Scientific background
Suicidal experiences comprise a diverse, and often fluctuating, array of suicidal thoughts, urges, compulsions, images, desires, plans and behaviours. Such experiences usually arise from, and are associated with, immense psychological pain and distress.1–4 Consequently, ameliorating suicidal experiences and preventing suicidal deaths are vital clinical and public health objectives globally.
Prevalence of suicide fatalities, and suicidal thoughts and plans
Annually, around 800,000 lives are lost to suicide worldwide, which corresponds to one person dying by suicide every 40 seconds.5 In 2018, registered suicide fatalities were recorded as 48,344 (i.e. 14.2 deaths per 100,000 population) in the USA6 and as 6507 (i.e. 11.2 deaths per 100,000 population) in the UK.7 In both the USA and the UK, the suicidal death rate has been increasing over time.8,9 Suicide fatalities are less prevalent than suicide plans, which, in turn, are less prevalent than suicidal thoughts. The Adult Psychiatric Morbidity Survey stated that in 2014, in England, UK, 21.6% of individuals had suicidal thoughts, 6.9% attempted suicide and 0.01% died by suicide.10 In the USA, there were 1.4 million suicide attempts in 20176 and 47,000 suicide fatalities.11 Suicidal thoughts, plans and behaviours often, but not always, precede suicide attempts. A recent meta-analysis showed that both suicidal thoughts and suicidal behaviours were predictive of death by suicide with no evidence that suicidal behaviours were a stronger predictor than suicidal thoughts.12 Furthermore, the relationship between ideation and suicidal deaths was found to be stronger in people with a diagnosis of psychosis on the schizophrenia spectrum compared to those with mood disorders.13
Prevalence of suicide fatalities and suicidal thoughts and plans in people with severe mental health problems
People with severe mental health problems, including those with bipolar disorder, personality disorder and those with a diagnosis on the schizophrenia spectrum, have to contend with more frequent and, often, far more severe suicidal experiences, compared to those who do not have such mental health problems.14–17 A large US household survey found that over a 12-month period, people with psychotic symptoms were 5 times more likely to have suicidal thoughts, and 10 times more likely to have made a suicide attempt, compared to people who did not have psychotic symptoms.18 Furthermore, a suicide attempt was reported to be 3.5 times more likely for those who disclosed psychosis together with suicidal thoughts compared to those reporting no suicidal thoughts.18 Perhaps unsurprisingly, in those experiencing non-affective psychoses, or recent-onset psychosis, suicide mortality rates have also been consistently markedly elevated.16 Based on 37 articles with data from 25 countries, death by suicide was found to have a standardised mortality ratio of 12.86 for people with schizophrenia, with all-cause mortality being 2.58 in this population.19 Furthermore, suicide fatalities are increased in those with non-affective psychoses compared to people with other mental health diagnoses. For instance, a recent meta-analysis reported a sixfold increase in suicide fatalities in those with schizophrenia spectrum disorders who had experienced suicidal ideation compared to a 1.5-fold increase in people with affective disorders.13
Understanding the psychological mechanisms underpinning suicidal experiences
It is clear that there is an urgent need to combat a range of suicidal experiences in people with severe mental health problems. In order to do this, it is necessary to understand numerous interacting factors which amplify and accelerate suicidal experiences. Psychological approaches to understanding suicidal thoughts, urges, plans and acts aim to identify the underlying mechanisms by which contributory psychological processes and mechanisms operate at the level of the individual, and in a way which makes sense to people with suicidal experiences. Psychological suicide interventions are most likely to be effective when they are founded upon, and clearly derived from, an understanding of psychological suicide mechanisms.1,4,20,21
Considerable advances have been made in recent years in understanding psychological suicide mechanisms, with putative psychological models becoming more precise, and thus, gaining in the ease with which they can be tested. Recent models include, but are not limited to, the Interpersonal Theory of Suicide,22 the Integrated Motivational-Volitional Model (IMV)23 and the Schematic Appraisals Model of Suicide (SAMS).21,24 Common to the IMV and the SAMS, and resting on a robust empirical foundation derived from working with people with a range of mental health problems, is the centrality of perceptions of defeat, entrapment and hopelessness.25–29 It is well established that perceptions of entrapment, humiliation and powerlessness are often relayed by people with psychotic experiences.30,31 The evidence is growing, which shows that feeling trapped and defeated are also manifest for such individuals when they experience suicidality.32 Perceptions of hopelessness capture a future devoid of satisfaction, goals, values or meaning, in which negative experiences and negative outcomes dominate.33 There is a substantial and enduring literature showing that hopelessness is one of the strongest predictors of suicidal thoughts and behaviours.34–37 Furthermore, high levels of hopelessness are conveyed by people with schizophrenia.36,38–41
The SAMS1,21,42 advances this work further by focusing specifically on personal appraisals of poor emotional processing,43 social and relationship dissatisfaction or breakdown44–46 and difficulties with interpersonal problem-solving.47,48 It is essential to consider associations and interactions between these three types of negative appraisals49,50 and their effect on thoughts and perceptions of being defeated, trapped and hopeless, not only contemporaneously but over time.32,51
Cognitive–behavioural interventions for suicidal experiences
The efficacy and effectiveness of psychological interventions depend on them being grounded on evidence-based, theoretically derived, psychological models of suicidal experiences.4,52–55 Furthermore, it is paramount that interventions should explicitly target different suicidal experiences, such as thoughts, feelings, images, urges, plans and acts.1,56 Cognitive–behavioural therapies (CBTs) have the potential to ameliorate suicidal thoughts and behaviours,56–58 as indicated by a meta-synthesis based on nine reviews.59 Despite this promise, a narrative review highlighted that the extent to which this potential has been investigated in general is lacking, and in people with non-affective psychosis is even more minimal. The review identified only five randomised controlled trials (RCTs) which had recruited people with schizophrenia and assessed suicidal thoughts and acts.60
Cognitive–Behavioural Suicide Prevention for psychosis
One therapy which has focused on reducing both the frequency and severity of suicidal thoughts and acts and their impact is Cognitive–Behavioural Suicide Prevention for psychosis (CBSPp).1,42,52 The therapy is based on the SAMS,21 meaning that the underlying mechanisms were developed in the context of psychosis. Initial pilot RCTs have shown that CBSPp is feasible and acceptable across a range of settings, including in psychiatric inpatient wards,2 that it appeared efficacious in reducing suicidal thoughts and/or acts in people experiencing non-affective psychosis who lived in the community,42,61 and in male prisoners who had severe mental health problems, including psychosis.53
Differences between Cognitive–Behavioural Suicide Prevention for psychosis and traditional, generalised, cognitive–behavioural therapy
Traditional CBT for people with non-affective psychosis has been designed to target specific symptoms of psychosis, such as hallucinations, paranoia and delusions, rather than suicidal experiences specifically.62 No psychological intervention for suicide in those with psychosis to date has been founded on a theory of suicide, nor have any interventions focused on particular psychological processes which underpin suicidal experiences. This means that CBSPp is novel and unique in three ways. First, it has been developed from a psychological model of the mechanisms underlying suicidal thoughts and behaviours which has been generated and supported with empirical evidence in people with severe mental health problems, including psychosis.1,2,21,53,63,64 Second, the intervention directly targets six psychological appraisal processes which trigger, maintain and/or worsen suicidal thoughts and behaviours.65 Third, the intervention has the potential to address both transdiagnostic psychological processes which underpin suicidal experiences, in addition to targeting interactions between specific mental health problems and these psychological appraisal processes.66–68
Overarching goals and overview: Cognitive AppRoaches to coMbatting Suicidality
The overarching goals of the Cognitive AppRoaches to coMbatting Suicidality (CARMS) project65 were to (1) investigate the psychological mechanisms underlying suicidal experiences over time and (2) to test the extent to which a suicide-focused CBT (CBSPp) reduced suicidal experiences using a RCT. The RCT had two arms, which were the control group [treatment as usual (TAU)] and the treatment group, comprising the psychological intervention, CBSPp, plus TAU. There were three assessment time points at baseline, 6 months and 12 months. Participants who had recent suicidal experiences and non-affective psychoses in the last 3 months were recruited. The primary outcome was suicidal thoughts at 6 months following randomisation to the trial.