Mind wandering and depression: A status report

Mind-wandering in daily life in depressed individuals: An experience sampling study

BACKGROUND

A diagnostic criterion for Major Depressive Disorder (MDD) is difficulty concentrating and increased distractibility. One form of distraction that occurs in everyday life is mind-wandering. The current study aims to test how individuals with MDD and healthy controls differ in their mind-wandering in everyday life.

METHODS

Adults diagnosed with MDD (n = 53) and healthy controls (n = 53) completed a week of experience sampling, with prompts administered up to eight times per day. At each prompt, participants reported the occurrence and characteristics of their mind-wandering. They also reported levels of momentary negative affect (NA), positive affect (PA), and rumination.

RESULTS

MDD participants reported mind-wandering almost twice as often as healthy control participants. Compared to healthy participants, MDD participants rated their mind-wandering as more negative, but did not differ in terms of temporal orientation. Higher NA and lower PA predicted mind-wandering in the MDD group but not healthy controls, even after controlling for rumination. Time-lagged analyses revealed that current mind-wandering predicted future levels of PA in MDD participants but not in healthy controls; in contrast, current NA and PA did not predict future mind-wandering.

LIMITATIONS

Limitations include our examination of specific forms of mind-wandering (i.e., we did not sample the full spectrum of this construct).

CONCLUSIONS

Individuals with MDD frequently report engaging in mind-wandering in everyday life, and this appears to be coupled with affect. Mind-wandering may have maladaptive effects in MDD and could serve as a target for intervention.

Characterizing human spontaneous thoughts and its application in major depressive disorder

BACKGROUND

Spontaneous thought is a universal, complex, and heterogeneous cognitive activity that significantly impacts mental activity and strongly correlates with mental disorders.

METHODS

Utilizing the think-aloud method, we captured spontaneous thoughts during rest from 38 diagnosed with depression, alongside 36 healthy controls and 137 healthy individuals. Through a comprehensive assessment of various dimensions of thought content, we compared thought content between individuals with depression and healthy controls, and between healthy women and men. Finally, we employed natural language processing (NLP) to develop regression models for multidimensional content assessment and a classification model to differentiate between individuals with and without depression.

RESULTS

Compared to healthy controls, individuals with depression had more internally oriented and less externally oriented spontaneous thoughts. They focused more on themselves and negative things, and less on positive things, experiencing higher levels of negative emotions and lower levels of positive emotions. Besides, we found that compared to healthy men, healthy women's spontaneous thoughts focus more on interoception, the self, past events, and negative events, and they experience higher levels of negative emotions. Meanwhile, we identified the potential application of the think-aloud method to collect spontaneous thoughts and integrate NLP in the field of depression.

CONCLUSIONS

This study offers direct insights into the stream of thought during individuals' resting state, revealing differences between individuals with depression and healthy controls, as well as sex differences in the content of spontaneous thoughts. It enhances our understanding of spontaneous thought and offers a new perspective for preventing, diagnosing, and treating depression.

Personality Moderates Intra-Individual Variability in EEG Microstates and Spontaneous Thoughts

Variability in brain activity that persists after accounting for overt behavioral and physiological states is often considered noise and controlled as a covariate in research. However, studying intra-individual variability in brain function can provide valuable insights into the dynamic nature of the brain. To explore this, we conducted a study on 43 participants analyzing the EEG microstate dynamics and self-reported spontaneous mental activity during five-minute resting-state recordings on two separate days with a twenty days average delay between recordings. Our results showed that the associations between EEG microstates and spontaneous cognition significantly changed from one day to another. Moreover, microstate changes were associated with changes in spontaneous cognition. Specifically, inter-day changes in Verbal thoughts about Others and future Planning were positively related to bottom-up sensory network-related microstate changes and negatively associated with top-down, attention, and salience network-related microstates. In addition, we find that personality traits are related to inter-day changes in microstates and spontaneous thoughts. Specifically, extraversion, neuroticism, agreeableness, and openness to experience moderated the relationship between inter-day changes in EEG microstates and spontaneous thoughts. Our study provides valuable information on the dynamic changes in the EEG microstate-spontaneous cognition organization, which could be essential for developing interventions and treatments for neuropsychiatric disorders.

Recurrent involuntary memories and mind wandering are related but distinct

Spontaneous thought is common in daily life, and includes recurrent involuntary autobiographical memories (IAMs; memories retrieved unintentionally and repetitively) and mind wandering (MW). Both recurrent IAMs and MW are often unintentional or unconstrained, and both predict symptoms of mental health disorders. However, not all MW is unintentional, and not all IAMs are unconstrained. To what extent do recurrent IAMs and MW converge versus diverge? Undergraduates (N = 2,701) completed self-report measures of recurrent IAMs, trait MW, and psychopathology (i.e., PTSD, depression, anxiety). Regressions indicated that recurrent IAMs were significantly associated with spontaneous MW, but not deliberate MW. Further, both spontaneous MW and recurrent IAMs had unique relationships with disorder symptoms. Results suggest that recurrent IAMs are related to MW to the extent that recurrent IAMs are spontaneous. Conversely, recurrent IAMs are distinct from MW to the extent that recurrent IAMs' associations with disorder symptoms could not be solely explained by trait MW (and vice versa). This work highlights related, but distinguishable, forms of spontaneous thought and their transdiagnostic links with psychopathology.

The Future-oriented Repetitive Thought (FoRT) scale: Validation in Chinese samples and application in the schizophrenia spectrum

BACKGROUND

Repetitive thoughts are usually associated with psychopathology. The Future-oriented Repetitive Thought (FoRT) Scale is a measure designed to capture frequency of repetitive thought about positive and negative future events. However, the validity of the scale in Chinese population and its application in the schizophrenia spectrum have not been examined.

METHODS

The current study aimed to examine the psychometric properties of the Chinese version of the FoRT scale and to apply it to the schizophrenia spectrum. In Study 1, three samples (total N = 1875) of university students were recruited for exploratory factor analysis, confirmatory factor analysis, and validity test, respectively. In Study 2, we identified subsamples with high schizotypal traits (N = 89) and low schizotypal traits (N = 89), and recruited 36 inpatients with schizophrenia and 41 matched healthy controls.

RESULTS

The three-factor (pessimistic repetitive future thinking, repetitive thinking about future goals, and positive indulging about the future) structure of the FoRT scale with one item deleted, fitted the Chinese samples. And the scale could distinguish patients with schizophrenia and individuals with high schizotypal traits from controls.

CONCLUSION

These findings support that the Chinese version of the FoRT scale is a valid tool and provide evidence for the potential applications in the schizophrenia spectrum.

Comparison of trait and state mind wandering among schizotypal, subclinically depressed, and control individuals

BACKGROUND

Mind wandering is a common phenomenon in daily life. However, the manifestations and cognitive correlates of mind wandering in different subclinical populations remain unclear. In this study, these aspects were examined in individuals with schizotypal traits and individuals with depressive symptoms, i.e., subclinical populations of patients with schizophrenia and depression.

METHODS

Forty-two individuals with schizotypal traits, 42 individuals with subclinical depression, and 42 controls were recruited to complete a mind wandering thought sampling task (state level) and a mind wandering questionnaire (trait level). Measures of rumination and cognitive functions (attention, inhibition, and working memory) were also completed by participants.

RESULTS

Both subclinical groups exhibited more state and trait mind wandering than did the control group. Furthermore, individuals with schizotypal traits demonstrated more trait mind wandering than individuals with subclinical depression. Rumination, sustained attention, and working memory were associated with mind wandering. In addition, mind wandering in individuals with subclinical depression can be accounted for by rumination or attention, while mind wandering in individuals with high schizotypal traits cannot be accounted for by rumination, attention, or working memory.

CONCLUSIONS

The results suggest that individuals with high schizotypal traits and subclinical depression have different patterns of mind wandering and mechanisms. These findings have implications for understanding the unique profile of mind wandering in subclinical individuals.

EEG Microstates in Mood and Anxiety Disorders: A Meta-analysis

To reduce the psycho-social burden increasing attention has focused on brain abnormalities in the most prevalent and highly co-occurring neuropsychiatric disorders, such as mood and anxiety. However, high inter-study variability in these patients results in inconsistent and contradictory alterations in the fast temporal dynamics of large-scale networks as measured by EEG microstates. Thus, in this meta-analysis, we aim to investigate the consistency of these changes to better understand possible common neuro-dynamical mechanisms of these disorders.In the systematic search, twelve studies investigating EEG microstate changes in participants with mood and anxiety disorders and individuals with subclinical depression were included in this meta-analysis, adding up to 787 participants.The results suggest that EEG microstates consistently discriminate mood and anxiety impairments from the general population in patients and subclinical states. Specifically, we found a small significant effect size for B microstates in patients compared to healthy controls, with larger effect sizes for increased B presence in unmedicated patients with comorbidity. In a subgroup meta-analysis of ten mood disorder studies, microstate D showed a significant effect size for decreased presence. When investigating only the two anxiety disorder studies, we found a significantly small effect size for the increased microstate A and a medium effect size for decreased microstate E (one study). However, more studies are needed to elucidate whether these findings are diagnostic-specific markers.Results are discussed in relation to the functional meaning of microstates and possible contribution to an explanatory mechanism of overlapping symptomatology of mood and anxiety disorders.

The Role of Subgenual Resting-State Connectivity Networks in Predicting Prognosis in Major Depressive Disorder

Background

A seminal study found higher subgenual frontal cortex resting-state connectivity with 2 left ventral frontal regions and the dorsal midbrain to predict better response to psychotherapy versus medication in individuals with treatment-naïve major depressive disorder (MDD). Here, we examined whether these subgenual networks also play a role in the pathophysiology of clinical outcomes in MDD with early treatment resistance in primary care.

Methods

Forty-five people with current MDD who had not responded to ≥2 serotonergic antidepressants (n = 43, meeting predefined functional magnetic resonance imaging minimum quality thresholds) were enrolled and followed over 4 months of standard care. Functional magnetic resonance imaging resting-state connectivity between the preregistered subgenual frontal cortex seed and 3 previously identified left ventromedial, ventrolateral prefrontal/insula, and dorsal midbrain regions was extracted. The clinical outcome was the percentage change on the self-reported 16-item Quick Inventory of Depressive Symptomatology.

Results

We observed a reversal of our preregistered hypothesis in that higher resting-state connectivity between the subgenual cortex and the a priori ventrolateral prefrontal/insula region predicted favorable rather than unfavorable clinical outcomes (rs39 = -0.43, p = .006). This generalized to the sample including participants with suboptimal functional magnetic resonance imaging quality (rs43 = -0.35, p = .02). In contrast, no effects (rs39 = 0.12, rs39 = -0.01) were found for connectivity with the other 2 preregistered regions or in a whole-brain analysis (voxel-based familywise error-corrected p < .05).

Conclusions

Subgenual connectivity with the ventrolateral prefrontal cortex/insula is relevant for subsequent clinical outcomes in current MDD with early treatment resistance. Its positive association with favorable outcomes could be explained primarily by psychosocial rather than the expected pharmacological changes during the follow-up period.

Side effects of monaural beat stimulation during sustained mental work on mind wandering and performance measures

Excessive mind wandering (MW) contributes to the development and maintenance of psychiatric disorders. Previous studies have suggested that auditory beat stimulation may represent a method enabling a reduction of MW. However, little is known about how different auditory stimulation conditions are subjectively perceived and whether this perception is in turn related to changes in subjective states, behavioral measures of attention and MW. In the present study, we therefore investigated MW under auditory beat stimulation and control conditions using experience sampling during a sustained attention to response task (SART). The subjective perception of the stimulation conditions, as well as changes in anxiety, stress and negative mood after versus before stimulation were assessed via visual-analog scales. Results showed that any auditory stimulation applied during the SART was perceived as more distracting, disturbing, uncomfortable and tiring than silence and was related to more pronounced increases of stress and negative mood. Importantly, the perception of the auditory conditions as disturbing was directly correlated with MW propensity. Additionally, distracting, disturbing and uncomfortable perceptions predicted negative mood. In turn, negative mood was inversely correlated with response accuracy for target stimuli, a behavioral indicator of MW. In summary, our data show that MW and attentional performance are affected by the adverse perception of auditory stimulation, and that this influence may be mediated by changes in mood.

Excessive mind wandering, rumination, and mindfulness mediate the relationship between ADHD symptoms and anxiety and depression in adults with ADHD

BACKGROUND

Persistent mind-wandering processes are associated with negative emotions; however, mindful states exhibit an anticorrelation with mind-wandering patterns. The aim of this study is to investigate the mediating role of excessive mind wandering (EMW), rumination, and trait mindfulness between attention-deficit hyperactivity disorder (ADHD) symptoms and the severity of anxiety/depression in adults with ADHD.

METHODS

Medication-free 159 adults diagnosed with ADHD completed a test battery that included a sociodemographic form as well as the Adult ADHD Severity Rating Scale, Hospital Anxiety Depression Scale, Mind Excessively Wandering Scale, Ruminative Response Scale, and Freiburg Mindfulness Inventory after the diagnostic examination according to the Structured Clinical Interview for DSM-5-Clinician Version (SCID-5).

RESULTS

ADHD symptoms exhibited an indirect, but not a direct, association with the severity of anxiety and depression, mediated by increased excessive mind wandering and rumination, as well as decreased trait mindfulness.

LIMITATIONS

This study was carried out within a clinical population using a cross-sectional design. While diagnostic assessments were conducted using SCID-5, psychiatric symptoms were evaluated through self-report measures.

CONCLUSIONS

Coping with EMW and rumination and promoting mindfulness ability may be promising targets in treating comorbid conditions in adults with ADHD. These findings have highlighted the effects of mentation processes on depression and anxiety, which are common comorbidities with ADHD in adults; however, longitudinal studies are needed.

Mind wandering in anxiety disorders: A status report

Many investigations have targeted the subject of worry in anxiety disorders. Worry can be regarded as a subtype of mind wandering (MW), which is undeliberate, perseverative, negatively-valenced, and mainly future-oriented. Nevertheless, until now only a few studies have explored the role of overall MW in the origin and course of anxiety disorders. To foster progress in this field, we briefly describe and discuss relevant studies addressing MW in subjects with anxiety disorders or symptoms or disorders associated with anxiety symptoms. Provisional synthesis suggests that: a) the overall amount of MW is positively correlated with anxiety symptoms; b) MW characteristics reflecting worry and rumination appear to be relevant in anxiety; c) comorbid depressive and ADHD symptoms may contribute to excessive MW in anxiety; d) MW-related therapeutic interventions may be useful as complementary treatments in anxiety disorders. However, more studies related to MW in anxiety disorders or symptoms are necessary to corroborate and extend these initial findings. Such investigations should ideally combine experience sampling with self-rating assessments of both MW and worry/rumination.

Recent advances in the neuroscience of spontaneous and off-task thought: implications for mental health

People spend a remarkable 30-50% of awake life thinking about something other than what they are currently doing. These experiences of being "off-task" can be described as spontaneous thought when mental dynamics are relatively flexible. Here we review recent neuroscience developments in this area and consider implications for mental wellbeing and illness. We provide updated overviews of the roles of the default mode network and large-scale network dynamics, and we discuss emerging candidate mechanisms involving hippocampal memory (sharp-wave ripples, replay) and neuromodulatory (noradrenergic and serotonergic) systems. We explore how distinct brain states can be associated with or give rise to adaptive and maladaptive forms of thought linked to distinguishable mental health outcomes. We conclude by outlining new directions in the neuroscience of spontaneous and off-task thought that may clarify mechanisms, lead to personalized biomarkers, and facilitate therapy developments toward the goals of better understanding and improving mental health.

Individual differences in the frequency of voluntary & involuntary episodic memories, future thoughts, and counterfactual thoughts

Voluntary and involuntary mental time travel can take the form of episodic memory, episodic future thinking, and episodic counterfactual thinking. This study uses an individual-differences approach to understand why people engage in these forms of mental time travel. The individual-differences variables include trait-level personality, boredom proneness, depression, anxiety, stress, emotion regulation, mindfulness, mind-wandering, positive and negative affect, rumination, optimism, thinking styles, and time perspective. Across two studies, our results indicate that individual differences underlie these forms of mental time travel. The most unique, episodic counterfactual thinking, was alone positively correlated with negative emotionality and negatively correlated with optimism. We also observe differences as a function of voluntariness and discuss these findings in relation to the cognitively demanding nature of constructing future and counterfactual thoughts. We discuss the importance of distinguishing voluntary from involuntary thinking and assessing episodic counterfactual thinking in relation to episodic memory and episodic future thinking.

Cognitive Archeology and the Attentional System: An Evolutionary Mismatch for the Genus Homo

Brain evolution is a key topic in evolutionary anthropology. Unfortunately, in this sense the fossil record can usually support limited anatomical and behavioral inferences. Nonetheless, information from fossil species is, in any case, particularly valuable, because it represents the only direct proof of cerebral and behavioral changes throughout the human phylogeny. Recently, archeology and psychology have been integrated in the field of cognitive archeology, which aims to interpret current cognitive models according to the evidence we have on extinct human species. In this article, such evidence is reviewed in order to consider whether and to what extent the archeological record can supply information regarding changes of the attentional system in different taxa of the human genus. In particular, behavioral correlates associated with the fronto-parietal system and working memory are employed to consider recent changes in our species, Homo sapiens, and a mismatch between attentional and visuospatial ability is hypothesized. These two functional systems support present-moment awareness and mind-wandering, respectively, and their evolutionary unbalance can explain a structural sensitivity to psychological distress in our species.

Trait and state effects of different modes of thinking on salivary cortisol in daily life in patients with recurrent major depression and healthy individuals

Habitual modes of thinking such as repetitive negative thinking (RNT), but also momentary cognitive processes such as mindwandering could be vulnerability factors for the course of Major Depressive Disorder (MDD). On the physiological level, cortisol represents an important biological stress marker of the hypothalamic-pituitary-adrenal (HPA) axis. Being a dynamic and non-invasive measure, salivary cortisol can be assessed in daily life via Ambulatory Assessment (AA). So far, consensus exists on a dysregulation of the HPA axis in MDD. However, findings are ambiguous and AA-studies examining both trait and state level effects of cognitive processes on cortisol release in daily life in patients with recurrent major depression (rMDD) and healthy controls (HCs) are lacking. A sample of 119 (n_rMDD=57, n_HCs=62) participants underwent a baseline session, including self-rated questionnaires (RNT, mindfulness) followed by a 5-day AA, where participants indicated the occurrence of mindwandering and levels of mentalshift problems ten times per day via smartphone, and collected saliva cortisol samples five times per day. Via multilevel models, we found habitual RNT, but not mindfulness, to predict higher cortisol levels, with the effects being stronger in rMDD patients. State mindwandering and mentalshift problems predicted increased cortisol 20 min later across groups. State cognitions did not mediate the effects of habitual RNT on cortisol release. Our results suggest independent mechanisms of action for trait and state cognitions on cortisol activity in daily life and indicate a greater physiological vulnerability toward trait RNT and the tendency to experience mentalshift problems in patients with recurrent major depression.

Detecting subtle signs of depression with automated speech analysis in a non-clinical sample

BACKGROUND

Automated speech analysis has gained increasing attention to help diagnosing depression. Most previous studies, however, focused on comparing speech in patients with major depressive disorder to that in healthy volunteers. An alternative may be to associate speech with depressive symptoms in a non-clinical sample as this may help to find early and sensitive markers in those at risk of depression.

METHODS

We included n = 118 healthy young adults (mean age: 23.5 ± 3.7 years; 77% women) and asked them to talk about a positive and a negative event in their life. Then, we assessed the level of depressive symptoms with a self-report questionnaire, with scores ranging from 0-60. We transcribed speech data and extracted acoustic as well as linguistic features. Then, we tested whether individuals below or above the cut-off of clinically relevant depressive symptoms differed in speech features. Next, we predicted whether someone would be below or above that cut-off as well as the individual scores on the depression questionnaire. Since depression is associated with cognitive slowing or attentional deficits, we finally correlated depression scores with performance in the Trail Making Test.

RESULTS

In our sample, n = 93 individuals scored below and n = 25 scored above cut-off for clinically relevant depressive symptoms. Most speech features did not differ significantly between both groups, but individuals above cut-off spoke more than those below that cut-off in the positive and the negative story. In addition, higher depression scores in that group were associated with slower completion time of the Trail Making Test. We were able to predict with 93% accuracy who would be below or above cut-off. In addition, we were able to predict the individual depression scores with low mean absolute error (3.90), with best performance achieved by a support vector machine.

CONCLUSIONS

Our results indicate that even in a sample without a clinical diagnosis of depression, changes in speech relate to higher depression scores. This should be investigated in more detail in the future. In a longitudinal study, it may be tested whether speech features found in our study represent early and sensitive markers for subsequent depression in individuals at risk.

Who Benefits Most? Interactions between Personality Traits and Outcomes of Four Incremental Meditation and Yoga Treatments

Mind–Body Medicine (MBM) includes a broad range of interventions with proven preventive and clinical value, such as yoga and meditation. However, people differ in their preferences and response to different MBM treatments and it remains unclear who benefits most from what type of practice. Thus, finding moderators of treatment outcome seems to be a promising approach. This was the aim of the present study. We conducted a single-case multiple-baseline study investigating the outcomes and moderators of four different MBM treatments. Fifty-seven healthy participants with no prior experience were randomly assigned to three baselines (7, 14, and 21 days) and four eight-week treatments: mantra meditation alone, meditation plus physical yoga, meditation plus ethical education and meditation plus yoga and ethical education. We analysed the data using effect size estimation, multiple regression and cluster analyses. High anxiety, high absorption, low spirituality, low openness and younger age were associated with a range of positive outcomes, such as increased wellbeing or decentering and decreased mind wandering. Receiving ethical education consistently improved wellbeing, while engaging in physical yoga reduced mind wandering. In the cluster analysis, we found that participants with a more maladaptive personality structure enhanced their emotion regulation skills more. Consequently, people do differ in their response to MBM interventions and more vulnerable people, or those high in absorption, seem to benefit more. These findings could support the development of custom-tailored MBM interventions and help clinicians to make scientifically sound recommendations for their patients.

Modulation of Mind Wandering Using Monaural Beat Stimulation in Subjects With High Trait-Level Mind Wandering

Mind wandering (MW) refers to a state when attention shifts from the task at hand or current situation toward thoughts, feelings, and imaginations. This state is often accompanied by a decline in mood, and patients suffering from major depression exhibit more perseverative MW. Hence, although the directionality of the relationship between mood and MW is still under investigation, it may be useful to explore possible avenues to reduce MW. In an earlier pilot study, we investigated MW during auditory beat stimulation in healthy subjects using thought-probes during a sustained attention to response task (SART). We found evidence for reduced MW during monaural 5 Hz beats compared to silence, sine tones, and binaural 5 Hz beats. Moreover, the data tentatively suggested that this reduction was particularly pronounced in subjects with high levels of MW during silence. In the current study, we therefore asked whether MW can be reduced by monaural theta beats in subjects with high trait-levels of MW, as indicated by an online MW questionnaire. Preselected subjects performed a SART task with thought-probes assessing the propensity to mind wander, meta-awareness, and the temporal orientation of MW. Stimulation conditions comprised monaural theta beats, as well as silence (headphones on), and sine tones as control conditions. Our main hypothesis stating that the propensity to mind wander during monaural theta beats is reduced compared to both control conditions was only partly confirmed. Indeed, MW was significantly diminished during exposure to the theta beats compared to sine tones. However, reduced MW during theta beats versus silence was only observed in a subgroup using stricter inclusion criteria. Considering possible reasons for this outcome, our data suggest that the preselection procedure was suboptimal and that beat effects are modulated by the individual responses to auditory stimulation in general.