive social media use after a period of abstinence).

Empirical research has highlighted the relationship between addictive technological behaviors, anxiety, depression, and other psychiatric disorders [32,37,38,39]. Research has also demonstrated the role played by specific demographic characteristics. Indeed, younger individuals, as well as individuals not in relationships, tend to more frequently develop social media addiction [31,32,40]. Finally, several studies have found a significant negative correlation between social media addiction and self-esteem [19,41,42,43], thus indicating that addictive social media use is linked to a negative self-concept, and thereby to lower self-esteem.

4. Depression, Fear of Missing Out and Social Media Addiction