Nonconventional interventions for chronic post-traumatic stress disorder: Ketamine, repetitive trans-cranial magnetic stimulation (rTMS), and alternative approaches

Effects of intermittent theta-burst transcranial magnetic stimulation on post-traumatic stress disorder symptoms: A randomized controlled trial

Post-traumatic stress disorder (PTSD) is a prevalent and debilitating illness, which can be alleviated by transcranial magnetic stimulation (TMS). Intermittent theta burst stimulation (iTBS), a newer form of repetitive transcranial magnetic stimulation (rTMS), offers the advantage of shorter treatment sessions compared to the standard 10 Hz rTMS treatment. In order to compare the two forms of TMS, we enrolled 75 participants aged between 18 and 55 years who presented with (PCL-C) scale score of at least 50. Participants were randomly assigned to groups in a ratio of 1:1:1, receiving either 10 Hz rTMS, iTBS, or sham-controlled iTBS. Participants in the two treatment groups underwent 15 therapies which consisted of 1800 pulses and targeted the right dorsolateral prefrontal cortex (DLPFC). The main outcomes included changes in scores on the PCL-C and the Post-Traumatic Growth Inventory (PTGI). After intervention, the PCL-C and PTGI scores in iTBS and rTMS groups were significantly different from those in sham-controlled iTBS group. No significant differences in PCL-C and PTGI were found between the two active treatment groups. ITBS, with a shorter treatment duration, can effectively improve the symptoms of PTSD, with no significant difference in effect from that of rTMS. Future studies need to further elucidate the mechanisms, optimize the parameters and investigate the therapeutic potential and efficacy of iTBS in PTSD.

The Use of Repetitive Transcranial Magnetic Stimulations for the Treatment of Post-Traumatic Stress Disorder: A Scoping Review

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive procedure in which brain neural activity is stimulated by the direct application of a magnetic field to the scalp. Despite its wide and continuous usage for the management of psychiatric disorders, the use of rTMS for post-traumatic stress disorder (PTSD) is not well established and evaluated by researchers. This scoping review seeks to explore the relevant literature available regarding the use of rTMS as a mode of treatment for PTSD, to map evidence in support of the use of rTMS for PTSD, and recommendations on future clinical and research work. Five databases were searched (MEDLINE, CINAHL, Psych INFO, SCOPUS, and EMBASE) to identify empirical studies and randomized controlled trials aimed at the treatment of PTSD with rTMS. A total of 10 studies were eligible for this review. The search results are up to date as of the date of the electronic data search of 20 December 2020. The frequencies applied in the studies ranged from low (1 Hz) to high (10 Hz) at different thresholds. Nine reported significant positive outcomes and PTSD symptoms improvement. rTMS was reported as well tolerated with no significant side effects. The application of rTMS for PTSD looks promising despite the diversity in terms of its outcomes and its clinical significance. Studies with well-defined stimulation parameters need to be conducted in the future.

Transcranial magnetic stimulation as a treatment for posttraumatic stress disorder: A meta-analysis

BACKGROUND

Posttraumatic stress disorder (PTSD) is a pervasive mental health condition with limited treatment success. Transcranial magnetic stimulation (TMS) has shown positive outcomes for people with PTSD, using different treatment protocols. This meta-analysis sought to examine which variables in TMS treatment are associated with treatment benefits.

METHODS

A literature search of major online research databases from inception to September 15, 2020 was conducted to identify primary research studies using TMS to treat PTSD. Treatment effect data and TMS treatment variables were coded and analysed using a random effects model. Meta-regression and analyses of moderating variables were conducted to ascertain which variables were associated with significant treatment effects.

RESULTS

An overall effect size of d = 1.17, 95% CI [0.89 - 1.45] for TMS as a treatment for PTSD was found. Analysis of moderators showed that there was a significantly larger treatment effect for high frequency TMS (d = 1.44) compared with low frequency (d = 0.72), p = .006; there was no significant difference between TMS targeting the left dorsolateral prefrontal cortex (DLPFC) and the right DLPFC; and larger treatment doses were not associated with stronger treatment effects.

LIMITATIONS

Not all published studies were available in English or reported the necessary data to be included in this meta-analysis.

CONCLUSIONS

TMS shows potential as a treatment for PTSD, although further research is required to understand the neurological mechanisms of TMS on specific PTSD symptoms so that more effective treatment can be designed for individuals.

Ketamine for post-traumatic stress disorders and it's possible therapeutic mechanism

Posttraumatic stress disorder (PTSD) is a devastating medical illness, for which currently available pharmacotherapies have poor efficacy. Accumulating evidence from clinical and preclinical animal investigations supports that ketamine exhibits a rapid and persistent effect against PTSD, though the underlying molecular mechanism remains to be clarified. In this literature review, we recapitulate the achievements from early ketamine studies to the most up-to-date discoveries, with an effort to discuss an inclusive therapeutic role of ketamine for PTSD treatment and its possible therapeutic mechanism. Ketamine seems to have an inimitable mechanism of action entailing glutamate modulation via actions at the N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors, as well as downstream activation of brain-derived neurotrophic factor (BDNF) and mechanistic target of rapamycin (mTOR) signaling pathways to potentiate synaptic plasticity.

Combining Ketamine, Brain Stimulation (rTMS) and Mindfulness Therapy (TIMBER) for Opioid Addiction

Opioid addiction in the United States currently presents a national crisis despite availability of different treatments. Prior findings suggest that both repetitive transcranial magnetic stimulation (rTMS) and subanesthetic dose of ketamine are efficacious in patients with opioid use disorders (OUD) when administered in isolation. However, their therapeutic value may be undermined by varying clinical responses that tend to dissipate with treatment cessation. There has been no study to date that has used a combination of both for OUD, and there are still many unanswered questions with respect to both. TIMBER (Trauma Interventions using Mindfulness Based Extinction and Reconsolidation of memories) therapy attempts to alter the expression of emotionally charged memories such as traumatic memories, and has been successfully tried in chronic post-traumatic stress disorder (PTSD) and in combination with memory-altering pharmacotherapy like ketamine infusion. By a combination of extinction and reconsolidation of memory approaches, TIMBER works to not over-flood and/or retraumatize as is seen in other treatment approaches. TIMBER involves a balanced combination of both the memory extinction and memory reconsolidation approaches (rather than extinction-only approaches) which explains its superior efficacy in PTSD and benefit in substance use disorders.

Characteristic patterns of EEG oscillations in sheep (Ovis aries) induced by ketamine may explain the psychotropic effects seen in humans

Ketamine is a valuable anaesthetic and analgesic that in recent years has gained notoriety as a recreational drug. Recently, ketamine has also been proposed as a novel treatment for depression and post-traumatic stress disorder. Beyond its anaesthetic actions, however, the effects of ketamine on brain activity have rarely been probed. Here we examined the cortical electroencephalography (EEG) response to ketamine of 12 sheep. Following ketamine administration, EEG changes were immediate and widespread, affecting the full extent of the EEG frequency spectrum measured (0–125 Hz). After recovery from sedation during which low frequency activity dominated, the EEG was characterised by short periods (2–3 s) of alternating low (<14 Hz) and high (>35 Hz) frequency oscillation. This alternating EEG rhythm phase is likely to underlie the dissociative actions of ketamine, since it is during this phase that ketamine users report hallucinations. At the highest intravenous dose used (24 mg/kg), in 5/6 sheep we observed a novel effect of ketamine, namely the complete cessation of cortical EEG activity. This persisted for up to several minutes, after which cortical activity resumed. This phenomenon is likely to explain the ‘k-hole’, a state of oblivion likened to a near death experience that is keenly sought by ketamine abusers.

Ketamine Alleviates Fear Generalization Through GluN2B-BDNF Signaling in Mice

Fear memories are critical for survival. Nevertheless, over-generalization of these memories, depicted by a failure to distinguish threats from safe stimuli, is typical in stress-related disorders. Previous studies have supported a protective role of ketamine against stress-induced depressive behavior. However, the effect of ketamine on fear generalization remains unclear. In this study, we investigated the effects of ketamine on fear generalization in a fear-generalized mouse model. The mice were given a single sub-anesthetic dose of ketamine (30 mg/kg, i.p.) 1 h before, 1 week before, immediately after, or 22 h after fear conditioning. The behavioral measure of fear (indicated by freezing level) and synaptic protein expression in the basolateral amygdala (BLA) and inferior-limbic pre-frontal cortex (IL-PFC) of mice were examined. We found that only ketamine administered 22 h after fear conditioning significantly decreased the fear generalization, and the effect was dose-dependent and lasted for at least 2 weeks. The fear-generalized mice showed a lower level of brain-derived neurotrophic factor (BDNF) and a higher level of GluN2B protein in the BLA and IL-PFC, and this was reversed by a single administration of ketamine. Moreover, the GluN2B antagonist ifenprodil decreased the fear generalization when infused into the IL-PFC, but had no effect when infused into the BLA. Infusion of ANA-12 (an antagonist of the BDNF receptor TrkB) into the BLA or IL-PFC blocked the effect of ketamine on fear generalization. These findings support the conclusion that a single dose of ketamine administered 22 h after fear conditioning alleviates the fear memory generalization in mice and the GluN2B-related BDNF signaling pathway plays an important role in the alleviation of fear generalization.

Emerging areas of transcranial magnetic stimulation use in psychiatry

Transcranial magnetic stimulation (TMS) is most widely known clinically as a treatment for medication-refractory major depressive disorder, but it holds promise in a number of other areas. In addition to emerging neurologic areas of investigation such as in mild cognitive impairment, dementia, Parkinson's disease and stroke rehab, novel approaches to psychiatric conditions are also being explored. This review provides a critical condensation of the available data assessing the efficacy of TMS in the treatment of other psychiatric conditions, namely bipolar disorder, substance use, post-traumatic stress disorder and other anxiety disorders. Each section details the field's current accumulation of evidence of the respective condition's pathophysiology in the context of a discussion of the relevant therapeutic target(s) of TMS. Each section then reviews both positive and negative studies evaluating TMS in clinical practice. Given the relative tolerability and proven efficacy of TMS in treatment-resistant depression (TRD), further study to determine its therapeutic effect in other psychiatric entities is warranted.

Prophylactic Ketamine Attenuates Learned Fear

Ketamine has been reported to be an efficacious antidepressant for major depressive disorder and posttraumatic stress disorder. Most recently, ketamine has also been shown to be prophylactic against stress-induced depressive-like behavior in mice. It remains unknown, however, when ketamine should be administered relative to a stressor in order to maximize its antidepressant and/or prophylactic effects. Moreover, it is unknown whether ketamine can be prophylactic against subsequent stressors. We systematically administered ketamine at different time points relative to a fear experience, in order to determine when ketamine is most effective at reducing fear expression or preventing fear reactivation. Using a contextual fear conditioning (CFC) paradigm, mice were administered a single dose of saline or ketamine (30 mg/kg) at varying time points before or after CFC. Mice administered prophylactic ketamine 1 week, but not 1 month or 1 h before CFC, exhibited reduced freezing behavior when compared with mice administered saline. In contrast, ketamine administration following CFC or during extinction did not alter subsequent fear expression. However, ketamine administered before reinstatement increased the number of rearing bouts in an open field, possibly suggesting an increase in attentiveness. These data indicate that ketamine can buffer a fear response when given a week before as prophylactic, but not when given immediately before or after a stress-inducing episode. Thus, ketamine may be most useful in the clinic if administered in a prophylactic manner 1 week before a stressor, in order to protect against heightened fear responses to aversive stimuli.

PTSD in Court II: Risk factors, endophenotypes, and biological underpinnings in PTSD

The second article in the series of three for the journal on "PTSD in Court" especially concerns the biological bases that have been found to be associated with PTSD (posttraumatic stress disorder). The cohering concepts in this section relate to risk factors; candidate genes; polygenetics; "gene×environment" interactions; epigenetics; endophenotypes; biomarkers; and connective networks both structurally and functionally (in terms of intrinsic connectivity networks, ICNs, including the DMN, SN, and CEN; that is, default mode, salience, and central executive networks, respectively). Risk factors related to PTSD include pre-event, event- and post-event ones. Some of the genes related to PTSD include: FKBP5, 5-HTTLPR, and COMT (which are, respectively, FK506-binding protein 5 gene, serotonin-transporter linked polymorphic region, catechol-O-methyl-transferase). These genetic findings give an estimate of 30% for the genetic influence on PTSD. The typical brain regions involved in PTSD include the amygdala, hippocampus, and prefrontal cortex, along with the insula. Causal models of behavior are multifactorial and biopsychosocial, and these types of models apply to PTSD, as well. The paper presents a multilevel systems model of psychopathology, including PTSD, which involves three levels - a top-down psychological construct one, a bottom-up symptom connection one, and a middle one involving symptom appraisal. Legally, causality refers to the event at issue needing to meet the bar of being materially contributory to the outcome. Finally, this section of the article reviews empirically-supported therapies for PTSD and the dangers of not receiving treatment for it.

Ketamine, Transcranial Magnetic Stimulation, and Depression Specific Yoga and Mindfulness Based Cognitive Therapy in Management of Treatment Resistant Depression: Review and Some Data on Efficacy

Depression affects about 121 million people worldwide and prevalence of major depressive disorder (MDD) in US adults is 6.4%. Treatment resistant depression (TRD) accounts for approximately 12-20% of all depression patients and costs $29-$48 billion annually. Ketamine and repetitive transcranial magnetic stimulation (rTMS) have useful roles in TRD, but their utility in long term is unknown. As per the latest literature, the interventions using Yoga and meditation including the mindfulness based cognitive therapy (MBCT) have been useful in treatment of depression and relapse prevention. We present a review of rTMS, ketamine, and MBCT and also report efficacy of a depression specific, innovative, and translational model of Yoga and mindfulness based cognitive therapy (DepS Y-MBCT), developed by the first author. DepS Y-MBCT as an adjunctive treatment successfully ameliorated TRD symptoms in 27/32 patients in an open label pilot trial in TRD patients. Considering the limitations of existing treatment options, including those of ketamine and rTMS when used as the sole modality of treatment, we suggest a "tiered approach for TRD" by combining ketamine and rTMS (alone or along with antidepressants) for rapid remission of acute depression symptoms and to use DepS Y-MBCT for maintaining remission and preventing relapse.