It is often not the smartest people who suffer from loneliness. Although they protect themselves from it much more carefully. But if a person who is not distinguished by intelligence is left alone, then he has nothing to occupy himself with, therefore, he is bored and suffers. Regarding smart people, it is true that they are more often left alone and more often and more deeply realize it, think about it, analyze it, because:
1. Intelligence is a relative concept, but an intelligent person definitely has the habit of thinking a lot, comprehending what is happening around him, going deeper into his thoughts and attaching great importance to them. Also, an intelligent person needs to regularly obtain new information, information, knowledge, and not just any kind, but of a certain quality and on certain topics (an intelligent person is distinguished by legibility and fastidiousness in intellectual and cultural content). No matter how high a person’s intelligence may be, without regular replenishment of new high-quality information and training of thought processes, an intelligent person will soon cease to be so. Moreover, he will certainly suffer in the absence of this nourishment, experience “withdrawal” (just as an athlete cannot do without regular training). And all of the above takes time. Doing this while communicating with a lot of people at the same time is difficult. Communication is distracting, draws attention to yourself, and takes away energy. Therefore, every smart person realizes that he needs solitude. And he is not afraid to be alone, because he is not bored by himself. Solitude becomes regular - and this is loneliness.
2. Sometimes people with high intelligence have difficulty communicating because they do not know how (and do not want) to turn off the analysis of what is happening. An ordinary person chatters whatever comes to his mind, and does it easily and confidently - a smart person goes through the options of what can be said in his head, trying to choose the best one. An ordinary person is fully involved in the situation and communication; an intelligent person never stops analyzing and drawing conclusions. It is more difficult for a smart person to be fully charged with other people’s emotions, to sympathize - he is distracted from a specific situation, it is easier for him to look at it abstractly, from the outside. All this is noticeable, and communicating with an intelligent person seems more difficult to ordinary people.
3. An intelligent person does not like the topics that most people talk about. And it’s not just that smart people read other books and watch other films. The fact is that many smart people are of little interest in the everyday, practical part of life. Who is wearing what, what to buy where, who is on what diet, what position is best to have sex - most people discuss this regularly. People whom I have met in life and consider smart, understand this poorly and do not see much sense. The very process of discussing mundane topics strains an intellectual person who is used to thinking about more abstract concepts. Therefore, smart people are excluded from a huge part of the universal human discourse :) Of course, not all. Another part of life that intellectuals are not always interested in discussing is people and relationships. That is, in a general sense, we can talk about this, but when it comes to specific Katya, Vasya and Pete, an intelligent person is bored. And even more so if it is primitive gossip.
4. An intelligent person often differs from the majority in views, values and lifestyle. In fact, this is not a reason to be lonely. The reason is that an intelligent person attaches great importance to his views and defends them even when the situation does not imply this. Most people find it difficult to admit they are wrong, it is difficult to withstand the pressure of an intelligent person on their values, it is difficult to defend them - it is easier to curtail communication. In turn, it is difficult for smart people to continue communicating with those with whom they do not share the same views; for them it is too serious.
Arina, thank you for the pleasure of reading your wonderful answer! I would like to copy it into my notebook with quotes from smart people - you are a subtle and deep person! It was very interesting to read your answer, because what you wrote is an accurate description of me. I don’t know if I’m smart , or quite ordinary, but this “habit” of constantly analyzing everything, thinking about the answer and taking seriously the thoughtless tweeting of people does not leave a chance to become the life of the party, or just a sweet and pleasant person.
You are right, loneliness most often upsets people who are bored of being alone with themselves. It is not boring or bad for a reflective person to be alone, he is bothered by all this fuss with communication, talking about “nothing” - it leaves a feeling of emptiness and fatigue And on the contrary, an interesting conversation brings pleasure and enriches spiritually, gives the joy of knowing this world and oneself. But there are not as many interlocutors capable of such conversations as we would like, so there is nothing else left but to simply be alone with oneself and books. But it's so interesting!
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A recently published scientific study has revealed how our social needs affect our happiness. It turned out that there is a group of people who do not need friends at all. The small number of “lucky” people who adore solitude include very intelligent representatives of our society. Let's try to figure out why intellectuals look at happiness in their own way? Until now, it was believed that only those who are surrounded by countless friends experience satisfaction in life.
"Savannah Theory"
The international study was authored by Norman P. Lee (Singapore Management University) and Satoshi Kanazawa (London School of Economics). During the experiment, scientists looked at how the “savannah theory” affects the feeling of happiness of a modern person. This famous theory is otherwise called the “inconsistency hypothesis” in scientific circles. Its essence is simple: some scientists argue that modern people perceive happiness in the same way as our distant ancestors. The psychology of a person living in the 21st century has not changed at all since the time when the first people lived in the African savannas. According to adherents of this theory, we still feel the need for cooperation with other members of society, despite the fact that we could survive perfectly well without outside help. Is this really true? 
The study covered urban and rural residents
The researchers analyzed data from several surveys conducted among young people aged 18 to 28 between 2001 and 2002. In total, the sample covered more than 15 thousand people of both sexes. During the work, close attention was paid to searching for a correlation between the respondent’s place of residence and satisfaction with the quality of life. For example, cities have higher population densities than rural areas. At the same time, in villages people have the opportunity to see friends more often. Scientists have been trying to piece together how friendships can affect overall happiness. Are people in cities really less happy? 
Inside a large community
In general, the study confirmed the scientists' initial assumptions. The majority of respondents living in densely populated areas noted insufficient life satisfaction. As you can see, the “savannah theory” has found further confirmation. Scientists explain this phenomenon as follows: due to their nature, people feel awkward within a large community where all people, in fact, are strangers to each other. From an evolutionary point of view, the human brain is adapted to interact in small groups of no more than 150 people. Many scientific facts speak about this. 
Based on early scientific research
The neocortex (new cerebral cortex) of humans and other primates implies that the size of the living group does not exceed 150 individuals. In other words, we cannot interact with many people at the same time. This is also indicated by computer modeling, with the help of which the risk avoidance mechanism was built. We feel safer when our community is smaller than 150 people (based on studies of telephone contacts and the number of greeting cards sent.) If our community is larger than 200 people, we tend to split in two, which encourages greater cooperation. But here the researchers identified one clear discrepancy. It turned out that among numerous groups only people with an average level of intelligence feel bad. Also, this segment of the population is in dire need of friends. 
Respondents with a high level of intelligence have the opposite needs
Scientists were surprised to note that respondents with a high level of intelligence indicated different needs. As it turns out, a smart person feels happier when he is in splendid isolation. He does not need friends, because he is used to relying on himself and can achieve everything on his own. The absence of friends does not bother the intellectual in any way, and he satisfies the need for social life by being in the company of strangers in a large metropolis. Lee and Kanazawa explain this phenomenon this way: the intellectual is focused on his own achievements, and he puts his own desires at the forefront. 
For him, those around him are an irritating factor that prevents him from moving towards his goal. Friends take up valuable time and distract a smart person. As it turned out, intellectuals long ago formed their own system of values and priorities, where public life does not occupy the first place.
Smart people are often unlucky in love. It is difficult to find a person who matches your level of intelligence and is also an interesting, sensitive interlocutor. And if you really want to dream, then the ideal partner should be well versed in the psychology of the opposite sex and be able to act in accordance not only with his own idea of relationships, but also see through the eyes of another. What prevents smart people from meeting their soul mate?
1. They analyze feelings - both their own and others'.
Smart people are brilliant at collecting information and drawing conclusions. And this ability plays a bad joke on them: it is easier for them to “escape” from a relationship at the first sign of problems than to sort them out. Since we don’t understand each other, it means we simply don’t fit in, goodbye.
2. They take a long time to open up.
Smart people's brains are constantly working, bringing to the surface all sorts of details and reasons why things could change for the worse. As a result, they find it difficult to open up to others: they understand that relationships are always a risk. Therefore, they carefully weigh the pros and cons. During this period of reflection, they may appear cold and distant, but this is only on the surface.
3. They rely on past experience.
Smart people are afraid that every next relationship can be destroyed by the same thing as the previous one. But it is difficult for them to realize that this is not necessarily the case. Past experiences are transferred to the people who are near them at the moment.
4. Loneliness is their conscious choice
This is often true. Smart people are aware that it is better and more comfortable to be alone than with someone who is “not their own.” This is their deliberate decision. In most cases, smart people become lonely, not because it just happens that way, but because they are comfortable being with themselves.
An authoritative publication in the field of psychology recently published the results of a very interesting study based on the connection between the ability to socialize, the ability to build interpersonal relationships and the level of intelligence. Scientists aimed to determine the impact friendship has on a person’s sense of happiness.
Psychologists have suggested that people living in densely populated areas, particularly in densely built cities, are more satisfied with their lives than those living in rural areas. The logic was that the more often a person communicates with friends and loved ones, the happier he should be. Well, it’s easier to meet friends where “everything is nearby.”
The study says that, as expected, the level of life satisfaction is directly related to the frequency of social contacts. People who live in denser areas generally feel happier than others. However, the influence of intelligence turned out to be much more important. Intellectuals, smart people feel happier when they are alone. But when they need to communicate frequently with acquaintances or friends, discomfort appears - the person is overcome by sadness and irritability.
The authors of the work were Satoshi Kanazawa and Norman Lee, who have been studying the conditions of human life in big cities for many years. The anomaly described in the study was discovered only recently.
15 thousand people from 18 to 28 years old participated as volunteers in the experiment. It is quite logical to assume that every person, even if he is a genius, should value the time spent with loved ones. Life is short, and the more precious social experiences we gain, the happier we should be. Don't smart people understand this?
Another scientist, Carol Graham, offers the following explanation. Gifted people with developed intelligence use this very intelligence much more often and actively. They constantly think about their own things, so they do not know how to concentrate on what the interlocutor is saying.
The human mind has evolved, so the smartest representatives of humanity, those who are usually called “new people,” get maximum pleasure from solving the most serious problems. Communication brings them discomfort and makes them bored, while for the vast majority of people everything happens exactly the opposite.
According to Lee and Kanazawa, intellectuals prefer to solve global, serious problems, but they have serious difficulties in ordinary communication. Such people are usually not understood, so they do not expand their circle of contacts, but, on the contrary, narrow it.
The researchers also concluded that smart people find it easier to leave their social environment and change their place of residence. They are not as strongly attached to friends and family and are willing to give up attachment if necessary to achieve their goals.
What do the results of this work give us all? Apparently they make us humble. If your loved one does not strive for communication and avoids it in every possible way, perhaps you just need to stop intruding on him?
What should smart loners do? Probably don't get upset about it. Nature intended it this way - you should be alone.
