Cognitive inflexibility and suicidal ideation: Mediating role of brooding and hopelessness

Abstract

Previous research suggests that cognitive inflexibility prospectively increases vulnerability to suicidal ideation, but the specific cognitive factors that may explain the relation have not been examined empirically. The present study examined the brooding subtype of rumination and hopelessness as potential mediators of the prospective relation between cognitive inflexibility and suicidal ideation. Fifty-six young adults who completed a measure of cognitive inflexibility and suicidal ideation at baseline were followed up 2–3 years later and completed measures of brooding, hopelessness, and suicidal ideation. Cognitive inflexibility at baseline predicted suicidal ideation at follow up, adjusting for baseline ideation. This relation was mediated by brooding but not by hopelessness. However, there was an indirect relation between perseverative errors and suicidal ideation through brooding, followed by hopelessness, such that brooding was associated with greater hopelessness and hopelessness, in turn, was associated with greater suicidal ideation. Cognitive inflexibility may increase vulnerability to suicidal thinking because it is associated with greater brooding rumination, while brooding, in turn, is associated with hopelessness.

Introduction

Emerging adults, or young adults between ages 18 and 29 (Arnett, 2000), have higher rates of suicidal thoughts, suicide planning, and suicide attempts in the United States than older adults (Centers for Disease Control and Prevention, 2011). Accordingly, recent research has focused on determining predictors of suicidal behavior in young adulthood. Various cognitive characteristics, such as ruminative thinking, hopelessness, and poor problem solving, have been identified as risk factors for suicidal ideation and attempts in emerging adults (Smith et al., 2006, Surrence et al., 2009, Sargalska et al., 2011, Linda et al., 2012). However, much of this research is cross-sectional, with few longitudinal studies (e.g., Smith et al., 2006) examining cognitive predictors of suicidal ideation and attempts in emerging adulthood.

Previous evidence suggests that young people may think about and engage in suicidal behavior because they have difficulty generating solutions to problems (Schotte and Clum, 1982, Schotte and Clum, 1987, Dixon et al., 1994). Being unable to engage in problem solving is thought to reflect cognitive inflexibility (Schotte and Clum, 1982). Cognitive inflexibility is associated with maladaptive cognitions such as rumination (Davis and Nolen-Hoeksema, 2000) and has previously been found to predict increases in suicidal ideation at a 6-month follow up among individuals with a suicide attempt history (Miranda et al., 2012). The present longitudinal study sought to examine the mechanisms by which cognitive inflexibility might predict future suicidal ideation. Specifically, we examined levels of the brooding subtype of rumination and hopelessness as possible mediators of the prospective relation between cognitive inflexibility and suicidal ideation in a sample of emerging adults who were followed up over 2–3 years.

Cognitive inflexibility – defined as the inability to change decision-making in response to feedback from the environment (Lezak et al., 2012) – is associated with suicidal ideation and attempts, although evidence of this relation is mixed (see Jollant et al., 2011, for a review). For instance, one study of 25 depressed patients with current suicidal ideation and 28 depressed patients without suicidal ideation found that the patients with current suicidal ideation performed more poorly on tests of executive functioning, including those measuring cognitive flexibility, compared to the patients without suicidal ideation (Marzuk et al., 2005). Another study found that depressed patients with a history of a high-lethality suicide attempt exhibited more cognitive inflexibility as compared to both healthy controls and depressed patients with a history of a low-lethality attempt (McGirr et al., 2012). However, a study that compared seven recent suicide attempters to seven chronic pain patients and seven healthy controls found that suicide attempters showed poorer performance than controls on measures of verbal and design fluency but did not show differences on tests measuring cognitive flexibility (Bartfai et al., 1990). Additionally, a study that compared 20 suicide attempters to 27 psychiatric controls found no differences in cognitive flexibility between the groups (Ellis et al., 1992). More recently, a study that compared 72 depressed suicide attempters, 80 depressed non-attempters, and 56 non-patient controls found that suicide attempters performed more poorly on measures of attention and working memory but found no differences in other measures of executive functioning, including cognitive inflexibility (Keilp et al., 2013). All of these studies included clinical samples but were limited by being cross-sectional. However, a recent study by Miranda et al. (2012) found that cognitive inflexibility prospectively predicted suicidal ideation at 6-month follow up among a non-clinical sample of suicide attempters. However, it did not examine mechanisms that might explain this relation.

The diathesis–stress–hopelessness model of suicidality (Schotte and Clum, 1982, Schotte and Clum, 1987) suggests that hopelessness is a mechanism through which cognitive inflexibility results in suicidal ideation. That is, being cognitively inflexible prevents individuals from engaging in coping responses that facilitate effective problem solving during times of stress, leading to higher degrees of hopelessness and suicidal ideation. Indeed, there is evidence that suicide ideators and attempters are characterized by poor problem-solving skills (Schotte and Clum, 1987). Furthermore, individuals high in hopelessness and suicidal intent have been found to perform more poorly on measures of social problem-solving (Schotte and Clum, 1982), and both social problem-solving deficits and perceived ineffectiveness in problem-solving are associated with higher levels of hopelessness and suicidal ideation (Schotte and Clum, 1982, Dixon et al., 1991, Dixon et al., 1994, Rudd et al., 1994, D'Zurilla et al., 1998).

Rumination – defined as the tendency to focus on one's feelings of depression and on the causes, meanings, and consequences of one's depression (Nolen-Hoeksema, 1991) – has been identified as a predictor of suicidal ideation concurrently (Surrence et al., 2009) and over time (Smith et al., 2006, Miranda and Nolen-Hoeksema, 2007, O'Connor et al., 2007, O'Connor and Noyce, 2008) and as a correlate of suicide attempts (Crane et al., 2007, Surrence et al., 2009; see also Morrison and O'Connor, 2008). Rumination has also been studied in relation to cognitive inflexibility. Davis and Nolen-Hoeksema (2000) found that individuals who scored high on trait rumination showed more cognitive inflexibility, exhibited by greater perseverative errors on the Wisconsin Card Sorting Test (Heaton et al., 1993), compared to individuals who scored low on trait rumination. Furthermore, rumination is associated with poor problem solving (Lyubomirsky and Nolen-Hoeksema, 1995), which is thought to be a consequence of cognitive inflexibility (Clum et al., 1979). Dysphoric individuals induced to ruminate on their mood were found to generate less effective solutions to interpersonal problems compared to dysphoric individuals induced to distract themselves from their negative mood and also compared to non-dysphoric individuals (Lyubomirsky and Nolen-Hoeksema, 1995). Rumination thus seems to interfere with the ability to find solutions to problems (see Williams et al., 2005), and cognitive inflexibility appears to be implicated in ruminative thinking.

Cognitively inflexible individuals may ruminate because of an inability to focus on something other than their own negative emotions, thereby preventing the generation of alternate coping strategies (Davis and Nolen-Hoeksema, 2000, Nolen-Hoeksema et al., 2008). Continued ruminative thinking may, in turn, lead individuals who ruminate to conclude that their circumstances are hopeless (Nolen-Hoeksema et al., 2008). Lam et al. (2003) found that depressed ruminators displayed higher levels of hopelessness than depressed non-ruminators. Smith et al. (2006) found that average hopelessness, measured over time, partially mediated the prospective relation between baseline levels of rumination and the presence of suicidal ideation over 2.5 years, and fully mediated the relation between rumination and duration of suicidal ideation over time among non-depressed college students who were at high versus low cognitive risk for depression. These findings suggested that rumination may contribute to the initiation of suicidal ideation and also to continued suicidal ideation through increased hopelessness. No research of which we are aware has examined whether rumination and hopelessness may explain the relation between cognitive inflexibility and suicidal ideation.

The present longitudinal study sought to extend this previous research by examining whether cognitive inflexibility would prospectively predict suicidal ideation at a 2–3-year follow up point in a sample of emerging adults, through its effects on the brooding subtype of rumination (see below) and on hopelessness. We hypothesized that cognitive inflexibility, measured at baseline, would predict suicidal ideation at 2–3-year follow up, and that this relation would be mediated by brooding rumination and hopelessness.