Suicide was the 18th most prominent cause of death worldwide, accounting for 1.4% of deaths.¹ Suicide is also one of the top 10 causes of death in the general population and the second-highest cause of mortality among people aged 15–34 years old.^2,3,4,5 Suicide affects people of all ages. Suicide is the second leading cause of death for those aged 10–34, the fourth leading cause of death for people aged 35–54 and the eighth leading cause of death for people aged 55–64 in the United States of America.² Every year, over 800 000 people die by suicide around the world, and it is estimated that for every person who dies by suicide, more than 20 others attempt suicide.^3,6 According to statistics, the rate of suicide varies by country and location.⁴

Although suicidal behaviour and non-suicidal self-harm are related terms, the two concepts are different. While suicide is an act of escaping pain and suffering by taking one’s own life, self-injury is a non-suicidal activity used as a coping mechanism. It can provide relief from excruciating pain or emotional numbness and can last for weeks, months or even years.⁷ Non-suicidal self-harm is a behaviour that people engage in when trying to cope with negative feelings or pain. Cutting, burning, scratching, head-banging and punching walls are examples of non-suicidal self-harm. Non-suicidal self-harm involves deliberate activities designed to alleviate emotional discomfort or bad feelings. Suicidal behaviour, on the other hand, entails contemplating, planning, imagining or acting on suicidal ideas or urges. It refers to any action taken by a person to end their life.⁸ Some of the differences are the motivation behind actions, the quantity of damage, the method of self-harm, the frequency of action and so on.⁸

Suicidal behaviour encompasses a variety of behaviours that have the same goal of killing oneself. Suicidal behaviour, however, differs from non-suicidal self-injury, which is a deliberate destruction of one’s own bodily tissue with no lethal intent, although the two behaviours might lead to dying.

Suicidal ideation, planning and attempts are three essential suicidal behaviours. Suicidal ideation occurs when a person considers or plans to commit suicide.³ Suicidal ideation encompasses a wide spectrum of behaviours, from fleeting thoughts to long-term plans. Suicidal ideations, often known as suicidal thoughts or ideas, is a broad term that refers to a variety of thoughts, aspirations and preoccupations with death as well as the inclination or desire to terminate one’s own life.^9,10 Suicidal ideation can range from passive (wanting to die) to active (wanting to kill oneself or thinking of a specific method for doing it).

A suicide plan is defined as ‘a proposed technique of carrying out a design that may result in self-injury; a systematic development of a plan of action that may result in self-injury’.¹¹ Finally, attempting suicide is a planned act of ending one’s life. It is a self-inflicted, possibly harmful behaviour with a nonfatal outcome for which there is evidence of a desire to die (either explicit or implicit).¹¹ Overdosing or ingesting is the most common means of suicide attempt among teenagers, followed by hanging or suffocation and using a sharp object (e.g. cutting).^12,13

Different theories have been used to explain suicidal behaviour. One of them is the ideation-to-action framework proposed by Klonsky and May.¹⁴ According to this model, the development of suicidal ideation and the progression from suicidal ideation to attempts should be seen as distinct processes having distinct predictors and explanations. The ideation-to-action framework sheds more light on what the traditional approaches (psychache, social isolation, escape from aversive self-cognitions, hopelessness and so on) could not explain (i.e. offering different explanations for the development of suicidal ideation and the progression from ideation to attempt). The traditional differs from the ideation-to-action model in that the former treats suicide as a risk and a unitary construct. At the same time, the latter distinguishes ideation predictors from the progression from ideation to behaviour.

The ideation-to-action framework, which specifies: (1) the development of suicidal ideation and (2) the transition from ideation to suicide attempts, is one perspective in the study of suicide. Suicidal ideation, suicide attempts and suicide are all included in this framework,¹⁵ with suicidal ideation being the first phase of suicide. As a result, any self-initiated or committed activities with the aim or expectation of dying, including active or passive self-inflicted acts, are considered suicide.¹⁶

Another significant advancement is a growing collection of research distinguishing between characteristics that predict suicide thoughts and those that predict attempted suicide.¹⁷ According to studies, most suicidal behaviours occur when people are thinking about it.¹⁸ Suicidal behaviour is influenced by various biological, psychological, social, cultural and spiritual variables.

Suicidal ideation is defined as a desire or consideration of suicide.¹⁹ In the literature, there are two types of suicidal ideation (passive and active). Passive suicidal ideation happens when someone aspires to die or believes they might die but has no intention of actually doing so. Active suicidal ideation, on the other hand, refers to the act of thinking about, intending to and planning to commit suicide.¹⁹ Suicidal ideation is a significant risk factor for suicide in adolescents and young people.^20,21 Suicidal ideation has been reported by almost a third of teenagers aged 12–20 years in the United Kingdom.²²

Suicidal behaviour is common among those suffering from mental illnesses such as depression, schizophrenia, bipolar disorder and substance misuse.¹⁹ However, it is not always associated with an underlying disease or a genuine desire to die.²³ Despite the global rise in suicide rates, Rukundo et al.²⁴ found a data vacuum in suicidal behaviour among children and adolescents in poor and middle-income African nations.

Like many other countries, Nigerian research shows an alarming rate of suicide deaths.^25,26 For instance, according to 2019 statistics, there is a 3.5 suicide rate per 100 000 Nigerians.²⁷ Based on an estimated 2021 population of over 211 million people, the death by suicide figure in 2021 was about 7400.²⁷ Most suicide deaths occur in underdeveloped nations such as Nigeria¹⁷ and are often undetected²⁸ and grossly unreported.^6,29,30 According to the World Health Organization’s (WHO) 2018 rating,³ Nigeria has the highest suicide rate in Africa and ranks fifth in the world in terms of acute suicide cases, trailing only South Korea, Russia, India and Japan.³¹

Values of the corrected item-total correlations (point-biserial) indicated discriminations in the items of the RUSS. Values between 0 and 0.19 imply poor discrimination, 0.2 and 0.39 indicate good discrimination, while ≥ 0.4 suggests very good discrimination. As observed in Table 4, the item with a value between 0 and 0.19 in the RUSS is ‘I do not think killing myself would solve my problems’ (0.12). The observed values of the point-biserial suggest that items with values below the very good discrimination should be deleted from the scale, as this could indicate an ambiguous and confusing item to participants.

Table 4 further shows the Cronbach’s alpha and the item-total statistics of the 20-item RUSS. The scale achieved a reliability coefficient of 0.93, a Guttman split-half reliability of r = 0.825 and a Spearman–Brown coefficient of r = 0.828.

This study is a development and validation of the RUSS. The scale measures suicidal behaviours (suicidal ideation, suicide planning and suicide attempts) among the general population. From gap identification to norming, seven steps were used in the development process of the RUSS. Different sources had proposed various steps in the scale development process. For instance, Lynn⁵² proposed a two-stage strategy. The first step included generating an initial pool, and the second stage involved validation (evaluation of the instrument’s item performance). Crocker and Algina⁵³ and Price⁵⁴ both proposed 11 steps; Furr⁵⁵ proposed five steps; Streiner et al.⁵⁶ proposed seven steps, while DeVellis⁵⁷ proposed eight steps. Four main features are common in most of these studies: item generation, item refinement, reliability studies and validity studies. The development process of the RUSS followed these steps.

The DSM-5 and the ICD-10 were used to review clinical aspects of suicidal behaviour (ideation, intent and planning).^44,45,46 The generation of items relating to the agreed themes resulted in 37 items used for scale purification purposes. Because of the RUSS’s ability to measure opinions, beliefs and attitudes, a six-point Likert scale was utilised. In other words, each RUSS item is a declarative statement, hence the decision to employ a Likert answer format.⁵⁷

The RUSS purification was carried out using a combination of reliability analysis and EFA, as proposed by Flynn and Pearcy⁵⁸ and Pecheux and Derbaix.⁵⁹ A team of specialists checked the content validity of the initial items generated by the authors. According to Streiner et al.,⁴⁸ content validity represents current knowledge in the construct of interest. It is also a vital sign of an instrument’s validity and shows how viable and practicable it is.⁶⁰

The development of the RUSS provided a foundation for further investigation of its validity and reliability. Cronbach’s alpha was 0.93, and item-total correlation was 0.13–0.79. This finding implies a good item inter-relatedness, unidimensionality and homogeneity of the construct^61,62 among the Nigerian population. To put it another way, the Cronbach’s alpha, Spearman–Brown coefficient and Guttman split-half coefficient scores were not too high to make some items redundant.^63,64

In conclusion, the high alpha score indicates that the RUSS has a high level of reliability. The RUSS was verified using the concurrent validity approach, as Cronbach and Meehl⁶⁵ advised. Two standardised scales, one each for assessing suicidal ideation and psychological distress in the general population, were positively linked with the RUSS. The RUSS is a suitable measure of suicidal behaviour for adolescents and adults in Nigeria and other climes with similar sociocultural circumstances, based on its EFA and acceptable psychometric qualities.

The RUSS was created by extracting a single-factor scale with 20 items through initial item generation, expert appraisal (face and content validity) of the initial pool of items and EFA for item purification. Internal consistency (reliability coefficient) of the RUSS items is acceptable. The SIS and the GHQ-12 had strong positive correlations with the RUSS, indicating a satisfactory congruent validity coefficient.

Based on the findings of this study, the 19-item RUSS showed good internal consistency and validity scores to measure suicidal behaviour. This analysis indicates that the RUSS is reliable and valid for the Nigerian population. Norms for the group and individual (male and female) samples are indications that the scale is gender-sensitive and can be self-administered both individually and in group studies. Therefore, it is recommended as a diagnostic tool for suicidal behaviour among adolescents and adults in clinical settings. It can also be used to measure suicidality in group research settings to provide information on suicidal behaviour among the general public to enable policymaking in mental healthcare domains. Again, taking into cognisance the Nigerian sociocultural setting in its item generation and development, the RUSS is recommended not only for Nigerian use but also for use in countries with similar sociocultural situations.

This study was conducted in the context of the Nigerian population’s distinct psychosociocultural environment. Without scale revalidation, generalising the findings and using this scale on other populations with different sociocultural traits should be addressed with caution.