The prevalence of loneliness among a representative sample of the Taiwanese general population was 12.6% in this study. Loneliness was found to be correlated with self-rated heath, psychological distress, and suicide risks. Lonely subjects had significantly higher risks in terms of lifetime suicidal ideation, lifetime suicide attempt, and future suicide intention. Overall, two items of suicidality assessment—“alcohol/drug abuse” and “no one trustworthy to talk to”—were the most influential factors for loneliness.
The prevalence of loneliness varied by country and measurement scales. In Germany, the prevalence of loneliness among the public was 10.5% . In Indonesia, self-reported prevalence was 10.6% (all of the time) and 8.0% (sometimes) . Moreover, perceived loneliness in adults was 18% (20.9% among women vs. 15.0% among men) in a UK-based national survey using a screening questionnaire . Although the measurements of loneliness differed between studies, the prevalence rates ranged between 8% and 18% among the general population, which was consistent with our study finding. Another focus of analysis lies in the age groups surveyed in loneliness studies. Previous studies in Taiwan related to loneliness were mostly focused on the elderly [4, 31, 32]. Loneliness prevalence was found to be higher among the elderly than among those under 65 years of age (14.0% vs. 10.7%, respectively) . Elderly loneliness was associated with poor health condition, no work, no spouse, and poor emotional support [31, 32]. Higher stress levels and depressive symptoms were also found to be highly associated with loneliness among Taiwanese elderly people . Future studies should provide more evidence regarding the causality between age and loneliness.
Our findings supported the association between loneliness and a variety of suicide risks, consistent with the findings of a study by Stikley and Koyanagi (2016), which highlighted that a higher level of loneliness was significantly associated with lifetime suicidal ideation (OR = 5.8) and lifetime suicide attempt (OR = 3.5) in the general population . Our study highlighted the fact that loneliness is associated with past, present, and future suicidality, with future suicide intent having the highest odds for loneliness. This finding was supported by the notion that loneliness could predict later suicidal ideation or behavior [18, 33, 34]. In addition, a dose-response association existed between loneliness and suicidality across time [14, 33]. Therefore, the evidence revealed the importance of assessing suicidality among lonely people. Whether in the community or in clinical settings, lonely individuals require sensitivity from healthcare providers so that they can detect their lifetime, current, or future suicidal ideation/suicide attempt at an early stage in order to prevent the increase of suicide risks.
In terms of other suicide risk factors, the study identified two critical factors related to loneliness—“no one trustworthy to talk to” and “alcohol or drug abuse problems.” Lonely participants reported a higher percentage of a lack of trusting relationships than did their non-lonely counterparts. This finding was supported by a UK study that explored the cause of loneliness among 48 economically deprived young adults (18–24 years) and found that many were lonely due to being unable to express themselves or their feelings and discuss their issues. . Further, social support may mediate the relationship between loneliness and suicidal behavior in the general population . Such evidence highlights the role of trusting and supportive relationships for lonely people. Besides, we found that the odds of drug abuse among lonely participants was 4.8-times higher than among non-lonely participants. Previous studies have also shown a correlation between loneliness and substance abuse, especially for lonely people with psychological distress such as depression and anxiety [9, 13]. Another study in Taiwan revealed a similar result, in which loneliness was related to various dimensions of psychological well-being including depressive symptoms, self-efficacy, suicidal thoughts, and alcohol consumption . Therefore, loneliness may also play a role in alcohol consumption [20, 36, 37, 38], which in turn could cause suicidal ideation . This vicious cycle leads to the common condition of loneliness as reflected by the Taiwanese proverb “the more you drink, the lonelier you get.” Therefore, excessive drinking or substance abuse is likely to be a behavioral manifestation of loneliness.
In terms of psychological distress, the study found that insomnia, anxiety, irritability, depression, and inferiority were 4–7 times more common among lonely participants than among non-lonely participants. Previous studies have also pointed out that loneliness is associated with insomnia, which is believed to be caused by the emotional impact of loneliness that is commonly associated with anxiety and depression, affecting daily rest and sleep . In the English Longitudinal Study of Ageing (ELSA), loneliness was found to be associated with more sleep problems and short sleep duration, evidenced by the fact that highly lonely individuals were particularly vulnerable to sleep problems . Thus, the role of insomnia in the trajectory of loneliness cannot be neglected. Promotion of sleep hygiene and treatment of sleep problems early in the assessment of mental health problems such as loneliness may be necessary.
Furthermore, our study highlighted the relatively stronger association between depression and loneliness in comparison with other psychological factors such as anxiety or inferiority, which is supported by other studies [9, 36]. In addition, loneliness could actually predict changes in depressive symptom in longitudinal studies, independent of social network size . Social network can also influence depression through the mediating effect of loneliness . It is clear to summarize that loneliness could be viewed as one of the factors of social network and depression. Research pointed out that personality factors (such as high neuroticism, low extraversion, and low feelings of mastery) might further mediate the association between loneliness and depression, with these traits influencing the sense of loneliness and depression .
Our study had the advantage of using a large representative sample to understand loneliness prevalence in the general public. However, there are some limitations. First, since this was a cross-sectional study, we could not determine the causality. Second, although the prevalence and correlation of loneliness can be understood by using a single-question screening scale, the type or severity of loneliness remains unclear. Third, the study focused on the association between feeling of loneliness, suicidality, and psychological distress. We failed to consider the influence of internal and external environmental or social factors such as family support. These issues must be examined in detail for future surveys of the general population. Moreover, a longitudinal design is recommended for future research to facilitate the understanding of the causal relationship between loneliness and suicidality.
In summary our study implied that about one in ten people in Taiwan experienced feelings of loneliness. Due to its significant association with suicide and mental distress, it is necessary to consider several psychological factors when engaging with lonely people. However, interventions to reduce loneliness are difficult and complex, due to several interacting components (e.g. goals, personnel, activities, resources, and delivery mode), which may interact with features of the local context in which they are applied (including age profile and health status). These characteristics need to be well described, using the body of evidence to identify those that are effective in a particular context and for a specific population. The study implied that addressing loneliness is essential to our mental and physical health, especially within the community. The first step to improve feelings of loneliness and its subsequent psychological effects will be to effectively link community resources and screen individuals’ loneliness status to identify high-risk groups for further intervention [29, 44]. Furthermore, encouraging community participation in social activities can also promote neighborhood ties and increase social connectedness, thus reducing loneliness . The goal of loneliness reduction can be targeted by improving both physical and mental health while also enhancing psychological well-being in the general population [7, 8, 45].