Subjective experience of thought overactivation in mood disorders: beyond racing and crowded thoughts

Dynamics of spontaneous thoughts: Exploration, attentional profile and the segmentation of the stream of thoughts

For a long time, clinical knowledge and first-person reports have pointed to individual differences in the dynamics of spontaneous thoughts, in particular in the extreme case of psychiatric conditions (e.g. racing thoughts in Attention Deficit / Hyperactivity Disorder, ADHD; rumination in depression). We used a novel procedure to investigate this individual variability by combining verbal fluency tasks and introspective reports of thought content. Our goal was twofold. First, we tested the hypothesis that a greater segmentation of the stream of thoughts would be associated with trait inattention, in line with subjective reports of ADHD patients. Second, we tested whether the segmentation of the stream of thoughts increased with an increased tendency for exploratory behavior, following recent theoretical claims on the mechanisms underpinning the generation of spontaneous thoughts. Our results support both hypotheses, shedding light on the factors contributing to the individual variability in the dynamics of the stream of thought.

Psychopathological Dissection of Bipolar Disorder and ADHD: Focussing on Racing Thoughts and Verbal Fluency

In the present study, we propose a review and a synthesis of the work of our group about the phenomenology and the cognitive mechanisms of racing thoughts in bipolar disorder (BD) and ADHD. Contrary to the mainstream idea according to which racing thoughts are pathognomonic of BD, our work suggests that racing thoughts are enhanced in ADHD compared to hypomanic episodes of BD, whereas in euthymic episodes of BD self-reported racing thoughts are similar to the rates reported by healthy controls. Using verbal fluency tasks, we found many similarities between bipolar and ADHD subjects with one clear difference: lexical search strategy in hypomania is based on phonemic similarities rather than semantic-relatedness. However, this distinction observed in this cognitive task is certainly difficult to grasp during a clinical interview aiming to differentiate mild hypomania from combined ADHD presentation. The main landmark to distinguish them remains the episodic nature of bipolar disorders as opposed to the lifelong presentation of ADHD symptoms, a dichotomous view that is not so clear-cut in clinical practice.

An overactive mind: Investigating racing thoughts in ADHD, hypomania and comorbid ADHD and bipolar disorder via verbal fluency tasks

BACKGROUND

Adults with Attention Deficit Hyperactivity Disorder (ADHD) often report mental restlessness akin to racing thoughts found in hypomanic and mixed episodes of bipolar disorder (BD). Past research has suggested that racing thoughts in BD can be tackled via process-oriented verbal fluency measures. In ADHD, it is still unknown whether racing thoughts is due to comorbid BD, and its neuropsychological underpinnings remain to be investigated. To this aim, this study investigates process-oriented verbal fluency measures in adults with ADHD compared to adults with BD in a hypomanic episode, adults with ADHD + BD and healthy controls.

METHODS

Three verbal fluency tasks, i.e., the free, the letter and the semantic conditions, were administered to 37 adults with ADHD, 25 adults with BD in a hypomanic episode, 22 adults with comorbid ADHD + BD (euthymia) and 31 healthy subjects. Word production, clustering, and switching were analysed in verbal fluency tasks.

RESULTS

Adults with ADHD, ADHD + BD and hypomania showed increased switches in the free verbal fluency task, compared to healthy controls, despite equivalent number of words produced. Unlike the ADHD and ADHD + BD groups, phonological clustering measures in the semantic task were increased in the hypomanic group compared to healthy controls.

LIMITATIONS

BD groups were under medication.

CONCLUSIONS

Semantic overactivation, reflected by increased switches in the unconstrained verbal fluency task, appear to be a common mechanism involved in racing thoughts in both ADHD and BD. By contrast, unusual sounds-based associations are specific of hypomanic speech and might contribute to the distinction trait and state racing thoughts.

Vocalization and physiological hyperarousal in infant-caregiver dyads where the caregiver has elevated anxiety

Co-regulation of physiological arousal within the caregiver-child dyad precedes later self-regulation within the individual. Despite the importance of unimpaired self-regulatory development for later adjustment outcomes, little is understood about how early co-regulatory processes can become dysregulated during early life. Aspects of caregiver behavior, such as patterns of anxious speech, may be one factor influencing infant arousal dysregulation. To address this, we made day-long, naturalistic biobehavioral recordings in home settings in caregiver-infant dyads using wearable autonomic devices and miniature microphones. We examined the association between arousal, vocalization intensity, and caregiver anxiety. We found that moments of high physiological arousal in infants were more likely to be accompanied by high caregiver arousal when caregivers had high self-reported trait anxiety. Anxious caregivers were also more likely to vocalize intensely at states of high arousal and produce intense vocalizations that occurred in clusters. High-intensity vocalizations were associated with more sustained increases in autonomic arousal for both anxious caregivers and their infants. Findings indicate that caregiver vocal behavior differs in anxious parents, cooccurs with dyadic arousal dysregulation, and could contribute to physiological arousal transmission. Implications for caregiver vocalization as an intervention target are discussed.

Neural correlates of semantic ambiguity resolution in paucisymptomatic bipolar disorder patients

In addition to symptoms specifically related to mood dysregulation, patients with bipolar disorder (BD) show frequent alterations in formal thought organization. A disruption in semantic processing, notably in semantic inhibition, is one of the possible mechanisms that might explain this modified organization. However, to date, little is known about these mechanisms and their underlying neural substrates. This study aimed to identify the neural correlates of the semantic inhibition process in BD patients in comparison to healthy controls. Seventeen BD patients and 17 matched controls were recruited and underwent a 3T MRI scan. A semantic ambiguity resolution task was used during the scan to explore semantic inhibition. Whole-brain analyses were conducted on 13 BD patients and 16 controls. When compared to controls, BD patients had stronger activation in the bilateral temporal areas and right middle frontal gyrus, and less activation in the right hippocampus, parahippocampal area, and bilateral precunei. The present study revealed an altered fronto-temporo-parietal semantic inhibition network in BD patients that could reflect compensative mechanisms or modified semantic processing inducing abnormal thought organization, which has a major impact on the occupational and social functioning of the BD population.

Patients' experiences of cognitive functioning in recurrent depression: A qualitative study

WHAT IS KNOWN ON THE SUBJECT?: Recurrent depressive episodes involve significant morbidity, suicide risk and recurrent hospitalizations. In both major depressive disorder and bipolar disorder, there are significant impairments in functioning following resolution of acute symptoms. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: This paper provides an in-depth qualitative understanding of the subjective experience of cognitive impairment following a depressive episode in a recurrent mood disorder. It identifies descriptions of two types of experience (being stuck and being preoccupied with one's thoughts) that led to impairments in concentration, memory, organization and decision-making. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Mental health nurses need to develop an awareness of the impact of cognitive difficulties in the process of recovery from recurrent mood disorders. Mental health nurses need to provide knowledgeable reassurance, information and interventions to people who experience cognitive difficulties to provide a framework of understanding that promotes recovery. ABSTRACT: Introduction People who experience recurrent depressive episodes often have ongoing cognitive problems that impact on their functional recovery. These cognitive difficulties have been identified as impacting on social, interpersonal and occupational functioning and can result in vulnerability to relapse. Aim The aim of this qualitative study was to explore participants' subjective experiences of cognitive impairment after discharge from mental health services following treatment for recurrent depression. Methods The study was designed as a qualitative study in order to best capture participants' subjective experiences. Data were collected by semi-structured interviews and were analysed using a process of thematic analysis. Results Twenty participants took part in this study. All participants described experiences of either 1) "being stuck"; or 2) "being preoccupied with own thoughts"; however, all participants described the experiences in the third theme: "it stops you living to your potential." Implications for practice In order to promote recovery in a meaningful way, mental health nurses need to provide information about and strategies for managing cognitive difficulties associated with recurrent mood disorders.

Racing thoughts revisited: A key dimension of activation in bipolar disorder

BACKGROUND

Racing and crowded thoughts are frequently reported respectively in manic and mixed episodes of bipolar disorder (BD). However, questionnaires assessing this symptom are lacking. Here we aimed to investigate racing thoughts across different mood episodes of BD through a self-report questionnaire that we developed, the 34-item Racing and Crowded Thoughts Questionnaire (RCTQ). In addition to assessing its factor structure and validity, we were interested in the RCTQ's ability to discriminate mixed and non-mixed depression.

METHODS

221 BD patients and 120 controls were clinically assessed via the YMRS (mania) and the QIDS-C16 (depression), then fulfilled the RCTQ, rumination, worry, and anxiety measures. Three depression groups were operationalized according to YMRS scores: YMRS scores 2 > 6 and YMRS scores = 1 or 2, for respectively mixed and non-pure depression, and YMRS = 0 for pure-depression.

RESULTS

Confirmatory factor analysis showed that the three-factor model of the RCTQ yielded the best fit indices, which improved after the removal of redundant items, resulting in a 13-item questionnaire. Hypomanic and anxiety symptoms were the main predictors of scores; rumination was not a significant predictor. RCTQ results were similar between mixed groups and non-pure depression, and both were higher than in pure-depression.

LIMITATIONS

Patients' pharmacological treatment might have influenced the results.

CONCLUSIONS

The 13-item RCTQ captures different facets of racing thoughts heightened in hypomanic and mixed states, but also in depression with subclinical hypomanic/activation symptoms (e.g. non-pure depression characterized by enhanced subjective irritability), suggesting that it is particularly sensitive to activation symptoms in BD, and could become a valuable tool in the follow-up of patients.

Pre-specified Anxiety Predicts Future Decision-Making Performances Under Different Temporally Constrained Conditions

In real-life circumstances, people occasionally require making forced decisions when encountering unpredictable events and situations that yield socially and privately unfavorable consequences. In order to prevent future negative consequences, it is beneficial to successfully predict future decision-making behaviors based on various types of information, including behavioral traits and/or psychological states. For this prospective purpose, the present study used the Iowa Gambling Task, which simulates multiple aspects of real-life decision-making processes, such as choice preference, selection and evaluation of output feedback, and investigated how anxiety profiles predict decision-making performances under conditions with different temporal pressures on task execution. To conduct a temporally causal analysis, we assessed the trait and state anxiety profiles of 33 young participants prior to the task and analyzed their subsequent decision-making performances. We separated two disadvantageous card decks with high rewards and losses into high- and middle-risk decks, and calculated local performance indexes for decision-making immediately after salient penalty events for the high-risk deck in addition to traditional global performance indexes concerning overall trial outcomes such as final winnings and net scores. For global decision-making, higher trait anxiety predicted more risky choices solely in the self-paced condition without temporal pressure. For local decision-making, state anxiety predicted risk-taking performances differently in the self- and forced-paced conditions. In the self-paced condition, higher state anxiety predicted higher risk-avoidance. In the forced-paced condition, higher state anxiety predicted more frequent choices of the middle-risk deck. These findings suggest not only that pre-specified anxiety profiles can effectively predict future decision-making behaviors under different temporal pressures, but also newly indicate that behavioral mechanisms for moderate risk-taking under an emergent condition should be focused on to effectively prevent future unfavorable consequences when actually encountering negative events.

Altered dynamic electroencephalography connectome phase-space features of emotion regulation in social anxiety

Emotion regulation deficits are commonly observed in social anxiety disorder (SAD). We used manifold-learning to learn the phase-space connectome manifold of EEG brain dynamics in twenty SAD participants and twenty healthy controls. The purpose of the present study was to utilize manifold-learning to understand EEG brain dynamics associated with emotion regulation processes. Our emotion regulation task (ERT) contains three conditions: Neutral, Maintain and Reappraise. For all conditions and subjects, EEG connectivity data was converted into series of temporally-consecutive connectomes and aggregated to yield this phase-space manifold. As manifold geodesic distances encode intrinsic geometry, we visualized this space using its geodesic-informed minimum spanning tree and compared neurophysiological dynamics across conditions and groups using the corresponding trajectory length. Results showed that SAD participants had significantly longer trajectory lengths during Neutral and Maintain. Further, trajectory lengths during Reappraise were significantly associated with the habitual use of reappraisal strategies, while Maintain trajectory lengths were significantly associated with the negative affective state during Maintain. In sum, an unsupervised connectome manifold-learning approach can reveal emotion regulation associated phase-space features of brain dynamics.

Measuring racing thoughts in healthy individuals: The Racing and Crowded Thoughts Questionnaire (RCTQ)

Racing thoughts refer to an acceleration and overproduction of thoughts, which have been associated with manic and mixed episodes. Phenomenology distinguishes 'crowded' from 'racing' thoughts, associated with mixed depression and mania, respectively. Recent data suggest racing thoughts might also be present in healthy individuals with sub-affective traits and symptoms. We investigated this assumption, with a 34-item self-rating scale, the Racing and Crowded Thoughts Questionnaire (RCTQ), and evaluated its reliability, factor structure, and concurrent validity. 197 healthy individuals completed the RCTQ, the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego - autoquestionnaire (TEMPS-A), the Beck Depression Inventory (BDI), the Altman Self-Rating Mania scale (ASRM), and the Ruminative Response Scale (RRS). Exploratory factor analysis yielded a three-factor solution, labeled 'thought overactivation', 'burden of thought overactivation', and 'thought overexcitability'. Internal consistency of each of the three subscales of the RCTQ was excellent. The TEMPS-A cyclothymia score was associated with the three factors, suggesting good concurrent validity. The 'thought activation' subscale was selectively associated with current elated mood and included items conveying both the notion of increased amount and velocity of thoughts, whereas the 'burden of thought overactivation' subscale was associated with current low mood. The 'thought overexcitability' subscale included items conveying the notion of distractibility, and was associated with both elated and low mood. Rumination was not a significant predictor of RCTQ subscores. These results suggest that the RCTQ has good psychometric properties. Racing and crowded thoughts, as measured by the RCTQ, are a multi-faceted phenomenon, distinct from rumination, and particularly associated with mood instability even in its milder forms.

Alterations in neural systems mediating cognitive flexibility and inhibition in mood disorders

Impairment in mental flexibility may be a key component contributing to cardinal cognitive symptoms among mood disorders patients, particularly thought control disorders. Impaired ability to switch from one thought to another might reflect difficulties in either generating new mental states, inhibiting previous states, or both. However, the neural underpinnings of impaired cognitive flexibility in mood disorders remain largely unresolved. We compared a group of mood disorders patients (n = 29) and a group of matched healthy subjects (n = 32) on a novel task-switching paradigm involving happy and sad faces, that allowed us to separate generation of a new mental set (Switch Cost) and inhibition of the previous set during switching (Inhibition Cost), using fMRI. Behavioral data showed a larger Switch Cost in patients relative to controls, but the average Inhibition Cost did not differ between groups. At the neural level, a main effect of group was found with stronger activation of the subgenual cingulate cortex in patients. The larger Switch Cost in patients was reflected by a stronger recruitment of brain regions involved in attention and executive control, including the left intraparietal sulcus, precuneus, left inferior fontal gyrus, and right anterior cingulate. Critically, activity in the subgenual cingulate cortex was not downregulated by inhibition in patients relative to controls. In conclusion, mood disorder patients have exaggerated Switch Cost relative to controls, and this deficit in cognitive flexibility is associated with increased activation of the fronto-parietal attention networks, combined with impaired modulation of the subgenual cingulate cortex when inhibition of previous mental states is needed.

[Mixed depression and DSM-5: A critical review]

BACKGROUND

Mixed depression is a depressive syndrome characterized by the presence, along with the typical depressive symptoms of depression, of those of over activation and excitation. If sometimes this activation is expressed by classical hypomanic symptoms, it is often observed by means of more subtle expression: inner tension, crowded thoughts, dramatic expression suffering, and unproductive agitation. It is important to identify mixed depression because such patients are particularly at risk of suicidal behaviors, substance abuse and therapeutic resistance. Even if therapeutic strategies continue to be discussed, treatments should rely on mood stabilizers and antipsychotics instead of antidepressants as in pure depression. Even though the concept of mixed depression has been described for more than twenty years, first by Koukopoulos and then by other authors, it had been little studied, especially because it did not appear in international psychiatric classifications. The DSM-IV supported a very narrow conception of the mixed states because the criteria required simultaneous full manic and full depressive syndromes, corresponding only to some dysphoric manias. The recently published DSM-5 proposes modifications in mood and bipolar disorder classifications, and especially introduces the possibility to specify depressive and manic episodes with "mixed features". To diagnose depression with mixed features, a full depressive syndrome has to be present together most of time with three hypomanic symptoms, except symptoms that are considered as overlapping (that can be observed either in mania or in depression), i.e. agitation, irritability and distractibility.

METHODS

Critical analysis of DSM criteria and review of literature.

RESULTS

We first analyzed the clinical relevance of the definition of depression with mixed features which could correspond to mixed depression. The problem is that the hypomanic symptoms allowed by the manual lead to symptom associations that are rather illogical (as euphoria with depression) or improbable (as increased or excessive involvement in activities that have a high potential for painful consequences). Also, some more specific symptoms that can be observed in mixed depression are not mentioned (such as hypersensitivity to light or noise, absence of motor retardation, dramatic expressivity of suffering). The DSM-5, as did DSM-IV, refers to an understanding of mixed depression as a simple addition of depressive and manic symptoms. The classification does not take into account that the symptoms could be rather different from hypomania, as the expression of an overactive thought in a depressed mind. Secondly, we reviewed cohort studies using the DSM-5 criteria (or similar criteria with the exclusion of overlapping symptoms), and as a consequence of the poorly defined symptoms, we found that the diagnosis of mixed depression according to DSM-5 is almost impossible, either in unipolar or in bipolar depression.

CONCLUSIONS

We think, with others, that the definition of the mixed depression by the DSM-5 is not clinically relevant and misses important information about the concept. Clinicians can be attentive to the identification of mixed character in depression, even if DSM-5 criteria are not fully met. Unfortunately, the DSM-5 definition could undermine research efforts for a better understanding of epidemiology, phenomenology and therapeutics of mixed depression. We propose and discuss alternative solutions for defining mixed depression, such as the absence of exclusion of "overlapping" symptoms, a more insighted phenomenology, or a dimensional approach.

Neural correlates of generation and inhibition of verbal association patterns in mood disorders

OBJECTIVES

Thought disorders such as rumination or flight of ideas are frequent in patients with mood disorders, and not systematically linked to mood state. These symptoms point to anomalies in cognitive processes mediating the generation and control of thoughts; for example, associative thinking and inhibition. However, their neural substrates are not known.

METHOD

To obtain an ecological measure of neural processes underlying the generation and suppression of spontaneous thoughts, we designed a free word association task during fMRI allowing us to explore verbal associative patterns in patients with mood disorders and matched controls. Participants were presented with emotionally negative, positive or neutral words, and asked to produce two words either related or unrelated to these stimuli.

RESULTS

Relative to controls, patients produced a reverse pattern of answer typicality for the related vs unrelated conditions. Controls activated larger semantic and executive control networks, as well as basal ganglia, precuneus and middle frontal gyrus. Unlike controls, patients activated fusiform gyrus, parahippocampal gyrus and medial prefrontal cortex for emotional stimuli.

CONCLUSIONS

Mood disorder patients are impaired in automated associative processes, but prone to produce more unique/personal associations through activation of memory and self-related areas.