The present study aimed to assess the prevalence of suicidal thoughts and suicide attempts in patients with MS and determine the predictive clinical and demographic factors in this regard. In line with previous studies (
6,
11-
13), our findings indicated that 30% of the patients have suicidal thoughts, which resulted in suicide attempts in 8.4%. Given that the prevalence of suicide is 10 per 100,000 in the general Iranian population (
24), the results of the present study were indicative of the significantly higher prevalence rate of suicidal ideation and suicide attempts in MS patients.
The results of the present study showed no significant correlations between age, gender, early disease symptoms, presentation frequency, attempted suicide before MS diagnosis, and the 100-meter walk test with suicidal ideation and suicide attempts. In other words, none of these factors could explain suicidal thoughts and suicide attempts in patients with MS. Contrary to the results obtained by Pompili et al. (
2), which indicated a correlation between disability and suicide in patients with MS, the lack of significance of the 100-meter walk test in our study showed that poorer physical performance due to muscular dystrophy has no effects on increased suicidal thoughts and suicide attempts. Furthermore, lack of significant differences between the patients with and without suicidal ideation and suicide attempts in terms of attempted suicide before disease diagnosis suggests that suicide attempts in MS patients may be due to the disease or factors such as depression. Our findings also demonstrated that the frequency of disease manifestations and presentations did not differ significantly between the patients with and without suicidal thoughts and suicide attempts. However, suicidal thoughts and suicide attempts may be influenced by the severity and speed of symptom progression and disability in MS patients. Further longitudinal studies are required to obtain more accurate results in this regard.
According to the results of the present study, the illiterate MS patients with higher levels of depression were at a significantly higher risk of suicidal thoughts and suicide attempts, which is consistent with previous studies (
2,
12,
13,
15). Our findings regarding suicide attempts are also in line with the current literature (
2,
12,
16,
17), indicating that older age upon the initial disease diagnosis and being a housewife/unemployed significantly decreased the risk of suicide attempts, while increasing comorbidities and suicidal thoughts, leading to a significantly higher risk of suicide attempts (
2,
6,
12,
13,
15,
25).
Illiteracy is a contributing factor to suicidal thoughts and suicide attempts in MS patients since they tend to have a limited knowledge of the disease consequences and cannot independently read books, articles, and websites to find more information. On the other hand, health professionals in Iran provide patients with insufficient information about the consequences and management of the disease. This issue could lead to the confusion of patients, thereby making them feel they have limited control over the disease; consequently, lack of perceived control increases the risk of suicide (
25).
Regarding the housewives and unemployed patients in the current research, it could be stated that this group of patients spend a great amount of time at home and are less involved with workplace challenges, are more related to other family members, and receive physical and psychological support; family support could effectively decrease suicidal tendencies (
26).
As mentioned earlier, depression is highly common among MS patients and is a major trigger of suicidal thoughts and suicide attempts. Depression may also increase the disability of MS patients due to decreased functional ability (
27). Depression directly and indirectly affects the outcome of individuals. According to Feinstein (
13), approximately 29% of patients think about suicide, and severe depression could accurately predict 85% of suicide cases. Although the cause of the high rate of depressive symptoms in MS patients remains unknown, it is assumed that this issue stems from the biological changes in the brain, as well as the psychosocial stress stimulators and disabilities associated with chronic diseases (
27). In MS, demyelination occurs in a part of the brain that controls feelings, thereby leading to the disruption of the treatment process, unpredictability of the disease attacks, reduced ability, and other complications (e.g., job loss). On the other hand, the adverse effects of the medications used in MS treatment could gradually cause depression in the patients (
28). However, the risk factors for depression and suicide remain unclear in these patients.
According to the results of the present study, initial disease diagnosis at a younger age and more comorbidities also contributed to suicide attempts in the MS patients. Notably, young age upon the initial diagnosis was considered an independent risk factor (
2,
7), which could be due to the unexpected nature of the disease. Young MS patients often experience short-term physical disability and dependence on wheelchair, as well as anxiety and depression in case of perceived threats (
29), which is associated with the increased risk of suicide.
According to Gaskill et al. (
25), the physical effects of MS increase the risk of suicidal thoughts and behavior. On the other hand, it seems that physical illnesses or other simultaneous psychiatric diseases may make the patients feel that they lack control over their disease (
25). Since they experience more difficulties, they are commonly faced with misinterpretations regarding the nature of their disease (
30). Such examples of these misconceptions are that MS invariably leads to failure, the inability to deal with loneliness and depression, and limited treatment options (
29). These inefficient attitudes toward MS (especially in the presence of comorbidities) may intensify suicidal behavior in the patients.
5.1. Strengths and Limitations
Using standard instruments (e.g., 100-meter walk test) and assessment of comorbidities were the strengths of the present study. Meanwhile, our model could accurately explain 39.1 - 55.4% of the variance of suicidal thoughts and 23.9 - 54.6% of the variance of suicide attempts. The main limitations of our study were using predictive variables to increase the power of the model, small sample size, assessing the age of the patients at the time of suicide attempts based on the patients’ reminders, the lengthy process of the interviews and questionnaire items, and investigating the patients in only one community (west of Iran). Finally, we did not examine the severity of the patients’ disability by the expanded disability status scale and disease type (progressive/recurrent). Considering the possible effects of the mentioned limitations on the findings, it is recommended that further investigations assess these variables.
5.2. Conclusions
This study aimed to evaluate the prevalence of suicidal thoughts and suicide attempts in MS patients and determine the predictive factors of suicidal thoughts and suicide attempts. According to the results, 30% of the patients had suicidal thoughts, and 8.4% had attempted suicide. Illiteracy and depression were significant risk factors for suicidal thoughts and suicide attempts. On the other hand, older age upon the initial diagnosis and being a housewife/unemployed significantly decreased the risk of suicide attempts, while increased comorbidities and suicidal thoughts significantly increased the risk of suicide attempts. Since MS patients are highly prone to suicidal thoughts and even suicide attempts, providing effective training and preventive psychological interventions to high-risk patients, including illiterate patients with challenging jobs, young patients, and patients with comorbidities and depression, is recommended.