The characteristic symptoms of Obsessive-compulsive disorder (OCD) are the presence of obsessions or compulsions, or both, as described by Criterion A in the Diagnostic and Statistical Manual of Mental Disorders 
. Obsessions are repetitive and persistent thoughts, images, or urges that enter the mind in a recursive, intrusive, and unwanted way, causing marked distress or anxiety. Mainly for this reason, OCD patients attempt to ignore or suppress these obsessions (e.g., avoiding triggers or using thought suppression) or to neutralize them with another thought or action (e.g., performing a compulsion). Compulsions (or rituals) are repetitive behaviors or mental acts that the individual feels compelled to perform in response to an obsession; however, they are not realistically related to what they are supposed to neutralize or prevent, or are clearly excessive. Most individuals with OCD have both obsessions and compulsions 
, and they sometimes seem to have poor insight, high comorbidity, high role impairment, and a high probability of seeking treatment 
, maybe due to a specific blood flow pattern in the brain 
OCD diagnoses are not particularly usual but fully 28.2% of respondents to Ruscio and colleagues 
reported experiencing obsessions or compulsions (O/C) at some time in their lives. In the DSM-5
, between a 2–3% lifetime prevalence of OCD is reported, with equal distribution between the two sexes.
2. Types of OCD
There are multiple OCD types categorized as up-to-date subgroups of OCD that are also used as diagnostic criteria for DSM-5
in field studies. These groups can be summarized as checking, contamination, hoarding, indecisiveness, and just right [3,8,9]
. Although the types of OCD resemble each other, all of them have distinctive features that separate one from the others.
One of the most common types of subclinical OCD is hoarding, characterized by a massive collecting behavior and the consequent failure to get rid of the collected objects 
. The DSM-5
defines hoarding as an OCD-related disorder 
with a persistent tendency to accumulate objects, regardless of their value, until they clutter domestic areas, making them unusable and causing psychological distress 
. This difficulty is caused, on the one hand, by a compulsive need to store such objects, and, on the other hand, by the discomfort felt thinking of getting rid of them 
In the OCD type of “contamination”, obsessions and compulsions are related to both realistic and unrealistic contagions or contaminations [11,12,13,14,15]
. Sometimes, the feelings of dirt are triggered even by immoral thoughts, memories of traumatic events, or mental images 
. Of all the manifestations of OCD, the obsession with contamination is the most common in nature, and the associated cleaning compulsions are the second most common form of OCD compulsion 
People affected by the “checking” subtype of OCD are engaged in safety checking compulsions, with the main aim of preventing obsessive thinking related to damage, leaks, or harm to other people or oneself and to reduce uncertainty 
. Typical examples of compulsive checking are verifying that family members are safe, repeatedly retracing the route one drove, and repeatedly checking that doors and windows are securely closed 
. Checking is often carried out multiple times and can require hours to be completed, affecting people’s lives consistently 
“Indecisiveness” is defined by longer decision times as well as by increased searches for information 
, and the literature shows that it is associated with OCD tendencies and symptoms 
. People experiencing obsessions postpone or avoid decisions in order to minimize the risk of making mistakes or not being perfect 
. For example, indecisiveness may affect the amount of time needed for repetition of the compulsive behavior, such as the number of closings needed to actually close the door or knowing when to stop handwashing to be indeed clean 
. OCD patients may also avoid situations when decision making is required 
or tend to plan every aspect of their lives to reduce uncertainty 
. For many researchers (see [25,26]
), indecisiveness is only a “trait” of OCD patients, but the most used OCD Inventory 
includes an indecisiveness dimension (i.e., sub-scale) related to OCD symptoms.
“Just right” is an OCD subtype that is characterized by uncomfortable feelings of things not being right. Patients also report feeling driven to perform an action until this uncomfortable sensation subsides, in order to feel things are “just right” 
. The main symptoms associated with the not-just-right experiences (NJREs) are perfectionism, ordering, symmetry obsessions, compulsions, indecisiveness, and procrastination 
e hresearchers h
ave already addressed indecisiveness in the previous paragraph, showing that procrastination in OCD patients is due to the feeling of imperfection in their actions 
In the ordering and symmetry symptoms, the patient does not tolerate objects placed in a disordered or asymmetrical way, even partially. This gives them an unpleasant feeling of lack of harmony and logic 
. Finally, NJREs are strongly linked to perfectionism 
, that is, the occurrence of NJREs increases significantly in people that experience maladaptive domains of perfectionism (e.g., concern over mistakes or doubts about actions).
3. Social Media as a Social Arena for Both Non-OCD and OCD People
In the recent decades of rapidly developing technology, social media (SM) have become an important driver for acquiring and spreading information in different domains, such as business, entertainment, science, crisis management, and politics [30
and they also affect psychological processes and social interactions 
Unfortunately, these changes are not only positive: researchers have found a new syndrome named “virtual factitious disorder” or “Munchausen by internet” 
. These patients pretend to have online disorders to gain attention, gather sympathy, display anger, or control others with different motivations and consciousness 
. So, technological improvements could have a critical impact on psychological diagnosis.
Furthermore, many people have started using social media as their primary source of information, thanks to the speed with which it is disseminated online 
. Despite this, the quality of information and its truthfulness seems to be decreasing 
. In addition to the spread of fake news, the phenomenon of fake profiles has emerged, which is the use of false credentials to create an Internet/social-media profile [35,36]
. According to Facebook, 5–6% of registered accounts are fake 
Additionally, Good 
identifies three shared functions of social media: (1) documenting friendship, (2) navigating new media abundance, and (3) communicating taste and building cultural capital. That is because higher levels of online engagement are due to the nature of social media such as the easy access, low costs, and fast dissemination 
. The function of documenting friendships and collecting friends on social media could be challenging activities for a high-hoarding-scores person because these individuals are expected to collect and hoard stuff without need 
and this feature of social media can lead them into practicing various collecting behaviors.
At this time, there are not many studies in the literature investigating the impact of SM on OCD people, and the ones wthe research
can find are fairly recent [40,41]
. Even less analyzed has been the impact and the effects of social media on the specific subtypes of OCD. The only, and not compelling, evidence is reported by Luxon and colleagues 
and concerns hoarding behaviors. The authors found that physical OCD is akin to its digital counterpart based on their study on people’s behavior on Pinterest. They displayed a positive correlation between the number of digital belongings on said platform and electronic object attachment. Some significant relationships emerged between electronic-object attachment, hoarding severity, difficulty discarding, and acquisition, and several different aspects of Pinterest use (e.g., amount of time spent on Pinterest), as well as self-reported enjoyment and importance of Pinterest. Higher levels of physical acquiring behaviors predicted increases in anxiety, fear, and anger and a decrease in relaxation and happiness after being asked to discard electronic possessions. Nevertheless, there is a gap in the literature on online hoarding behavior because it is a quite new phenomenon.
In addition, when the COVID-19 pandemic started in the last quarter of 2019, people were forced not to leave their homes for a long time 
. The pandemic situation has increased the use of social media to more than before 
, primarily to create and maintain social bonds and contacts with friends and family 
. The COVID-19 pandemic has also increased the time spent on online playful activities such as surfing the internet and making use of video games and SM [46,47]
. Moreover, Banerjee 
attested that, during the lockdown, hoarding behavior increased (e.g., masks, sanitizers, food, medicines). For all these reasons, the urge to study SM effects on OCD and OCD subtypes is now more important than ever. Nowadays, lots of psychologists are wondering if social media and online activities may be included in OCD symptoms. Van Bennekom and colleagues 
propose adding obsessions, compulsions, and avoidance behavior related to new technologies (such as social media and smartphone technology) as symptoms on the Yale-Brown Obsessive-Compulsive Scale symptom checklist for OCD.
Lastly, the scientific literature stressed that individuals with higher levels of OCD symptoms may experience increased psychological distress and fatigue due to fear of missing out on social media 
. This fear seems to push OCD people to more intense use of social media and sometimes addiction 
. As time spent on SM increased, OCD symptoms, interpersonal sensitivity, depression, anxiety, anger–hostility, phobic anxiety, paranoid thinking, psychoticism, and additional scaly symptom levels increased too, thus affecting OCD people’s mood and well-being