title: Understanding the relationship between future thinking and suicide risk
Creators: name: Kose, Gonca
Publisher: name: University of Glasgow
Year: 2024

description: Background: Suicide is a major public health problem since approximately 703, 000 people die by suicide every year worldwide according to World Health Organisation statistics. The role of prospective cognitions on mental health and suicide risk has received increasing recognition by researchers in recent years. However, further research investigating the relationship between individuals’ thoughts about their own future (i.e., Positive Future Thinking; PFT and Negative Future Thinking; NFT) and suicide risk (i.e., with and without a history of suicidal behaviours and/or suicidal thoughts) is still needed.

Aims: The current series of studies, within the context of the Integrated Motivational-Volitional (IMV) model, aimed to explore the relationship between future thinking and suicidal thoughts and/or suicidal behaviours, along with investigations of established risk factors for suicide, such as depression, entrapment, defeat, and death-related mental imagery. To achieve this aim, the current thesis addressed three main research questions: (1) What is the nature of the relationship between future thinking and suicide risk? (2) Does the relationship between future thinking and suicide vary depending on the content of future thoughts and time periods? (3) What is the nature of the relationship between future thinking and suicide risk in the context of different risk factors (e.g., defeat and entrapment) across two groups of participants (i.e., those who have a history of suicidal thoughts and/or suicidal behaviours and those who have no history of suicidal thoughts or suicidal behaviours)?

Methods: The introductory chapter included describing suicide terminology, the scale of suicide, socio-demographic risk factors, the psychology of suicide risk, psychological models of suicide, and the aims, research questions and structure of the current thesis. Then, different methods were employed to address the research questions. First, Chapter 2 presents a systematic review study summarising what is known about future thinking and suicide risk relationship in the literature. To this end, a keyword search of databases (i.e., Ovid databases: Medline, EMBASE, and PsycINFO) was conducted. Research papers for inclusion were restricted to those written in English and which investigated the relationship between future thinking (i.e., PFT and NFT) and suicide risk (i.e., suicidal ideation and suicidal behaviour). Second, in Chapter 3, an online cross-sectional survey study examined the relationship between suicide risk and future thinking with the inclusion of the investigation of other psychological factors, such as depression, defeat, entrapment, repetitive future thinking, and consideration of future consequences. Anonymous data were collected from 409 adults (18+ years) with and without any history of suicidal thoughts and/or suicidal behaviours. Third, Chapter 4 described an experimental study in which two groups of individuals with and without a history of suicidal behaviours and/or suicidal thoughts were compared in terms of positive future thinking abilities (i.e., generating things to look forward to across different time periods) and established psychological markers of suicide risk (e.g., depression, defeat, entrapment, and death-related mental imagery). Finally, Chapter 5 synthesised the main findings from the research conducted within this PhD project and assessed these findings in relation to the research questions, as well as addressing the limitations and implications of this project. It ended by proposing future research directions on the future thinking and suicide risk relationship.

Results: 325 potential research papers were yielded from title and abstract screenings, with 30 studies included in the narrative synthesisincluded in the narrative synthesis. Cross-sectional studies (n=15) in our systematic review study with a total of 3633 participants (2002 women, 1190 men, and 441 gender not reported; 114 hospital controls, 1163 undergraduate students, 1490 community controls, and 866 suicide patients) showed that suicidal individuals have a lack of positive future thinking in the absence of any increase in negative future thinking and they estimate future negative events to be more likely to happen to them and positive future events to be less likely to happen to them compared to controls. Six follow-up studies were included in the systematic review study, comprising a total of 1101 participants (664 female and 437 male participants; 504 admitted to hospitals with minor injuries, 143 undergraduate students, and 454 suicide patients). They yielded some evidence supporting the predictive utility of positive future thoughts on suicide risk over time although a few studies found that not all types of positive future thinking (e.g., intrapersonal positive future thinking) may be protective over time and may even act as a risk factor. The samples in other types of studies in the systematic review study covered a wide range of populations including those with different mental health disorders (e.g., personality disorder and psychosis), as well as those with physical illness (i.e., multiple sclerosis). As for the survey study (N=409), there were 300 participants with a history of suicidal behaviours and/or suicidal thoughts, 98 participants without any history of suicidal thoughts or suicidal behaviours and 11 participants who did not report their suicide status (94 male and 299 female, 6 other and 10 missing). A series of binary logistic regression analyses, univariate and multivariate hierarchical regression analyses, moderation analyses (using the PROCESS macro for SPSS), and a simple mediation analysis (following the PROCESS Macro via the bootstrapping method) were used to test the survey study hypotheses. Although participants with suicidal thoughts and/or suicidal behaviours generated fewer positive future thoughts compared to participants without any suicidal history, this difference was not statistically significant. Participants with past suicidal experiences (i.e., suicidal thoughts and/or suicidal behaviours) reported significantly more negative future thoughts (i.e., interpersonal NFT, intrapersonal NFT, and financial/home NFT) than participants without past suicidal experiences even though there were no significant group differences in terms of achievement, leisure/pleasure, other, and health of others NFT types. For the different time periods, there were no significant group differences for PFT, but for NFTs, the next week, next year, and next 5-10 years were significant predictors of suicidal history, and the most important time period was next NFT over 5-10 years. The strongest measure of future thinking to predict suicide ideation was the Future-oriented Repetitive Thought Scale. For the experimental study (total N=53, mean age=28.42), in the suicidal thoughts and/or suicidal attempts history group, there were 20 females, and 10 males compared to 14 female and nine male participants in the control group (i.e., those with no suicidal thoughts and suicidal attempts history). A series of binary logistic regression analyses, two repeated measures ANOVA, two repeated measures ANCOVA, and an independent samples t-test were performed to test the hypotheses. Participants without any history of suicidal thoughts or suicidal behaviours reported significantly more positive future thoughts (PFT) in comparison to participants with a lifetime history of suicidal thoughts and/or suicidal behaviours. Mean scores for PFT between pre- and post-negative mood induction decreased significantly in both groups; however, this decline was stronger in the participants with a history of suicidal thoughts and/or suicidal behaviours, but only significant when depression and/or suicide ideation were assessed as covariates. Additionally, individuals with a history of suicidal thoughts and/or suicidal behaviours had significantly higher levels of death related mental imagery, depression, entrapment, and defeat than those without a history of suicide.

Conclusion: Despite the heterogeneity across studies (in terms of measures, samples, and methodologies) included in the systematic review study, there was clear evidence that suicidal individuals had a reduced ability to generate positive future thoughts. The results of the survey study indicated that the relationship between future thinking and suicide risk is complicated, and it varies as a function of the content of future thoughts. Nevertheless, future orientation shows promise as a cognitive variable potentially associated with suicide risk, however, its role in suicidality needs to be better understood. Treatments designed to improve thinking in relation to the future (e.g. reducing negative future thoughts and increasing positive future thoughts) may reduce the risk of suicide. As for the experimental study, positive future thinking is affected by a negative mood induction in individuals with and without a history of suicidal thoughts and/or suicidal behaviours, but it is most marked in those with a history of suicidal thoughts and/or suicidal behaviours when depression and suicide ideation are controlled. Several possible explanations for the results are provided, and some future research directions are given across the thesis.