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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 -
Psychological Medicine Jul 2022The dissociative subtype of post-traumatic stress disorder (PTSD-DS) was introduced in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders... (Meta-Analysis)
Meta-Analysis Review
The dissociative subtype of post-traumatic stress disorder (PTSD-DS) was introduced in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), and is characterised by symptoms of either depersonalisation or derealisation, in addition to a diagnosis of post-traumatic stress disorder (PTSD). This systematic review and meta-analysis sought to estimate the point prevalence of current PTSD-DS, and the extent to which method of assessment, demographic and trauma variables moderate this estimate, across different methods of prevalence estimation. Studies included were identified by searching MEDLINE (EBSCO), PsycInfo, CINAHL, Academic Search Complete and PTSDpubs, yielding 49 studies that met the inclusion criteria ( = 8214 participants). A random-effects meta-analysis estimated the prevalence of PTSD-DS as 38.1% (95% CI 31.5-45.0%) across all samples, 45.5% (95% CI 37.7-53.4%) across all diagnosis-based and clinical cut-off samples, 22.8% (95% CI 14.8-32.0%) across all latent class analysis (LCA) and latent profile analysis (LPA) samples and 48.1% (95% CI 35.0-61.3%) across samples which strictly used the DSM-5 PTSD criteria; all as a proportion of those already with a diagnosis of PTSD. All results were characterised by high levels of heterogeneity, limiting generalisability. Moderator analyses mostly failed to identify sources of heterogeneity. PTSD-DS was more prevalent in children compared to adults, and in diagnosis-based and clinical cut-off samples compared to LCA and LPA samples. Risk of bias was not significantly related to prevalence estimates. The implications of these results are discussed further.
Topics: Adult; Child; Diagnostic and Statistical Manual of Mental Disorders; Dissociative Disorders; Humans; Prevalence; Stress Disorders, Post-Traumatic
PubMed: 35734787
DOI: 10.1017/S0033291722001647 -
Journal of Psychiatric Research Sep 2020There is currently no general agreement on how to best conceptualize dissociative symptoms and whether they share similar neural underpinnings across dissociative... (Review)
Review
INTRODUCTION
There is currently no general agreement on how to best conceptualize dissociative symptoms and whether they share similar neural underpinnings across dissociative disorders. Neuroimaging data could help elucidate these questions.
OBJECTIVES
The objective of this review is to summarize empirical evidence for neural aberrations observed in patients suffering from dissociative symptoms.
METHODS
A systematic literature review was conducted including patient cohorts diagnosed with primary dissociative disorders, post-traumatic stress disorder (PTSD), or borderline personality disorder.
RESULTS
Results from MRI studies reporting structural (gray matter and white matter) and functional (during resting-state and task-related activation) brain aberrations were extracted and integrated. In total, 33 articles were included of which 10 pertained to voxel-based morphology, 2 to diffusion tensor imaging, 10 to resting-state fMRI, and 11 to task-related fMRI. Overall findings indicated aberrations spread across diverse brain regions, especially in the temporal and frontal cortices. Patients with dissociative identity disorder and with dissociative PTSD showed more overlap in brain activation than each group showed with depersonalization/derealization disorder.
CONCLUSION
In conjunction, the results indicate that dissociative processing cannot be localized to a few distinctive brain regions but rather corresponds to differential neural signatures depending on the symptom constellation.
Topics: Brain; Diffusion Tensor Imaging; Dissociative Disorders; Gray Matter; Humans; Magnetic Resonance Imaging; Stress Disorders, Post-Traumatic
PubMed: 32480060
DOI: 10.1016/j.jpsychires.2020.05.006 -
Journal of Trauma & Dissociation : the... 2021: Research on dissociative symptomatology in the context of Posttraumatic Stress Disorder (PTSD) has been gaining traction, with dissociation being studied as a set of...
: Research on dissociative symptomatology in the context of Posttraumatic Stress Disorder (PTSD) has been gaining traction, with dissociation being studied as a set of complex symptoms following trauma exposure and as a specific subtype of PTSD. The aims of this review are to summarize the literature as it stands, examine the efficacy of existing interventions in treating dissociative symptomatology within the context of PTSD, and offer potential suggestions for future research. : A systematic approach was taken to locate empirical studies on PTSD that included dissociation as an outcome in the PubMed, Scopus, and PsycINFO databases. Recent experimental designs with adult subjects (18+ years) in the English language were included, yielding 103 potentially eligible studies. Thirty-three full-text articles were screened with 17 articles meeting criteria for inclusion in the systematic review. : Designs, populations, treatments, and inventories were extremely diverse. Most therapies did not target dissociation specifically, although the results of this review suggest that PTSD patients who experience dissociative symptoms could benefit from trauma-focused treatments, which often significantly reduced dissociative and trauma-related symptoms. : Future work should consider the evaluation of dissociation as a unique outcome to gain understanding about the nature of traumatic stress and to develop treatment options for its many presentations. The current literature displays limited generalizability to the treatment of individuals with high dissociation, which is a line of inquiry that should be explored. More RCTs are needed.
Topics: Adult; Dissociative Disorders; Humans; Stress Disorders, Post-Traumatic
PubMed: 32401657
DOI: 10.1080/15299732.2020.1760410 -
The Australian and New Zealand Journal... Oct 2022Borderline Personality Disorder (BPD) is frequently complicated by the presence of dissociative symptoms. Pathological dissociation is linked with earlier and more... (Review)
Review
BACKGROUND
Borderline Personality Disorder (BPD) is frequently complicated by the presence of dissociative symptoms. Pathological dissociation is linked with earlier and more severe trauma exposure, emotional dysregulation and worse treatment outcomes in Posttraumatic Stress Disorder and Dissociative Disorders, with implications for BPD.
OBJECTIVE
A systematic scoping review was conducted to assess the extent of current literature regarding the impact of dissociation on BPD and to identify knowledge gaps.
METHODS
Four electronic databases (MEDLINE, APA PsycINFO, EMBASE, CINAHL Plus) were searched, and English peer-reviewed studies with adults with BPD were included, following Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) extension for scoping reviews (PRISMA-ScR) 2018 guidelines.
RESULTS
Most of the 70 included studies were observational (98%) with first authors from Germany (59%). Overall, dissociation was associated with increased BPD symptom severity, self-harm and reduced psychotherapy treatment response; findings regarding suicide risk were mixed. Dissociation was associated with working memory and cognitive deficits, decreased pain perception, altered body ownership, no substance abuse or the abuse of sedative substances, increased fantasy proneness, personality fragmentation, fearful attachment, dream anxiety, perceived stress and altered stress responses, increased cumulative body mass index, decreased water consumption, several neurological correlates and changes in gene expression.
CONCLUSION
BPD with significant dissociative symptoms may constitute a more severe and at-risk subgroup of BPD patients. However, there are significant research gaps and methodological issues in the area, including the possibility of unrecognized Dissociative Disorders in BPD study populations confounding results. Further studies are needed to better understand the impact of dissociation on BPD course and treatment, and to clarify the most appropriate assessment tools for clinical practice. In addition, interventional studies are needed to develop dissociation-specific BPD treatments to determine whether targeting dissociation in BPD can improve treatment outcomes.
Topics: Adult; Borderline Personality Disorder; Dissociative Disorders; Humans; Hypnotics and Sedatives; Psychotherapy; Self-Injurious Behavior
PubMed: 35152771
DOI: 10.1177/00048674221077029 -
Journal of Trauma & Dissociation : the... 2024The 11 revision of the International Classification of Diseases (ICD-11) introduced Complex Posttraumatic Stress Disorder (CPTSD) as a sibling disorder to PTSD.... (Review)
Review
The 11 revision of the International Classification of Diseases (ICD-11) introduced Complex Posttraumatic Stress Disorder (CPTSD) as a sibling disorder to PTSD. Dissociative symptoms have been implicated in the severity of ICD-11 CPTSD; however, no reviews have investigated how dissociation has been measured in studies investigating CPTSD, nor the relationship between CPTSD and dissociation. This systematic review aimed to identify measures used to assess dissociative symptoms in studies that have assessed CPTSD according to ICD-11 criteria and to synthesize the relationship between these constructs. PsycINFO, PubMed, Scopus and Web of Science were searched on March 31, 2021. Seventeen articles met inclusion criteria. CPTSD was most frequently measured by a version of the International Trauma Questionnaire. Twelve measures were used to assess for dissociative symptoms, the most common being the Dissociative Symptoms Scale and the Dissociative Experiences Scale. The relationship between CPTSD and dissociative symptoms was moderate-to-strong, but inconsistently reported. Further research is needed to determine the most appropriate measure(s) of dissociation in CPTSD.
Topics: Humans; Stress Disorders, Post-Traumatic; Surveys and Questionnaires; International Classification of Diseases; Dissociative Disorders
PubMed: 38112306
DOI: 10.1080/15299732.2023.2293785 -
Journal of Trauma & Dissociation : the... 2023Depersonalization-Derealization disorder (DDD) is a psychiatric condition characterized by persistent feelings of detachment from one's self and of unreality about the... (Review)
Review
Depersonalization-Derealization disorder (DDD) is a psychiatric condition characterized by persistent feelings of detachment from one's self and of unreality about the outside world. This review aims to examine the prevalence of DDD amongst different populations. A systematic review protocol was developed before literature searching. Original articles were drawn from three electronic databases and included only studies where prevalence rates of DDD were assessed by standardized diagnostic tools. A narrative synthesis was conducted. Twenty-three papers were identified and categorized into three groups of participants: general population, mixed in/outpatient samples, and patients with specific disorders. The prevalence rates ranged from 0% to 1.9% amongst the general population, 5-20% in outpatients and 17.5-41.9% in inpatients. In studies of patients with specific disorders, prevalence rates varied: 1.8-5.9% (substance abuse), 3.3-20.2% (anxiety), 3.7-20.4% (other dissociative disorders), 16.3% (schizophrenia), 17% (borderline personality disorder), ~50% (depression). The highest rates were found in people who experienced interpersonal abuse (25-53.8%). The prevalence rate of DDD is around 1% in the general population, consistent with previous findings. DDD is more prevalent amongst adolescents and young adults as well as in patients with mental disorders. There is also a possible relationship between interpersonal abuse and DDD, which merits further research.
Topics: Adolescent; Young Adult; Humans; Depersonalization; Prevalence; Dissociative Disorders; Substance-Related Disorders
PubMed: 35699456
DOI: 10.1080/15299732.2022.2079796 -
Clinical Psychology & Psychotherapy Mar 2021Dissociation is a debilitating condition often present as comorbidity in patients with eating disorders, but to date only sparse findings are available on this topic.... (Review)
Review
Dissociation is a debilitating condition often present as comorbidity in patients with eating disorders, but to date only sparse findings are available on this topic. Additionally, very little data exist on the classification of dissociation, namely, psychoform and somatoform, in anorexia nervosa (AN). This review aimed to provide an updated view on the literature about dissociation in AN, with a focus on AN subtypes (i.e., restricter and binge-purging) as well as dissociation type (i.e., psychoform and somatoform), when available. We screened 304 studies, and after title and abstract selection and full-text reading, 29 of them were included in this review. Most of the studies investigated psychoform dissociation, whereas just four publications considered somatoform dissociation. Dissociation resulted to be present in AN more than in healthy controls and in individuals with other psychiatric disorders, and it was related mostly to the binge-purging subtype of AN. Moreover, dissociation was linked to traumatic events, self-harm and negative treatment outcomes, especially in patients affected by the binge-purging subtype of AN. However, results on these matters are scarce and partially discordant. The methodological assessment we performed revealed an overall fair quality of the included studies, although several flaws emerged as well. The present review reported on one hand the relevance of dissociation in AN, but on the other hand the need to stimulate the scientific debate on (a) a deeper investigation of somatoform dissociation in AN and (b) the relationship between dissociation and both clinical severity and treatment response/resistance in AN.
Topics: Anorexia Nervosa; Binge-Eating Disorder; Dissociative Disorders; Humans; Somatoform Disorders
PubMed: 32918777
DOI: 10.1002/cpp.2517