Ruminations, cognitive inflexibility, and their relationship with suicidal ideation in depressive disorders: A neuropsychological approach

INTRODUCTION

Major depressive disorder is a mental disorder characterized by low mood, decreased energy, and loss of interest or pleasure in normally enjoyable activities. This disorder affects an estimated 264 million people and is currently the leading cause of disability.^[1] According to the National Mental Health Survey conducted in India, one in every 20 people aged 18 and up suffers from clinical depression, 51% have some level of suicidality, and 3% have attempted suicide in the previous month.^[2] Suicidal behavior is frequently the result of a person’s perception of an overwhelming situation. It can happen due to a variety of risk factors such as psychological trauma, unemployment, financial crisis, guilt feelings, substance abuse, personality psychopathology, and so on. Ruminative thinking, hopelessness, poor problem-solving, metacognition, and cognitive inflexibility have all been identified as risk factors for suicidal ideation and attempts in young adults.^[3] Cognitive inflexibility is defined as the inability to change decisions in response to environmental feedback.^[4] Depression has been hypothesized being the result of cognitive constriction and problem-solving deficits, which makes a person vulnerable to suicidal ideations. People who are cognitively restrictive, are unable to find effective solutions to stressful situations, which increases the risk of suicidal behavior.^[5] Depressive rumination is defined as a response mode, in which individuals focus on distress symptoms and the possible causes and outcomes of such symptoms repeatedly and passively.^[6] It is consistently reported in depressive disorders and is correlated with the severity of the illness and is an important predictor of suicidal behavior.^[7] Furthermore, rumination has also been studied in relation to cognitive inflexibility. Previously, a study discovered that people with higher trait rumination were more cognitively inflexible and made more perseverative errors on the Wisconsin card sorting test (WCST) than people with low trait rumination.^[6] Furthermore, rumination is linked to poor problem-solving, which is thought to be the result of cognitive inflexibility. Ruminations deplete cognitive resources, making it difficult to complete tasks that require adequate attention and executive functions. Ruminators have difficulty suppressing irrelevant memories or inhibiting prepotent responses, according to research. Rumination causes increased interference from automatic tendencies on tasks such as the Stroop and Eriksen Flanker task, and executive overload may result in poorer performance on these tasks.^[8]

Wells’ metacognitive theory of emotional disorders includes the cognitive-attentional syndrome (CAS). CAS is a set of psychological processes that include repetitive negative thinking (worry and rumination), threat monitoring, and associated disobliging behavioral and cognitive strategies; it is derived from metacognitive beliefs, which can be positive or negative. While most people have brief periods of negative self-appraisal, the prolonged occurrence of negative emotions and negative self-appraisal in some people is due to CAS activation which may further activate syndromal depression.^[9]

There is, however, a need to understand the interactive role of the attentional processes and executive control on cognitive inflexibility and rumination, thereby harboring suicidal thoughts. The primary goal of this study was to better understand the psychological (rumination and cognitive inflexibility) and neuropsychological (selective attention and executive control) correlates of suicidal ideation in unipolar depression patients. We also hypothesized that depressed patients with higher suicidal ideation (DSI) would be more ruminative and cognitively rigid than depressed patients with no suicidal ideation (NSI). Finally, we hypothesized that the DSI group might perform worse on attention and executive functions than the NSI group.

MATERIAL AND METHODS

RESULTS

[Table 1] shows sociodemographic and clinical characteristics of the samples. The samples were predominantly men (62%), married (62%), and Hindu (86%). Mean age of onset was 28.72 ± 7.34 years, the duration of the current episode was 4.74 ± 2.25 months, and samples were having higher proportion of recurrent depressive disorders as the diagnosis (64%).

Correlations of the study variables are presented in [Table 2]. Suicidal ideation was positively correlated with depression and both brooding and reflective rumination styles as expected. Furthermore, suicidal ideation was positively correlated to rumination (total score) and negatively correlated with cognitive flexibility (total score) [Figure 1]. Among the neuropsychological variables, only category completed on WCST was negatively correlated with suicidal ideation (r = −0.28, P = 0.042). No other neuropsychological variables were significantly correlated with suicidal ideation. Stepwise multiple linear regression analysis was conducted to determine the predictors of suicidal ideation in the sample. In step three of regression equation, suicidal ideation accounted for 62.9% variance. The variables main effects of F (1, 49) = 28.63, P < 0.001***, β = 0.39, t (49) = 3.37, P< 0.002** was found with severity of depression, β = 0.48, t (49) = 4.01, P < 0.001*** for rumination and β =−0.25, t (49) = −2.78, P < 0.008** for incongruent reaction time in Eriksen Flankers task.

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Figure 1:

The scatterplot illustrates the positive linear relationship of suicidal ideation and negative linear relationship with cognitive flexibility.

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Finally, we conducted a subanalysis by comparing the psychological and neuropsychological variables between the two groups (DSI and NSI) based on the MSSI cutoff score = 9. Results of independent sample t-tests show significantly higher rumination (t = 5.75, P < 0.001***) and lower cognitive flexibility (t = −2.56, P = 0.014*) in DSI group as compared to NSI group [Figure 2a]. DSI group had significantly higher rates of perseverative errors as compared to NSI on WCST (t = 5.71, P = 0.008**) and significantly higher errors on identifying both congruent and incongruent trials of EFT (t = 2.30, P = 0.026*) [Figure 2b and c]. Other psychological and neuropsychological variables were non-significant.

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Figure 2:

The boxplots shows that comparison of ruminations and cognitive flexibility (a) and errors on neuropsychological tests (b) between DSI and no suicidal ideation (NSI) group. (c) The clustered bar graph of performance on Wisconsin card sorting test between DSI and NSI group. The mean scores of DSI group were higher on the perseverative and EFT errors as compared to NSI group.

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DISCUSSION

The present study aimed to investigate the relationship of suicidal ideation with various psychological and neuropsychological variables in patients with depressive disorders. The study has strengthened the previous research findings which highlighted a linear relationship with ruminations and cognitive flexibility in patients harboring suicidal ideations.^[4,7] Using neuropsychological variables of attentional as well as executive control have provided newer findings to the existing literature.^[19] The findings show that patients with depression who have suicidal ideation are cognitively less flexible, as evidenced by an inability to change decisions in response to feedback from the environment in lines with the previous literature.^[20] The CAS consists of worry, rumination, fixated attention, and unhelpful self-regulatory strategies or coping behaviors and rumination was found to be more for patients of depression with suicidal ideation.^[9,21-23] The domains of depression related items and brooding was significantly high in with higher suicidal ideation. These results are consistent with a prior finding that brooding predicted increases in depression.^[17] Brooding may be associated with increases in thoughts of suicide because it involves attention to painful symptoms of depression and the negative consequences of depression^[24] Moreover, patients of depression without suicidal ideation group took significantly a smaller number of trials to complete WCST categories and they were given a greater number of correct response and conceptual level response than with suicidal ideation group. The preservative errors (number of errors in which a subject continuously responds incorrectly using the same pattern) were higher in the DSI as compared to NSI group. Earlier King et al.^[19] found depressed suicide attempters performed worse with age in terms of mental sequencing and flexibility than depressed non-attempters (Trail Making Test, part B, Time and Sequencing). Interestingly, they found no differences between groups on tests of attention/concentration, verbal or figural fluency, or another test of mental flexibility and abstract reasoning. On the contrary, impaired EF and suicidality are associated with difficulties in decision making^[25] and impulsivity.^[26]

This study also reveals that a significant difference in errors during performance of the Flanker card task in DSI as compared to NSI group. The DSI group performed with a greater number of errors and less reaction time, that is, they quickly responded to the stimulus which amounts to impulsivity being common in those with prominent suicidal ideation.^[26] It appears that rumination magnifies depressive symptoms, suicidal ideation, and likelihood of attempts by keeping the negative cognitions associated with depressed mood. On further, activation of such vicious circle may interfere with effective problem solving by encouraging a passive and pessimistic state. Overall, our study finding provides a framework to the role played by rumination and cognitive inflexibility, further by state-dependent neuropsychological deficits may trigger suicidal ideation and may lead to future attempt.

CONCLUSION AND FUTURE DIRECTIONS

The present study concludes that ruminations and cognitive inflexibility are associated with suicidality in patient with depression. Moreover, state-dependent neuropsychological deficits in attentional and executive control may worsen depression which may predict suicidal ideation. Major limitations of this study are the smaller sample size, correlational study design, predominantly male, which may limit the generalizability. Future studies may focus on the longitudinal studies to assess the trait level presence or absence of these psychological and neuropsychological variables which may relate to suicidal ideation or attempt in patients with depressive disorders.