ABSTRACT
Psilocybin is a classic psychedelic with demonstrated preliminary clinical efficacy in a range of psychiatric disorders. Evaluating the impact of psilocybin on cognitive function is essential to unravel its potential benefits and risks. In this systematic review, we assessed psilocybin's effect on cognitive function through a comprehensive search of electronic databases from inception to January 2024, identifying 20 articles involving 2,959 participants. While 85% of studies were conducted in healthy volunteers, most of these studies (85%) used macrodoses, ranging from 45 µg/kg to 30 mg/70 kg. Various cognitive aspects were evaluated and yielded mixed results. Global cognitive function, and processing speed remained mostly unchanged in healthy individuals; However, a limited number of studies reported improvements in certain areas such as sustained attention, working memory, and executive function especially in patients with treatment-resistant depression (TRD). Emotional processing was positively modified, particularly in TRD patients. Psilocybin was observed to enhance emotional empathy without significantly altering cognitive empathy and social cognition. Cognitive flexibility and creative cognition were noted to initially decline but could potentially improve over time. Additionally, with respect to learning and memory skills, psilocybin showed promise in improving specific memory types such as semantic associations and associative learning, while its effects on episodic and verbal memory have been less pronounced compared to other cognitive enhancers. The observed mixed findings underscore the complexity of psilocybin's cognitive influence. Further research is essential to provide a clearer understanding of psilocybin's impact on cognitive domains and to guide the development of safe and effective interventions.
ABSTRACT
BACKGROUND: A moral injury occurs when a deeply held moral code has been violated, and it can lead to the development of symptoms of posttraumatic stress disorder (PTSD). However, the neural correlates that differentiate moral injury and PTSD remain largely unknown. Intrinsic connectivity networks such as the default mode network (DMN) appear to be altered in people with PTSD who have experienced moral injury. However, brainstem, midbrain and cerebellar systems are rarely integrated into the intrinsic connectivity networks; this is a critical oversight, because these systems display marked differences in people with PTSD and are thought to underlie strong moral emotions such as shame, guilt and betrayal. METHODS: We conducted an independent component analysis on data generated during script-driven memory recall of moral injury in participants with military- or law enforcement-related PTSD (n = 28), participants with civilian-related PTSD (n = 28) and healthy controls exposed to a potentially morally injurious event (n = 18). We conducted group-wise comparisons of functional network connectivity differences across a DMN-correlated independent component, with a particular focus on brainstem, midbrain and cerebellar systems. RESULTS: We found stronger functional network connectivity in the midbrain periaqueductal grey (t 71 = 4.95, p FDR = 0.028, k = 39) and cerebellar lobule IX (t 71 = 4.44, p FDR = 0.046, k = 49) in participants with civilian-related PTSD as compared to healthy controls. We also found a trend toward stronger functional network connectivity in the midbrain periaqueductal grey (t 71 = 4.22, p FDR = 0.076, k = 60) in participants with military- or law enforcement-related PTSD as compared to healthy controls. LIMITATIONS: The significant clusters were large, but resolution is generally lower for subcortical structures. CONCLUSION: In PTSD, the DMN appears to be biased toward lower-level, midbrain systems, which may drive toxic shame and related moral emotions that are common in PTSD, highlighting the depth at which moral injuries are represented neurobiologically.
Subject(s)
Stress Disorders, Post-Traumatic , Brain/diagnostic imaging , Default Mode Network , Humans , Magnetic Resonance Imaging , Mesencephalon/diagnostic imaging , Morals , Stress Disorders, Post-Traumatic/diagnostic imagingABSTRACT
BACKGROUND: Moral injury (MI) is consistently associated with adverse mental health outcomes, including the development of posttraumatic stress disorder (PTSD) and suicidality. METHODS: We investigated neural activation patterns associated with MI event recall using functional magnetic resonance imaging in participants with military and public safety-related PTSD, relative to civilian MI-exposed controls. RESULTS: MI recall in the PTSD as compared to control group was associated with increased neural activation among salience network nodes involved in viscerosensory processing and hyperarousal (right posterior insula, dorsal anterior cingulate cortex; dACC), regions involved in defensive responding (left postcentral gyrus), and areas responsible for top-down cognitive control of emotions (left dorsolateral prefrontal cortex; dlPFC). Within the PTSD group, measures of state and trait shame correlated negatively with activity among default mode network regions associated with self-related processing and moral cognition (dorsomedial prefrontal cortex; dmPFC) and salience network regions associated with viscerosensory processing (left posterior insula), respectively. CONCLUSIONS: These findings suggest that MI event processing is altered in military and public safety-related PTSD, relative to MI-exposed controls. Here, it appears probable that as individuals with PTSD recall their MI event, they experience a surge of blame-related processing of bodily sensations within salience network regions, including the right posterior insula and the dACC, which in turn, prompt regulatory strategies at the level of the left dlPFC aimed at increasing cognitive control and inhibiting emotional affect. These results are consistent with previous findings showing enhanced sensory processing and altered top-down control in PTSD samples during autobiographical memory recall.
Subject(s)
Stress Disorders, Post-Traumatic , Brain/diagnostic imaging , Emotions , Humans , Magnetic Resonance Imaging , Mental Recall , Shame , Stress Disorders, Post-Traumatic/diagnostic imagingABSTRACT
OBJECTIVE: Mental health among military personnel is an important public health priority. It is known that military personnel experience a high prevalence of child maltreatment and deployment-related traumatic events (DRTEs) and both are related to mental health outcomes. However, few, if any, studies have examined the cumulative and interactive effects of child maltreatment and DRTEs on mental health disorders in a sample of active duty service members and military veterans. METHODS: Data were from the Canadian Armed Forces (CAF) Members and Veterans Mental Health Follow-up Survey collected in 2018 (N = 2,941, response rate = 68.7%), a 16-year follow-up survey of CAF Regular Force members interviewed in 2002. Five types of child maltreatment and 10 types of DTREs were assessed for impact on mental health. Mental disorders included past 12-month generalized anxiety disorder (GAD), panic disorder, social phobia, and major depressive episode (MDE). Past 12-month symptoms of posttraumatic stress disorder (PTSD) were also examined. RESULTS: The prevalence of any exposure to child maltreatment and DRTEs was 62.5% and 68.6%, respectively. All types of child maltreatment were associated with increased odds of past 12-month PTSD symptoms and mental disorders with the exception of physical abuse and GAD as well as childhood exposure to intimate partner violence and panic disorder. Cumulative effects of having experienced both child maltreatment and DRTEs increased the odds of past 12-month PTSD symptoms, GAD, social phobia, and MDE. No interaction effects were significant. CONCLUSIONS: The prevalence of a child maltreatment history is high among active Canadian military and veterans. As well, child maltreatment may increase the likelihood of mental disorders across the life span. This may be especially true for individuals who also experience DRTEs. Understanding these relationships may provide insight into developing effective interventions for military personnel and veteran mental health outcomes.
Subject(s)
Child Abuse , Depressive Disorder, Major , Military Personnel , Stress Disorders, Post-Traumatic , Veterans , Canada/epidemiology , Child , Depressive Disorder, Major/epidemiology , Humans , Stress Disorders, Post-Traumatic/epidemiologyABSTRACT
OBJECTIVE: This study describes patterns of distress associated with exposure to potentially morally injurious experiences (PMIEs) in a Canadian military sample. METHOD: Thematic analysis was performed on interviews from PMIE-exposed military members and Veterans. Participants also completed structured diagnostic interviews, and measures of trauma exposure and psychopathology. Multiple regression examined associations among these variables. Information on pharmacological treatment and past diagnoses are reported. RESULTS: Eight qualitative themes were identified: changes in moral attitudes, increased sensitivity and reactivity to moral situations, loss of trust, disruptions in identity, disruptions in spirituality, disruptions in interpersonal relatedness, rumination, and internalizing and externalizing emotions and behaviors. Self-report data revealed that degree of PMIE exposure was meaningfully associated with posttraumatic stress disorder. CONCLUSION: Qualitative but not quantitative findings supported existing models of moral injury (MI). Additional research is needed to examine the impact of PMIE type on mental health, and to test basic assumptions of MI theory.
Subject(s)
Military Personnel , Stress Disorders, Post-Traumatic , Veterans , Canada , Humans , Morals , Stress Disorders, Post-Traumatic/epidemiologyABSTRACT
Post-traumatic stress disorder (PTSD), a diagnosis that may follow the experience of trauma, has multiple symptomatic phenotypes. Generally, individuals with PTSD display symptoms of hyperarousal and of hyperemotionality in the presence of fearful stimuli. A subset of individuals with PTSD; however, elicit dissociative symptomatology (i.e., depersonalization, derealization) in the wake of a perceived threat. This pattern of response characterizes the dissociative subtype of the disorder, which is often associated with emotional numbing and hypoarousal. Both symptomatic phenotypes exhibit attentional threat biases, where threat stimuli are processed preferentially leading to a hypervigilant state that is thought to promote defensive behaviors during threat processing. Accordingly, PTSD and its dissociative subtype are thought to differ in their proclivity to elicit active (i.e., fight, flight) versus passive (i.e., tonic immobility, emotional shutdown) defensive responses, which are characterized by the increased and the decreased expression of the sympathetic nervous system, respectively. Moreover, active and passive defenses are accompanied by primarily endocannabinoid- and opioid-mediated analgesics, respectively. Through critical review of the literature, we apply the defense cascade model to better understand the pathological presentation of defensive responses in PTSD with a focus on the functioning of lower-level midbrain and extended brainstem systems.
Subject(s)
Dissociative Disorders , Periaqueductal Gray/physiopathology , Stress Disorders, Post-Traumatic , Brain/diagnostic imaging , Emotions , Fear , Humans , Magnetic Resonance Imaging , MaleABSTRACT
BACKGROUND: The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition methods have been applied recently to predict many psychiatric disorders, these techniques have not been utilized to predict subtypes of posttraumatic stress disorder (PTSD), including the dissociative subtype of PTSD (PTSD + DS). METHODS: Using Multiclass Gaussian Process Classification within PRoNTo, we examined the classification accuracy of: (i) the mean amplitude of low-frequency fluctuations (mALFF; reflecting spontaneous neural activity during rest); and (ii) seed-based amygdala complex functional connectivity within 181 participants [PTSD (n = 81); PTSD + DS (n = 49); and age-matched healthy trauma-unexposed controls (n = 51)]. We also computed mass-univariate analyses in order to observe regional group differences [false-discovery-rate (FDR)-cluster corrected p < 0.05, k = 20]. RESULTS: We found that extracted features could predict accurately the classification of PTSD, PTSD + DS, and healthy controls, using both resting-state mALFF (91.63% balanced accuracy, p < 0.001) and amygdala complex connectivity maps (85.00% balanced accuracy, p < 0.001). These results were replicated using independent machine learning algorithms/cross-validation procedures. Moreover, areas weighted as being most important for group classification also displayed significant group differences at the univariate level. Here, whereas the PTSD + DS group displayed increased activation within emotion regulation regions, the PTSD group showed increased activation within the amygdala, globus pallidus, and motor/somatosensory regions. CONCLUSION: The current study has significant implications for advancing machine learning applications within the field of psychiatry, as well as for developing objective biomarkers indicative of diagnostic heterogeneity.
Subject(s)
Amygdala/diagnostic imaging , Dissociative Disorders/diagnostic imaging , Machine Learning , Stress Disorders, Post-Traumatic/diagnostic imaging , Adult , Amygdala/physiopathology , Brain Mapping/methods , Case-Control Studies , Dissociative Disorders/physiopathology , Emotions , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Multivariate Analysis , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Rest , Stress Disorders, Post-Traumatic/physiopathology , Stress Disorders, Post-Traumatic/psychology , Young AdultABSTRACT
Post-traumatic stress disorder (PTSD) is one of the common mental disorders in military and veteran populations. Considerable research and clinical opinion has been focused on understanding the relationship between PTSD and military service and the implications for prevention, treatment, and management. This paper examines factors associated with the development of PTSD in this population, considers issues relating to engagement in treatment, and discusses the empirical support for best practice evidence-based treatment. The paper goes on to explore the challenges in those areas, with particular reference to treatment engagement and barriers to care, as well as treatment non-response. The final section addresses innovative solutions to these challenges through improvements in agreed terminology and definitions, strategies to increase engagement, early identification approaches, understanding predictors of treatment outcome, and innovations in treatment. Treatment innovations include enhancing existing treatments, emerging non-trauma-focused interventions, novel pharmacotherapy, personalized medicine approaches, advancing functional outcomes, family intervention and support, and attention to physical health.
Subject(s)
Evidence-Based Practice , Military Personnel/psychology , Stress Disorders, Post-Traumatic/therapy , Veterans/psychology , HumansABSTRACT
Posttraumatic stress disorder (PTSD) has been associated with a disturbance in neural intrinsic connectivity networks (ICN), including the central executive network (CEN), default mode network (DMN), and salience network (SN). Here, we conducted a preliminary investigation examining potential changes in ICN recruitment as a function of real-time fMRI neurofeedback (rt-fMRI-NFB) during symptom provocation where we targeted the downregulation of neural response within the amygdala-a key region-of-interest in PTSD neuropathophysiology. Patients with PTSD (n = 14) completed three sessions of rt-fMRI-NFB with the following conditions: (a) regulate: decrease activation in the amygdala while processing personalized trauma words; (b) view: process trauma words while not attempting to regulate the amygdala; and (c) neutral: process neutral words. We found that recruitment of the left CEN increased over neurofeedback runs during the regulate condition, a finding supported by increased dlPFC activation during the regulate as compared to the view condition. In contrast, DMN task-negative recruitment was stable during neurofeedback runs, albeit was the highest during view conditions and increased (normalized) during rest periods. Critically, SN recruitment was high for both the regulate and the view conditions, a finding potentially indicative of CEN modality switching, adaptive learning, and increasing threat/defense processing in PTSD. In conclusion, this study provides provocative, preliminary evidence that downregulation of the amygdala using rt-fMRI-NFB in PTSD is associated with dynamic changes in ICN, an effect similar to those observed using EEG modalities of neurofeedback.
Subject(s)
Amygdala/physiopathology , Magnetic Resonance Imaging , Neurofeedback , Stress Disorders, Post-Traumatic/physiopathology , Stress Disorders, Post-Traumatic/therapy , Amygdala/diagnostic imaging , Brain Mapping , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Neurofeedback/methods , Preliminary Data , Stress Disorders, Post-Traumatic/diagnostic imaging , Visual Perception/physiologyABSTRACT
Dissociative experiences have been associated with increased disease severity, chronicity, and, in some cases, reduced treatment response across trauma-related and other psychiatric disorders. A better understanding of the neurobiological mechanisms through which dissociative experiences occur may assist in identifying novel pharmacological and non-pharmacological treatment approaches. Here, we review emerging work on the dissociative subtype of posttraumatic stress disorder (PTSD), and other trauma-related disorders providing evidence for two related overarching neurobiological models of dissociation, the defense cascade model of dissociation and Mobb's threat detection model. In particular, we review neuroimaging studies highlighting alterations in functional connectivity of key brain regions associated with these models, including connectivity between the prefrontal cortex, the amygdala and its complexes, the insula, and the periaqueductal gray. Work implicating the kappa-opioid and endocannabinoid systems in trauma-related dissociative experiences is also reviewed. Finally, we hypothesize mechanisms by which pharmacological modulation of these neurochemical systems may serve as promising transdiagnostic treatment modalities for individuals experiencing clinically significant levels of dissociation. Specifically, whereas kappa-opioid receptor antagonists may serve as a pharmacological vehicle for the selective targeting of dissociative symptoms and associated emotion overmodulation in the dissociative subtype of posttraumatic stress disorder and transdiagnostically, modulation of the endocannabinoid system may reduce symptoms associated with emotional undermodulation of the fight or flight components of the defense cascade model.
Subject(s)
Analgesics, Opioid/adverse effects , Cannabinoids/adverse effects , Dissociative Disorders/physiopathology , Dissociative Disorders/psychology , Stress Disorders, Post-Traumatic/physiopathology , Stress Disorders, Post-Traumatic/psychology , Translational Research, Biomedical , Brain/physiopathology , Dissociative Disorders/chemically induced , Dissociative Disorders/therapy , Emotions/drug effects , Humans , Models, Neurological , Neurobiology , Stress Disorders, Post-Traumatic/chemically induced , Stress Disorders, Post-Traumatic/therapyABSTRACT
BACKGROUND: Mental disorders constitute a significant public health problem worldwide. Ensuring that those who need mental health services access them in an appropriate and timely manner is thus an important public health priority. We used data from 4 cross-sectional, nationally representative population health surveys that employed nearly identical methods to compare MHSU trends in the Canadian military versus comparable civilians. METHOD: The surveys were all conducted by Statistics Canada, approximately a decade apart (Military-2002, Military-2013, Civilian-2002, and Civilian-2012). The sample size for the pooled data across the surveys was 35,984. Comparisons across the 4 surveys were adjusted for differences in need in the 2 populations at the 2 time points. RESULTS: Our findings suggested that first, in the Canadian military, there was a clear and consistent pattern of improvement (i.e., increase) in MHSU over the past decade across a variety of provider types. The magnitudes of the changes were large, representing an absolute increase of 7.15% in those seeking any professional care, corresponding to an 84% relative increase. Second, in comparable Canadian civilians, MHSU remained either unchanged or increased only slightly. Third, the increases in MHSU over time were consistently greater in the military than in the comparable civilian sample. CONCLUSIONS: Our findings point to advantages with respect to MHSU of the military mental health system over the civilian system in Canada; these advantages have widened substantially over time. These findings speak strongly to the potential impact of analogous changes in other health systems, both military and civilian.
Subject(s)
Health Services Accessibility/statistics & numerical data , Mental Disorders/therapy , Mental Health Services/statistics & numerical data , Military Personnel/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Adolescent , Adult , Canada , Cross-Sectional Studies , Female , Health Care Surveys/statistics & numerical data , Humans , Male , Mental Health Services/economics , Middle Aged , Young AdultABSTRACT
This paper has been substantially revised by the Canadian Psychiatric Association's Research Committee and approved for republication by the CPA's Board of Directors on May 3, 2017. The original policy paper1 was developed by the Scientific and Research Affairs Standing Committee and approved by the Board of Directors on November 10, 2008.
Subject(s)
Guidelines as Topic/standards , Mass Media/standards , Psychiatry/standards , Societies, Medical/standards , Suicide , Canada , HumansABSTRACT
OBJECTIVES: To characterise a panel of neuroinjury-related blood biomarkers after sport-related concussion (SRC). We hypothesised significant differences in biomarker profiles between athletes with SRC and healthy controls at both subacute and medical clearance time points. METHODS: Thirty-eight interuniversity athletes were recruited over two athletic seasons (n = 19 SRC; n = 19 healthy matched-control). High-sensitivity immunoassay was used to evaluate 11 blood analytes at both the subacute phase after SRC and at medical clearance. RESULTS: Univariate analysis identified elevated circulating peroxiredoxin-6 (PRDX-6) in athletes with SRC compared to healthy controls at the subacute time point. Multivariate analyses yielded similar results in the subacute phase, but identified both PRDX-6 and T-tau as significant contributors to class separation between athletes with SRC and controls at medical clearance. CONCLUSIONS: Our results are consistent with the increasing recognition that physiological recovery after SRC extends beyond clinical recovery. Blood biomarkers appear to be useful in elucidating the biology of brain restitution after SRC. However, their implementation requires mindfulness of factors such as academic stress, exercise, and injury heterogeneity.
Subject(s)
Athletic Injuries/complications , Biomarkers/blood , Brain Concussion/etiology , Recovery of Function/physiology , Adolescent , Athletic Injuries/blood , Blood Proteins/metabolism , Brain Concussion/blood , Case-Control Studies , Cytokines/blood , Female , Humans , Male , Multivariate Analysis , Nerve Tissue Proteins/blood , Young AdultABSTRACT
Post-traumatic stress disorder (PTSD) is an anxiety disorder arising from exposure to a traumatic event. Although primarily defined in terms of behavioral symptoms, the global neurophysiological effects of traumatic stress are increasingly recognized as a critical facet of the human PTSD phenotype. Here we use magnetoencephalographic recordings to investigate two aspects of information processing: inter-regional communication (measured by functional connectivity) and the dynamic range of neural activity (measured in terms of local signal variability). We find that both measures differentiate soldiers diagnosed with PTSD from soldiers without PTSD, from healthy civilians, and from civilians with mild traumatic brain injury, which is commonly comorbid with PTSD. Specifically, soldiers with PTSD display inter-regional hypersynchrony at high frequencies (80-150 Hz), as well as a concomitant decrease in signal variability. The two patterns are spatially correlated and most pronounced in a left temporal subnetwork, including the hippocampus and amygdala. We hypothesize that the observed hypersynchrony may effectively constrain the expression of local dynamics, resulting in less variable activity and a reduced dynamic repertoire. Thus, the re-experiencing phenomena and affective sequelae in combat-related PTSD may result from functional networks becoming "stuck" in configurations reflecting memories, emotions, and thoughts originating from the traumatizing experience. SIGNIFICANCE STATEMENT: The present study investigates the effects of post-traumatic stress disorder (PTSD) in combat-exposed soldiers. We find that soldiers with PTSD exhibit hypersynchrony in a circuit of temporal lobe areas associated with learning and memory function. This rigid functional architecture is associated with a decrease in signal variability in the same areas, suggesting that the observed hypersynchrony may constrain the expression of local dynamics, resulting in a reduced dynamic range. Our findings suggest that the re-experiencing of traumatic events in PTSD may result from functional networks becoming locked in configurations that reflect memories, emotions, and thoughts associated with the traumatic experience.
Subject(s)
Brain Mapping , Brain/physiopathology , Nonlinear Dynamics , Stress Disorders, Post-Traumatic/pathology , Adult , Algorithms , Biological Clocks , Case-Control Studies , Entropy , Humans , Magnetoencephalography , Male , Military Personnel , Spectrum AnalysisABSTRACT
OBJECTIVE: Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast, PTSD patients with the dissociative subtype (PTSD + DS) often exhibit increased mPFC top-down modulation and decreased amygdala activation associated with emotional detachment and hypoarousal. Crucially, PTSD and PTSD + DS display distinct functional connectivity within the PFC, amygdala complexes, and the periaqueductal gray (PAG), a region related to defensive responses/emotional coping. However, differences in directed connectivity between these regions have not been established in PTSD, PTSD + DS, or controls. METHODS: To examine directed (effective) connectivity among these nodes, as well as group differences, we conducted resting-state stochastic dynamic causal modeling (sDCM) pairwise analyses of coupling between the ventromedial (vm)PFC, the bilateral basolateral and centromedial (CMA) amygdala complexes, and the PAG, in 155 participants (PTSD [n = 62]; PTSD + DS [n = 41]; age-matched healthy trauma-unexposed controls [n = 52]). RESULTS: PTSD was characterized by a pattern of predominant bottom-up connectivity from the amygdala to the vmPFC and from the PAG to the vmPFC and amygdala. Conversely, PTSD + DS exhibited predominant top-down connectivity between all node pairs (from the vmPFC to the amygdala and PAG, and from the amygdala to the PAG). Interestingly, the PTSD + DS group displayed the strongest intrinsic inhibitory connections within the vmPFC. CONCLUSIONS: These results suggest the contrasting symptom profiles of PTSD and its dissociative subtype (hyper- vs. hypo-emotionality, respectively) may be driven by complementary changes in directed connectivity corresponding to bottom-up defensive fear processing versus enhanced top-down regulation. Hum Brain Mapp 38:5551-5561, 2017. © 2017 Wiley Periodicals, Inc.
Subject(s)
Brain Mapping/methods , Brain/physiopathology , Dissociative Disorders/physiopathology , Magnetic Resonance Imaging/methods , Stress Disorders, Post-Traumatic/physiopathology , Adult , Adult Survivors of Child Adverse Events , Bayes Theorem , Brain/diagnostic imaging , Dissociative Disorders/diagnostic imaging , Fear/physiology , Female , Humans , Male , Multivariate Analysis , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Stress Disorders, Post-Traumatic/diagnostic imaging , Stress Disorders, Post-Traumatic/psychologyABSTRACT
Amygdala dysregulation has been shown to be central to the pathophysiology of posttraumatic stress disorder (PTSD) representing a critical treatment target. Here, amygdala downregulation was targeted using real-time fMRI neurofeedback (rt-fMRI-nf) in patients with PTSD, allowing us to examine further the regulation of emotional states during symptom provocation. Patients (n = 10) completed three sessions of rt-fMRI-nf with the instruction to downregulate activation in the amygdala, while viewing personalized trauma words. Amygdala downregulation was assessed by contrasting (a) regulate trials, with (b) viewing trauma words and not attempting to regulate. Training was followed by one transfer run not involving neurofeedback. Generalized psychophysiological interaction (gPPI) and dynamic causal modeling (DCM) analyses were also computed to explore task-based functional connectivity and causal structure, respectively. It was found that PTSD patients were able to successfully downregulate both right and left amygdala activation, showing sustained effects within the transfer run. Increased activation in the dorsolateral and ventrolateral prefrontal cortex (PFC), regions related to emotion regulation, was observed during regulate as compared with view conditions. Importantly, activation in the PFC, rostral anterior cingulate cortex, and the insula, were negatively correlated to PTSD dissociative symptoms in the transfer run. Increased functional connectivity between the amygdala- and both the dorsolateral and dorsomedial PFC was found during regulate, as compared with view conditions during neurofeedback training. Finally, our DCM analysis exploring directional structure suggested that amygdala downregulation involves both top-down and bottom-up information flow with regard to observed PFC-amygdala connectivity. This is the first demonstration of successful downregulation of the amygdala using rt-fMRI-nf in PTSD, which was critically sustained in a subsequent transfer run without neurofeedback, and corresponded to increased connectivity with prefrontal regions involved in emotion regulation during the intervention. Hum Brain Mapp 38:541-560, 2017. © 2016 Wiley Periodicals, Inc.
Subject(s)
Amygdala/physiopathology , Brain/diagnostic imaging , Emotions/physiology , Magnetic Resonance Imaging , Stress Disorders, Post-Traumatic/pathology , Stress Disorders, Post-Traumatic/physiopathology , Adult , Amygdala/diagnostic imaging , Analysis of Variance , Feedback, Sensory/physiology , Female , Humans , Image Processing, Computer-Assisted , Male , Middle Aged , Models, Neurological , Oxygen/blood , Stress Disorders, Post-Traumatic/diagnostic imagingABSTRACT
Accurate means to detect mild traumatic brain injury (mTBI) using objective and quantitative measures remain elusive. Conventional imaging typically detects no abnormalities despite post-concussive symptoms. In the present study, we recorded resting state magnetoencephalograms (MEG) from adults with mTBI and controls. Atlas-guided reconstruction of resting state activity was performed for 90 cortical and subcortical regions, and calculation of inter-regional oscillatory phase synchrony at various frequencies was performed. We demonstrate that mTBI is associated with reduced network connectivity in the delta and gamma frequency range (>30 Hz), together with increased connectivity in the slower alpha band (8-12 Hz). A similar temporal pattern was associated with correlations between network connectivity and the length of time between the injury and the MEG scan. Using such resting state MEG network synchrony we were able to detect mTBI with 88% accuracy. Classification confidence was also correlated with clinical symptom severity scores. These results provide the first evidence that imaging of MEG network connectivity, in combination with machine learning, has the potential to accurately detect and determine the severity of mTBI.
Subject(s)
Brain Injuries, Traumatic/diagnostic imaging , Brain Mapping/methods , Brain/diagnostic imaging , Magnetoencephalography/methods , Signal Processing, Computer-Assisted , Adult , Brain/physiopathology , Brain Injuries, Traumatic/physiopathology , Cluster Analysis , Humans , Male , Young AdultABSTRACT
OBJECTIVES: Failure to perceive need for care (PNC) is the leading barrier to accessing mental health care. After accessing care, many individuals perceive that their needs were unmet or only partially met, an additional problem related to perceived sufficiency of care (PSC). The Canadian Armed Forces (CAF) invested heavily in workplace mental health in the past decade to improve PNC/PSC; yet, the impact of these investments remains unknown. To assess the impact of these investments, this study 1) captures changes in PNC/PSC over the past decade in the CAF and 2) compares current PNC/PSC between the CAF and civilians. METHODS: Data were drawn from the 2013 and 2002 CAF surveys and the 2012 civilian mental health survey (total N = â¼40 000), conducted by Statistics Canada using similar methodology. Exclusions were applied to the civilian sample to make them comparable to the military sample. Prevalence rates for No need, Need met, Need partially met, and Need unmet categories across service types (Information, Medication, Counselling and therapy, Any services) were calculated and compared between 1) the 2 CAF surveys and 2) the 2013 CAF and 2012 civilian surveys after sample matching. RESULTS: Reports of Any need and Need met were higher in the CAF in 2013 than in 2002 by approximately 6% to 8% and 2% to 8%, respectively, and higher in the CAF than in civilians by 3% to 10% and 2% to 8%, respectively. CONCLUSIONS: These results suggest that investments in workplace mental health, such as those implemented in the CAF, can lead to improvements in recognizing the need for care (PNC) and subsequently getting those needs met (PSC).
Subject(s)
Health Services Needs and Demand/statistics & numerical data , Mental Health Services/statistics & numerical data , Military Personnel/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Adult , Canada , Cross-Sectional Studies , Female , Health Care Surveys/statistics & numerical data , Humans , Male , Patient Satisfaction/statistics & numerical dataABSTRACT
OBJECTIVE: The 2013 Canadian Forces Mental Health Survey (CFMHS) collected detailed information on mental health problems, their impacts, occupational and nonoccupational determinants of mental health, and the use of mental health services from a random sample of 8200 serving personnel. The objective of this article is to provide a firm scientific foundation for understanding and interpreting the CFMHS findings. METHODS: This narrative review first provides a snapshot of the Canadian Armed Forces (CAF), focusing on 2 key determinants of mental health: the deployment of more than 40,000 personnel in support of the mission in Afghanistan and the extensive renewal of the CAF mental health system. The findings of recent population-based CAF mental health research are reviewed, with a focus on findings from the very similar mental health survey done in 2002. Finally, key aspects of the methods of the 2013 CFMHS are presented. RESULTS: The findings of 20 peer-reviewed publications using the 2002 mental health survey data are reviewed, along with those of 25 publications from other major CAF mental health research projects executed over the past decade. CONCLUSIONS: More than a decade of population-based mental health research in the CAF has provided a detailed picture of its mental health and use of mental health services. This knowledge base and the homology of the 2013 survey with the 2002 CAF survey and general population surveys in 2002 and 2012 will provide an unusual opportunity to use the CFMHS to situate mental health in the CAF in a historical and societal perspective.