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Journal of Personalized Medicine Aug 2022Dissociative disorders encompass loss of integration in essential functions such as memory, consciousness, perception, motor control, and identity. Nevertheless,... (Review)
Review
BACKGROUND
Dissociative disorders encompass loss of integration in essential functions such as memory, consciousness, perception, motor control, and identity. Nevertheless, neuroimaging studies, albeit scarce, have suggested the existence of particular brain activation patterns in patients belonging to this diagnostic category. The aim of this review is to identify the main functional neuroimaging correlates of dissociative disorders.
METHODS
we searched the PubMed database to identify functional neuroimaging studies conducted on subjects with a diagnosis of a dissociative disorder, following the PRISMA guidelines. In the end, we included 13 studies in this systematic review, conducted on 51 patients with dissociative identity disorder (DID), 28 subjects affected by depersonalization disorder, 24 with dissociative amnesia, and 6 with other or not specified dissociative disorders.
RESULTS
Prefrontal cortex dysfunction seems prominent. In addition, changes in the functional neural network of the caudate are related to alterations of identity state and maintenance of an altered mental status in DID. Another role in DID seems to be played by a dysfunction of the anterior cingulate gyrus. Other regions, including parietal, temporal, and insular cortices, and subcortical areas were reported to be dysfunctional in dissociative disorders.
CONCLUSIONS
Prefrontal dysfunction is frequently reported in dissociative disorders. Functional changes in other cortical and subcortical areas can be correlated with these diagnoses. Further studies are needed to clarify the neurofunctional correlations of each dissociative disorder in affected patients, in order to identify better tailored treatments.
PubMed: 36143190
DOI: 10.3390/jpm12091405 -
Journal of Trauma & Dissociation : the... 2023This systematic review and meta-analysis aimed to investigate the relationship between dissociation and obsessive-compulsive symptoms (OCS) and disorder (OCD).... (Meta-Analysis)
Meta-Analysis Review
This systematic review and meta-analysis aimed to investigate the relationship between dissociation and obsessive-compulsive symptoms (OCS) and disorder (OCD). Specifically, the study aimed to (a) estimate the pooled prevalence of dissociative disorders among individuals with OCD; (b) systematically review the prevalence of OCD among individuals with dissociative disorders; (c) compare the severity of dissociative symptoms between individuals with OCD and non-clinical controls; (d) estimate the association between OCS and dissociative symptoms in the clinical and non-clinical populations. A systematic search was carried out in biomedical databases from inception to January 2022 according to PRISMA guidelines. A total of 41 studies met inclusion criteria ( = 9,438, 34.3% males). The pooled prevalence of dissociative disorders in adult samples with OCD was 8% (95% CI [3, 15], = 5). Studies on adolescent and adult patients with dissociative disorders found that 17-32% reported comorbid OCD, while a prospective study of patients with early-onset dissociative disorders found no evidence of association with OCD. Individuals affected by OCD reported more dissociative symptoms than non-clinical controls ( = .67, 95% CI [.18, 1.16], = 9). A moderate correlation between dissociative symptoms and OCS was detected ( = .43, 95% CI [.36, .51], = 18). Sensitivity analyses showed small/moderate correlations between dissociative experiences and specific types of obsessions and compulsions. Findings suggest that dissociative symptoms are moderately related to OCS in both clinical and non-clinical populations. Interventions aimed to reduce dissociation might improve treatment response of patients suffering from OCD.
Topics: Adult; Male; Adolescent; Humans; Female; Obsessive-Compulsive Disorder; Prospective Studies; Comorbidity; Dissociative Disorders; Prevalence
PubMed: 36820493
DOI: 10.1080/15299732.2023.2181477 -
Cells Feb 2022Ketamine is a rapid-acting antidepressant with proven efficacy as an add-on agent in unipolar and bipolar treatment-resistant depression. Although many studies have been... (Review)
Review
BACKGROUND AND OBJECTIVES
Ketamine is a rapid-acting antidepressant with proven efficacy as an add-on agent in unipolar and bipolar treatment-resistant depression. Although many studies have been published, there is still not enough data on the effect of ketamine in combination with other medications. Particularly interesting is the combination of ketamine and lamotrigine, and its potential role in bipolar depression. The aim of this review was to identify animal and human studies in which ketamine and lamotrigine were used together in order to find out if there is scientific ground for combining ketamine and lamotrigine in the treatment of mood disorders. Directions for future studies are presented.
MATERIALS AND METHODS
PubMed and Web of Science were searched. Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA 2020 methodology was applied.
RESULTS
Seventeen studies were included for review. Animal studies using models of depression suggested a synergistic effect of ketamine and lamotrigine in combination. Studies on healthy humans showed a reduction in ketamine-induced dissociative symptoms with lamotrigine pretreatment. In a study on patients with depression, ketamine and lamotrigine did not have a stronger antidepressant effect than ketamine alone, but in this study only one ketamine infusion was administered. One case series described the antidepressant and anti-suicidal effect of the combination in two bipolar patients. Available clinical studies on patients with mood disorders did not support the hypothesis that lamotrigine reduces ketamine-induced dissociative symptoms.
CONCLUSIONS
The results of the analyzed studies were not sufficient to answer any of the stated questions; however, they allowed us to delineate future research directions. The identified animal studies suggested a possible synergistic antidepressant effect of ketamine and lamotrigine. The available clinical studies were not conclusive. No controlled studies on large groups of bipolar patients with multiple ketamine infusions combined with lamotrigine treatment have been published so far. There is some evidence for the reduction of ketamine's side effects by lamotrigine, and there are reports suggesting that lamotrigine can reduce ketamine craving. More studies with follow-up are needed in order to investigate the ketamine-lamotrigine combination in bipolar patients.
Topics: Animals; Antidepressive Agents; Depression; Humans; Ketamine; Lamotrigine; Psychopharmacology
PubMed: 35203296
DOI: 10.3390/cells11040645 -
BJPsych Open Dec 2022Studies have reported elevated rates of dissociative symptoms and comorbid dissociative disorders in functional neurological disorder (FND); however, a comprehensive... (Review)
Review
BACKGROUND
Studies have reported elevated rates of dissociative symptoms and comorbid dissociative disorders in functional neurological disorder (FND); however, a comprehensive review is lacking.
AIMS
To systematically review the severity of dissociative symptoms and prevalence of comorbid dissociative disorders in FND and summarise their biological and clinical associations.
METHOD
We searched Embase, PsycInfo and MEDLINE up to June 2021, combining terms for FND and dissociation. Studies were eligible if reporting dissociative symptom scores or rates of comorbid dissociative disorder in FND samples. Risk of bias was appraised using modified Newcastle-Ottawa criteria. The findings were synthesised qualitatively and dissociative symptom scores were included in a meta-analysis (PROSPERO CRD42020173263).
RESULTS
Seventy-five studies were eligible (FND = 3940; control = 3073), most commonly prospective case-control studies ( = 54). Dissociative disorders were frequently comorbid in FND. Psychoform dissociation was elevated in FND compared with healthy ( = 0.90, 95% CI 0.66-1.14, = 70%) and neurological controls ( = 0.56, 95% CI 0.19-0.92, = 67%). Greater psychoform dissociation was observed in FND samples with seizure symptoms versus healthy controls ( = 0.94, 95% CI 0.65-1.22, = 42%) and FND samples with motor symptoms ( = 0.40, 95% CI -0.18 to 1.00, = 54%). Somatoform dissociation was elevated in FND versus healthy controls ( = 1.80, 95% CI 1.25-2.34, = 75%). Dissociation in FND was associated with more severe functional symptoms, worse quality of life and brain alterations.
CONCLUSIONS
Our findings highlight the potential clinical utility of assessing patients with FND for dissociative symptomatology. However, fewer studies investigated FND samples with motor symptoms and heterogeneity between studies and risk of bias were high. Rigorous investigation of the prevalence, features and mechanistic relevance of dissociation in FND is needed.
PubMed: 36451595
DOI: 10.1192/bjo.2022.597 -
Psychiatry and Clinical... Sep 2022Reduced memory specificity (i.e., overgeneral memory) is a characteristic of autobiographical memories widely studied in clinical populations, and it is explained by... (Review)
Review
BACKGROUND
Reduced memory specificity (i.e., overgeneral memory) is a characteristic of autobiographical memories widely studied in clinical populations, and it is explained by rumination, functional avoidance, and executive dysfunction. Though the relationship of autobiographical memory specificity with mood and anxiety disorders has been shown, how it relates to dissociation is not well-established. Thus, we aimed to investigate whether dissociative experiences are related to overgeneral memory while considering concurrent depression as a possible confounding factor.
METHODS
We conducted a systematic review in compliance with The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and searched PubMed and Web of Science databases using autobiograph* and dissoc* as our keywords.
RESULTS
Of the 768 studies identified, 9 studies fulfilled the inclusion criteria. A meta-regression analysis was conducted to analyze the relationship between dissociative experiences and depression scores with autobiographical memory test scores. Our research revealed that depression scores, but not dissociative experiences, are significantly related to reduced memory specificity.
CONCLUSION
While the possible overlap between dissociation and depression should be considered in the interpretation of the findings, dissociative experiences do not seem to pose vulnerability for reduced specificity of autobiographical memory. The number of studies on the topic is limited, and they do not have longitudinal follow-ups. The heterogeneous reporting of memory scores and low scores of dissociative experiences in the samples are also limitations of the existing studies.
PubMed: 38766667
DOI: 10.5152/pcp.2022.21285 -
World Journal of Psychiatry Oct 2019Dissociation, which is defined as the failure to associate consciousness, memory, identity, emotion, perception, body representation, motor control, and behavior into an...
BACKGROUND
Dissociation, which is defined as the failure to associate consciousness, memory, identity, emotion, perception, body representation, motor control, and behavior into an integrated whole, has long been assumed to be generated by trauma. If dissociation is a product of trauma exposure, then dissociation would be a major mental health outcome observed in studies of disaster survivors. Although some studies have examined dissociation in disasters, no systematic literature reviews have been conducted to date on the topic.
AIM
To systematically evaluate the literature on the association between disaster and dissociation to determine the prevalence and incidence of dissociation after exposure to disaster and further examine their relationship.
METHODS
EMBASE, Medline, and PsychINFO were searched from inception to January 1, 2019 to identify studies examining dissociative disorders or symptoms related to a disaster in adult or child disaster survivors and disaster responders. Studies of military conflicts and war, articles not in English, and those with samples of 30 or more participants were excluded. Search terms used were "disaster*" and dissociation ("dissociat*," "multiple personality," "fugue," "psychogenic amnesia," "derealization," and "depersonalization"). Reference lists of identified articles were scrutinized to identify studies for additional articles.
RESULTS
The final number of articles in the review was 53, including 36 articles with samples of adults aged 18 and above, 5 of children/adolescents under age 18, and 12 of disaster workers. Included articles studied several types of disasters that occurred between 1989 and 2017, more than one-third (38%) from the United States. Only two studies had a primary aim to investigate dissociation in relation to disaster and none reported data on dissociative disorders. All of the studies used self-report symptom scales; none used structured interviews providing full diagnostic assessment of dissociative disorders or other psychopathology. Several studies mixed exposed and unexposed samples or did not differentiate outcomes between exposure groups. Studies examining associations between dissociation and disaster exposure have been inconclusive. The majority (75%) of the studies compared dissociation with posttraumatic stress, with inconsistent findings. Dissociation was found to be associated with a wide range of other psychiatric disorders, symptoms, and negative emotional, cognitive, and functional states.
CONCLUSION
The studies reviewed had serious methodological limitations including problems with measurement of psychopathology, sampling, and generation of unwarranted conclusions, precluding conclusions that dissociation is an established outcome of disaster.
PubMed: 31649861
DOI: 10.5498/wjp.v9.i6.83 -
Journal of Affective Disorders Sep 2023Patients with Post-traumatic stress disorder (PTSD) exposed to traumatic reminders show hyperreactivity in brain areas (e.g., amygdala) belonging or related to the... (Meta-Analysis)
Meta-Analysis Review
Patients with Post-traumatic stress disorder (PTSD) exposed to traumatic reminders show hyperreactivity in brain areas (e.g., amygdala) belonging or related to the Innate Alarm System (IAS), allowing the rapid processing of salient stimuli. Evidence that IAS is activated by subliminal trauma-reminders could shed a new light on the factors precipitating and perpetuating PTSD symptomatology. Thus, we systematically reviewed studies investigating neuroimaging correlates of subliminal stimulation in PTSD. Twenty-three studies were selected from the MEDLINE and Scopus® databases for a qualitative synthesis, 5 of which allowed a further meta-analysis of fMRI data. The intensity of IAS responses to subliminal trauma-related reminders ranged from a minimum in healthy controls to a maximum in the PTSD patients with the most severe (e.g., dissociative) symptoms or the least responsiveness to treatment. Comparisons with other disorders (e.g., phobias) revealed contrasting results. Our findings demonstrate the hyperactivation of areas belonging or related to IAS in response to unconscious threats that should be integrated in diagnostic as well as in therapeutic protocols.
Topics: Humans; Stress Disorders, Post-Traumatic; Subliminal Stimulation; Brain; Amygdala; Brain Mapping; Magnetic Resonance Imaging
PubMed: 37236272
DOI: 10.1016/j.jad.2023.05.047 -
Consciousness and Cognition Mar 2023Strange face illusions describe a range of visual apparitions that occur when an observer gazes at their image reflected in a mirror or at another person's face in a... (Review)
Review
BACKGROUND
Strange face illusions describe a range of visual apparitions that occur when an observer gazes at their image reflected in a mirror or at another person's face in a dimly lit room. The illusory effects range from mild alterations in colour, or contrast, to the perception of distorted facial features, or new strange faces.The current review critically evaluates studies investigating strange face illusions, their methodological quality, and existing interpretations.
METHOD
Searches conducted using Scopus, PubMed, ScienceDirect and the grey literature until June 2022 identified 21 studies (N = 1,132; healthy participants n = 1,042; clinical participants n = 90) meeting the inclusion criteria (i.e., providing new empirical evidence relating to strange face illusions). The total sample had a mean age of 28.3 years (SD = 10.31) and two thirds (67 %) of participants tested to date are female. Results are reported using the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines. The review was preregistered at the Open Science Framework (OSF: https://osf.io/ek48d).
RESULTS
Pooling data across studies, illusory new strange faces are experienced by 58% (95%CI 48 to 68) of nonclinical participants. Study quality as assessed by the Appraisal Tool for Cross-Sectional Studies (AXIS) revealed that 3/21 (14.28%) studies were rated as high, 9/21 (42.86%) as moderate and 9/21 (42.86%) as low quality. Whilst the items relating specifically to reporting quality scored quite highly, those relating to study design and possible biases were lower and more variable. Overall, study quality accounted for 87% of the variance in reporting rates for strange faces, with higher quality being associated with lower illusion rates. The prevalence of illusions was also significantly greater in samples that were older, had higher proportions of female participants and for the interpersonal dyad (IGDT) compared to the mirror gaze paradigm (MGT). The moderating impact of study quality persisted in a multiple meta-regression involving participant age, paradigm type (IGDT vs MGT) and level of feature distortion. Our review point to the importance of reduced light levels, face stimuli and prolonged eye fixation for strange face illusions to emerge.
CONCLUSION
Strange face illusions reliably occur in both mirror-gazing and interpersonal gazing dyad paradigms. Further research of higher quality is required to establish the prevalence and particularly, the mechanisms underpinning strange face illusions.
Topics: Humans; Female; Adult; Male; Illusions; Cross-Sectional Studies; Face; Fixation, Ocular; Dissociative Disorders
PubMed: 36764163
DOI: 10.1016/j.concog.2023.103480 -
Therapeutic Advances in... 2023The therapeutic potential of subanesthetic doses of ketamine appears promising in unipolar depression; however, its effectiveness in treating bipolar depression (BD)...
BACKGROUND
The therapeutic potential of subanesthetic doses of ketamine appears promising in unipolar depression; however, its effectiveness in treating bipolar depression (BD) remains uncertain.
OBJECTIVE
This systematic review aimed to summarize findings on the use of ketamine for the treatment of BD by assessing its efficacy, safety, and tolerability.
DESIGN
Systematic review.
METHODS
We conducted a systematic review of studies that investigated the use of ketamine for adults with BD. We searched PubMed and Embase for relevant randomized-controlled trials, open-label trials, and retrospective chart analyses published from inception to 13 March 2023.
RESULTS
Eight studies were identified [pooled = 235; mean (SD) age: 45.55 (5.54)]. All participants who received intravenous (IV) ketamine were administered a dose of 0.5-0.75 mg/kg as an adjunctive treatment to a mood-stabilizing agent, whereas participants who received esketamine were administered a dosage ranging from 28 to 84 mg. Flexible dosing was used in real-world analyses. A total of 48% of participants receiving ketamine achieved a response (defined as ⩾50% reduction in baseline depression severity), whereas only 5% achieved a response with a placebo. Real-world studies demonstrated lower rates of response (30%) compared to the average across clinical trials (63%). Reductions in suicidal ideation were noted in some studies, although not all findings were statistically significant. Ketamine and esketamine were well tolerated in most participants; however, six participants (2% of the overall sample pool, 5 receiving ketamine) developed hypomanic/manic symptoms after infusions. Significant dissociative symptoms were observed at the 40-min mark in some trials.
CONCLUSION
Preliminary evidence suggests IV ketamine as being safe and effective for the treatment of BD. Future studies should focus on investigating the effects of repeated acute and maintenance infusions using a randomized study design.
PubMed: 37771417
DOI: 10.1177/20451253231202723 -
Journal of Affective Disorders Jun 2024Electrophysiologic measures provide an opportunity to inform mechanistic models and possibly biomarker prediction of response. Serotonergic psychedelics (SPs) (i.e.,... (Review)
Review
Spectral signatures of psilocybin, lysergic acid diethylamide (LSD) and ketamine in healthy volunteers and persons with major depressive disorder and treatment-resistant depression: A systematic review.
BACKGROUND
Electrophysiologic measures provide an opportunity to inform mechanistic models and possibly biomarker prediction of response. Serotonergic psychedelics (SPs) (i.e., psilocybin, lysergic acid diethylamide (LSD)) and ketamine represent new investigational and established treatments in mood disorders respectively. There is a need to better characterize the mechanism of action of these agents.
METHODS
We conducted a systematic review investigating the spectral signatures of psilocybin, LSD, and ketamine in persons with major depressive disorder (MDD), treatment-resistant depression (TRD), and healthy controls.
RESULTS
Ketamine and SPs are associated with increased theta power in persons with depression. Ketamine and SPs are also associated with decreased spectral power in the alpha, beta and delta bands in healthy controls and persons with depression. When administered with SPs, theta power was increased in persons with MDD when administered with SPs. Ketamine is associated with increased gamma band power in both healthy controls and persons with MDD.
LIMITATIONS
The studies included in our review were heterogeneous in their patient population, exposure, dosing of treatment and devices used to evaluate EEG and MEG signatures. Our results were extracted entirely from persons who were either healthy volunteers or persons with MDD or TRD.
CONCLUSIONS
Extant literature evaluating EEG and MEG spectral signatures indicate that ketamine and SPs have reproducible effects in keeping with disease models of network connectivity. Future research vistas should evaluate whether observed spectral signatures can guide further discovery of therapeutics within the psychedelic and dissociative classes of agents, and its prediction capability in persons treated for depression.
Topics: Humans; Psilocybin; Ketamine; Lysergic Acid Diethylamide; Depressive Disorder, Major; Depression; Healthy Volunteers; Hallucinogens
PubMed: 38570038
DOI: 10.1016/j.jad.2024.03.165