1. Introduction

Suicide is a global phenomenon and occurs throughout the lifespan. Close to 800 thousand people die due to suicide every year which is one person every 40 seconds. There are indications that for each adult who died by suicide there may have been more than 20 others attempting suicide [1]. It is, therefore, critical to identify the factors that influence suicidal behavior. This study aimed to predict suicide ideation based on the attentional bias in clinical and non-clinical populations.

2. Methods

Participants were 120 individuals (77 women and 43 men) aged 18-40 years who were purposively selected from among suicide attempters and psychiatric outpatients referred to hospitals and medical centers in Tehran as well as non-clinical subjects divided into three groups of clinical-suicidal (n=40), clinical non-suicidal (n=40) and non-clinical (n=40). The criteria for entering study for non-clinical group was having the General Health Questionnaire score of less than 23 [30]. Suicide Stroop Test was used to measure attentional bias in response to positive emotional, negative emotional and suicide-related stimuli, and Beck Scale for Suicide Ideation [37, 38] was used to measure the suicidal thoughts. Three indices of attentional bias including reaction time, time interference and interference ratio were calculated and the data were analyzed using paired-samples t-test, Pearson correlation coefficient and multivariate regression analysis at the 95% confidence level.

3. Results

The longest reaction time and the highest time interference for suicide-related words were observed in the clinical-suicidal group (32.887±130.76 ms). Regardless of the group type, the fastest and slowest reaction times were related to the positive emotional Stroop (-24.325±151.12 ms) and suicide Stroop (11.58±160.30 ms), respectively. Paired t-test results showed no significant difference in mean reaction time between all types of Stroop tests (positive emotional, negative emotional, and suicide) in comparison to the neutral Stroop (P<0.05). However, at 90% confidence level, the mean reaction time for the positive emotional Stroop in the non-suicidal clinical group (ΔM=59.30 ms, t=-1.71, P=0.09) and the overall reaction time (ΔM=24.32 ms, t=-1.76, P=0.08) were faster than those of the neutral Stroop.

Moreover, 11.8% of the variance in suicide ideation of the non-clinical group was explained by attentional bias in the suicide Stroop (β=0.392), but no other variables had a significant role in explaining changes in suicide ideation after controlling for the role of demographic and general health variables in the non-clinical group (P>0.05). In overall, age (β=-0.225), gender (β=0.223), clinical conditions (β=0.224) and recent suicide attempt (β=0.424) explaining 44% of the variances, were significant determinants of suicide ideation and attentional bias indices failed to play any significant role in predicting suicide ideation (P>0.05) (Table 1).

4. Discussion

The clinical and non-clinical population investigated in this study did not show significant attentional bias in the suicide Stroop; hence, it seems that the incidence of attentional bias towards suicide-related information is not related to clinical conditions. Chung and Jaglic (2016), Richard-Devantoy et al. (2016) and Wilson et al. (2019), reported no significant difference between the reaction times of neutral, positive emotional, negative emotional, and suicide Stroop tests [9-11] which is consistent with the findings of the present study. However, Becker et al. (1999) and William and Bordbent (1986) reported that the reaction time of suicide Stroop in suicide attempters was significantly longer than that of other types of Stroop tests [12, 13]. 

According to the present study, age, gender, clinical status, and past suicidal behaviors were significant predictors of suicide ideation, but the indices of attentional bias towards suicide-related information could not predict suicide ideation. Most of the studies in literature have studied the predictive power of attentional bias in relation to suicide attempt, but regarding the suicide ideation, only a simple relationship between attentional bias and suicide ideation has been reported. Most of these studies have shown that there is no significant correlation between attentional bias in suicide strop and suicide ideation [9, 10], but in other stuides, a weak to moderate correlation between attentional bias and suicide ideation has been reported [12]. 

Ethical Considerations

Compliance with ethical guidelines

All ethical principles were considered in this study. The participants were informed about the study objectives and methods, and signed a written consent form; they were also assured of the confidentiality of their information; Moreover, they were allowed to leave the study at any time, and if desired, the results of the research would be available to them.

Funding

This study did not receive any specific grant from funding agencies in the public, commercial, or non-profit sectors.

Authors contributions

All authors contributed in preparing this article.

Conflicts of interest

The authors declared no conflict of interest.

 

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