The Science of Suicidal Ideation

Suicidal ideation is not a spontaneous behaviour but is instead a complex interplay among biological, psychological, and environmental processes. The following is a discourse about mechanisms for why suicidal ideation exists and how information can be applied to enable individuals, families, and communities to better recognise warning signs and act upon them. By studying mechanisms, we break beyond fear and move towards lifesaving information and compassion.
Serotonin is one of the neurotransmitters regulating mood and, to some extent, impulse control and stress response. Direct findings indicate that a deficiency in serotonin is associated with increased impulsivity, aggression, mood disorders, and an extremely high risk of suicide; for example, low cerebrospinal fluid (CSF) levels of serotonin’s main metabolite predict future suicide attempts with an odds ratio of about 4.6 (Lee & Kim, 2006; Mann, 2013; Purselle & Nemeroff, 2003; Seo, Patrick, & Kennealy, 2008). Dopamine plays a key role in decision-making, motivation, pleasure, and reinforcement as a neurotransmitter (Harvard Health Publishing, 2023; Simply Psychology, 2024). Lower sensitivity to dopamine has been associated with phenomena such as anhedonia and hopelessness, strong predictors of suicidal behaviour (ScienceDaily, 2013). Selective serotonin reuptake inhibitors (SSRIs) typically enhance serotonin balance; however, their variably effective role in alleviating suicidal ideation requires further evidence, with some literature suggesting risks even for young patients (BMJ, 2005; BMJ Open, 2021).
In addition to brain chemistry, there are theoretical constructs in psychology for suicidal ideation as well. The theory known as the Interpersonal Theory of Suicide, developed by Dr. Thomas Joiner, is based on the idea that suicide is caused when unbearable psychological pain exceeds one’s ability to cope with it. The pain is normally paired with a perception of thwarted belongingness (the need to belong has not been satisfied; one finds oneself isolated) and perceived burdensomeness (others are better off without them; they are a burden to family and friends). The theory builds upon this concept and adds a third component — the acquired capability for suicide, which is the ability to become unafraid of death and pain due to having endured experiences so painful that they leave a lasting impact. As research finds, nearly eighty per cent of suicide attempts include some degree of thwarted belongingness and perceived burdensomeness. Fortunately, treatments such as cognitive behavioural therapy (CBT)-based interventions have proven to halve suicidal ideation by helping individuals recognise and deal with these distorted perceptions.
Societal and environmental causes are also significant contributors to suicidal risk. Trauma in early life in the form of neglect and abuse increases suicidal ideation (Laghaei et al., 2023). Social isolation is another significant contributor, as loneliness is associated with a 45% increased risk for suicide (Alothman et al., 2024; Motillon-Toudic et al., 2022). The COVID-19 pandemic raised risks for suicidal ideation as a direct reaction to financial pressure and enforced social isolation. Suicide is a serious issue but is still severely underfunded, as only eight per cent of countries have established nationwide strategies for addressing the crisis (Mudiyanselage et al., 2024).
New avenues for suicide prevention are emerging in the form of technological breakthroughs. Machine learning can accurately predict suicide risk with accuracies ranging from 84% to 92% within one week of assessment, and from 80% to 86% for predicting risk within a two-year timeframe (Al-Remawi et al., 2024). A Japanese trial applied machine learning and identified suicidal cases, leading to a fall in suicides in trial districts by fifteen per cent. However, there are concerns regarding ethics, specifically regarding privacy and bias in AI systems. Applications like Crisis Text Line have already established that interventions based on AI can be fruitful, identifying at-risk messages and reducing response time by forty per cent. Similarly, chatbots based on AI, like Woebot and derived from cognitive behavioural techniques, have been shown to reduce symptoms of depression in just two weeks.
Successful suicide prevention is as much a function of good tools for early identification of risk as good policies and practices for early response. The Columbia-Suicide Severity Rating Scale (C-SSRS) is widely applied and has been proven to have strong predictive capabilities in identifying suicidal ideation and behaviour. The Beck Depression Inventory (BDI-II) is another widely applied measure for depression severity, and the Patient Health Questionnaire (PHQ-9) is a general healthcare routine depression screening measure. Self-assessment tools like the Suicidal Ideation Attributes Scale (SIDAS) allow clients to track trends in indicators over time and to detect emerging patterns indicative of increased susceptibility.
Stronger problem-solving and emotional regulation abilities can greatly reduce suicide risk, as those who possess them are half as likely to attempt suicide. Mindfulness techniques, diary writing, and maintaining good relationships are some of the best resilience-building strategies and are known to foster resilience. The opposite is seen with negative strategies such as withdrawal and substance use, as they heighten distress and suicide risk. Mindfulness-based interventions have been proven to reduce suicidal thoughts in at-risk clients. Even simple interventions like the 5–4–3–2–1 grounding exercise can provide immediate relief as it anchors one in reality by asking them to name five things they can see, four things they can physically touch, three things they can hear, two things they can smell, and one thing they can taste, thereby calming anxiety and intrusive thinking.
Genetics and epigenetics are also involved in suicide susceptibility. A family history of suicide makes someone four times as susceptible to suicidal thoughts. Trauma is known to affect gene expression and thus predispose some towards mental disorders, as research in epigenetics has established. Genetic indicators for suicidal behaviour have been identified in as many as twelve genes, and in the future, this information may be used for targeted preventive interventions (Ceja et al., 2024).
Suicidal risk is also affected by demographic and cultural factors. Suicide is reported to be three times as common in Indigenous cultures as in the general population due to systemic trauma and social oppression. A second vulnerable population is veterans, for whom there are estimated to be seventeen daily suicides among American veterans. Interventions specifically targeted and based on cultural wisdom have had some efficacy in reducing suicide. Māori wellness programs in New Zealand, for example, incorporate Indigenous healing practices and have yielded a twenty per cent decrease in Māori youths’ suicides.
The suicide rates of young people below the age of 25 and adults aged between 25 and 44 years were three times higher than their non-Indigenous counterparts (Australian Institute of Health and Welfare, 2023). Data from Canada similarly showed that 24.3 per 100,000 person-years was the suicide rate for First Nations people, which is almost three times the rate in the non-Indigenous population (Kumar et al., 2019). In the United States, American Indian and Alaska Native populations have shown elevated suicide rates that often exceed those of other racial and ethnic groups. Although specifics may differ, the literature generally identifies Indigenous suicide prevalence as almost always definitively higher, typically three times or more relative to the general population (Pollock et al., 2018).
Understanding suicidal thoughts as a scientific reality is central to effective intervention. By pinpointing biological, psychological, and environmental causes of suicide risk, we can act preventatively as societies and as individuals. The early identification of warning signs with established instruments for screening, the encouragement of resilience-based coping strategies, and the application of innovative technology are sources of optimism. Confronting these issues systemically in the context of policy reform, financial investments in mental health, and culture-sensitive interventions can secure a future in which suicide is averted rather than merely contemplated after the fact.