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Determining how patients distinguish auditory verbal hallucinations (AVHs) from their everyday thoughts may shed light on neurocognitive processes leading to these symptoms.
Method
Fifty patients reporting active AVHs (‘voices’) with a diagnosis of schizophrenia or schizo-affective disorder were surveyed using a structured questionnaire. Data were collected to determine: (a) the degree to which patients distinguished voices from their own thoughts; (b) the degree to which their thoughts had verbal form; and (c) the experiential basis for identifying experiences as voices versus their own verbal thoughts. Six characteristics of acoustic/verbal images were considered: (1) non-self speaking voice, (2) loudness, (3) clarity, (4) verbal content, (5) repetition of verbal content, and (6) sense of control.
Results
Four subjects were eliminated from the analysis because they reported absent verbal thought or a total inability to differentiate their own verbal thoughts from voices. For the remaining 46 patients, verbal content and sense of control were rated as most salient in distinguishing voices from everyday thoughts. With regard to sensory/perceptual features, identification of speaking voice as non-self was more important in differentiating voices from thought than either loudness or clarity of sound images.
Conclusions
Most patients with schizophrenia and persistent AVHs clearly distinguish these experiences from their everyday thoughts. An adequate mechanistic model of AVHs should account for distinctive content, recognizable non-self speaking voices, and diminished sense of control relative to ordinary thought. Loudness and clarity of sound images appear to be of secondary importance in demarcating these hallucination experiences.
Suicide is the most common cause of death among youth in China.
Method
A case-control psychological autopsy study in 23 geographically representative disease surveillance points around China collected information from family members and close associates of 114 persons aged 15–24 years who died by suicide (cases) and 91 who died of other injuries (controls).
Results
Among the 114 suicides 61% were female, 88% lived in rural villages, 70% died by ingesting pesticides (most commonly stored in the home), 24% previously attempted suicide, and 45% met criteria of a mental illness at the time of death. Multivariate logistic regression identified several independent risk factors: severe life events within 2 days before death (OR 31.8, 95% CI 2.6–390.6), presence of any depressive symptoms within 2 weeks of death (OR 21.1, 95% CI 4.6–97.2), low quality of life in the month before death (OR 9.7, 95% CI 2.8–34.1), and acute stress at time of death (moderate: OR 3.1, 95% CI 0.8–11.9; high: OR 9.1, 95% CI 1.2–66.8). A significant interaction between mental illness at time of death and gender indicated that diagnosis was an important predictor of suicide in males (OR 14.0, 95% CI 2.6–76.5) but not in females (OR 0.3, 95% CI 0.0–3.6). Prior suicide attempt was related to suicide in the univariate analysis (OR 57.5) but could not be included in the multivariate model because no controls had made prior attempts.
Conclusions
Suicide prevention efforts for youth in China must focus on restricting access to pesticides, early recognition and management of depressive symptoms and mental illnesses, improving resiliency, and enhancing quality of life.
Ocular-motor inhibition errors and saccadic hypometria occur at elevated rates in biological relatives of schizophrenic patients. The memory-guided saccade (MS) paradigm requires a subject to inhibit reflexive saccades (RSs) and to programme a delayed saccade towards a remembered target.
Method
MS, RS, and central fixation (CF) tasks were administered to 16 patients who met the criteria for DSM-IV schizophrenia, 19 of their psychiatrically healthy siblings, and 18 controls.
Results
Patients and siblings showed elevated MS error rates reflecting a failure to inhibit RSs to a visible target, as required by the task. In contrast to controls, prior errors did not improve MS accuracy in patients and siblings.
Conclusions
The specific characteristics of the elevated MS error rate help to clarify the nature of the disinhibition impairment found in schizophrenics and their healthy siblings. Failure to inhibit premature saccades and to improve the accuracy of subsequent volitional saccades implicates a deficit in spatial working-memory integration, mental representation and/or motor learning processes in schizophrenia.
Clinical guidelines advise against prescribing more than one antipsychotic with limited exceptions. Despite this, surveys continue to report high antipsychotic polypharmacy rates. The aim of the study was to investigate the effectiveness of a multi-faceted intervention in reducing prescribing of antipsychotic polypharmacy on general adult psychiatry wards, compared with guidelines alone.
Method
A pragmatic cluster randomized controlled trial recruited 19 adult psychiatric units (clusters) from the South West of England. Participants were all ward doctors and nurses. The multi-faceted intervention comprised: an educational/CBT workbook; an educational visit to consultants; and a reminder system on medication charts.
Results
The odds of being prescribed antipsychotic polypharmacy in those patients prescribed antipsychotic medication was significantly lower in the intervention than control group when adjusted for confounders (OR 0.43, 95% CI 0.21–0.90, p=0.028). There was considerable between-unit variation in polypharmacy rates and in the change in rates between baseline and follow-up (5 months after baseline).
Conclusion
The intervention reduced levels of polypharmacy prescribing compared to guidelines alone although the effect size was relatively modest. Further work is needed to elicit the factors that were active in changing prescribing behaviour.
Collaborative care is an effective intervention for depression which includes both organizational and patient-level intervention components. The effect in the UK is unknown, as is whether cluster- or patient-randomization would be the most appropriate design for a Phase III clinical trial.
Method
We undertook a Phase II patient-level randomized controlled trial in primary care, nested within a cluster-randomized trial. Depressed participants were randomized to ‘collaborative care’ – case manager-coordinated medication support and brief psychological treatment, enhanced specialist and GP communication – or a usual care control. The primary outcome was symptoms of depression (PHQ-9).
Results
We recruited 114 participants, 41 to the intervention group, 38 to the patient randomized control group and 35 to the cluster-randomized control group. For the intervention compared to the cluster control the PHQ-9 effect size was 0.63 (95% CI 0.18–1.07). There was evidence of substantial contamination between intervention and patient-randomized control participants with less difference between the intervention group and patient-randomized control group (−2.99, 95% CI −7.56 to 1.58, p=0.186) than between the intervention and cluster-randomized control group (−4.64, 95% CI −7.93 to −1.35, p=0.008). The intra-class correlation coefficient for our primary outcome was 0.06 (95% CI 0.00–0.32).
Conclusions
Collaborative care is a potentially powerful organizational intervention for improving depression treatment in UK primary care, the effect of which is probably partly mediated through the organizational aspects of the intervention. A large Phase III cluster-randomized trial is required to provide the most methodologically accurate test of these initial encouraging findings.
The attention-grabbing properties of drugs to drug-using individuals have been well documented and recent research has begun to suggest that such attentional bias may be related to the severity of drug dependency. Dependence on ketamine has been reported anecdotally but no systematic study has investigated this phenomenon. We aimed to explore attentional biases to incentive stimuli in different populations of ketamine users.
Method
Using a dot-probe paradigm, attentional bias to both drug-related and money-related stimuli was investigated in 150 participants: 30 frequent ketamine users, 30 infrequent ketamine users, 30 ex-ketamine users, 30 poly-drug users and 30 non-drug-using controls. Two stimulus presentation times were used (200 and 2000 ms) to investigate whether attentional bias was as a result of an automatic or a more conscious attentional shift. Participants also rated the degree to which stimuli used in the dot-probe paradigm were pleasurable.
Results
Frequent ketamine users demonstrated an attentional bias to both types of incentive stimuli only at the short stimulus presentation interval and this was significantly correlated with degree of ketamine use. No attentional biases were observed in any of the other groups. All groups rated money stimuli as more pleasurable than neutral stimuli.
Conclusions
These data support incentive models of drug use and demonstrate the ability of the attentional bias paradigm to discriminate recreational drug users from those with more dependent patterns of use. Ketamine is a potentially dependence-forming drug.
Results of studies on antisaccade (AS) deficit in relatives of patients with schizophrenia are inconclusive. We hypothesized that AS performance in siblings of patients with schizophrenia is worse than in healthy controls and better than in patients with schizophrenia.
Method
We included 55 first-episode patients with schizophrenia, 28 healthy siblings and 36 healthy controls to evaluate AS performance. Eye movements were measured electromagnetically by the double magnetic induction (DMI) method.
Results
Patients with schizophrenia had a significantly higher error rate than siblings (d=0.86, p<0.0001) and controls (d=1.35, p<0.0001). Siblings had a higher mean error rate than healthy controls but this did not reach significance (d=0.56, p=0.29). The intra-class correlation (ICC) was 0.33 for the error rate. Mean AS gain was higher in siblings than in patients (d=0.75, p=0.004) and controls (d=0.6, p=0.05). The ICC was 0.08.
Conclusion
AS parameters in strictly screened healthy young siblings of young first-episode patients with schizophrenia are comparable to results found in studies investigating older relatives. However, the statistical results (i.e. the ICCs) suggest that there is little evidence of shared environmental or genetic factors on error rate variation.
Prior studies in the USA have reported higher rates of mental disorders amongpersons with arthritis but no cross-national studies have been conducted. Inthis study the prevalence of specific mental disorders among persons witharthritis was estimated and their association with arthritis across diversecountries assessed.
Method
The study was a series of cross-sectional population sample surveys. Eighteenpopulation surveys of household-residing adults were carried out in 17countries in different regions of the world. Most were carried out between2001 and 2002, but others were completed as late as 2007. Mental disorderswere assessed with the World Health Organization (WHO)World Mental Health–Composite International Diagnostic Interview(WMH-CIDI). Arthritis was ascertained by self-report.The association of anxiety disorders, mood disorders and alcohol usedisorders with arthritis was assessed, controlling for age and sex.Prevalence rates for specific mental disorders among persons with andwithout arthritis were calculated and odds ratios(ORs) with 95% confidence intervals wereused to estimate the association.
Results
After adjusting for age and sex, specific mood and anxiety disorders occurredamong persons with arthritis at higher rates than among persons withoutarthritis. Alcohol abuse/dependence showed a weaker and lessconsistent association with arthritis. The pooled estimates of the age- andsex-adjusted ORs were about 1.9 for mood disorders and for anxiety disordersand about 1.5 for alcohol abuse/dependence among persons withversus without arthritis. The patternof association between specific mood and anxiety disorders and arthritis wassimilar across countries.
Conclusions
Mood and anxiety disorders occur with greater frequency among persons witharthritis than those without arthritis across diverse countries. Thestrength of association of specific mood and anxiety disorders witharthritis was generally consistent across disorders and acrosscountries.
Dissociative reactions in post-traumatic stress disorder (PTSD) have been regarded as strategic responses that limit arousal. Neuroimaging studies suggest distinct prefrontal responses in individuals displaying dissociative and hyperarousal responses to threat in PTSD. Increased prefrontal activity may reflect enhanced regulation of limbic arousal networks in dissociation. If dissociation is a higher-order regulatory response to threat, there may be differential responses to conscious and automatic processing of threat stimuli. This study addresses this question by examining the impact of dissociation on fear processing at different levels of awareness.
Method
Functional magnetic resonance imaging (fMRI) with a 1.5-T scanner was used to examine activation to fearful (versus neutral) facial expressions during consciously attended and non-conscious (using backward masking) conditions in 23 individuals with PTSD. Activation in 11 individuals displaying non-dissociative reactions was compared to activation in 12 displaying dissociative reactions to consciously and non-consciously perceived fear stimuli.
Results
Dissociative PTSD was associated with enhanced activation in the ventral prefrontal cortex for conscious fear, and in the bilateral amygdala, insula and left thalamus for non-conscious fear compared to non-dissociative PTSD. Comparatively reduced activation in the dissociative group was apparent in dorsomedial prefrontal regions for conscious fear faces.
Conclusions
These findings confirm our hypotheses of enhanced prefrontal activity to conscious fear and enhanced activity in limbic networks to non-conscious fear in dissociative PTSD. This supports the theory that dissociation is a regulatory strategy invoked to cope with extreme arousal in PTSD, but this strategy appears to function only during conscious processing of threat.
A better understanding of the long-term scope and impact of the co-morbidity with oppositional defiant disorder (ODD) and conduct disorder (CD) in attention deficit hyperactivity disorder (ADHD) youth has important clinical and public health implications.
Method
Subjects were assessed blindly at baseline (mean age=10.7 years), 1-year (mean age=11.9 years), 4-year (mean age=14.7 years) and 10-year follow-up (mean age=21.7 years). The subjects' lifetime diagnostic status of ADHD, ODD and CD by the 4-year follow-up were used to define four groups (Controls, ADHD, ADHD plus ODD, and ADHD plus ODD and CD). Diagnostic outcomes at the 10-year follow-up were considered positive if full criteria were met any time after the 4-year assessment (interval diagnosis). Outcomes were examined using a Kaplan–Meier survival function (persistence of ODD), logistic regression (for binary outcomes) and negative binomial regression (for count outcomes) controlling for age.
Results
ODD persisted in a substantial minority of subjects at the 10-year follow-up. Independent of co-morbid CD, ODD was associated with major depression in the interval between the 4-year and the 10-year follow-up. Although ODD significantly increased the risk for CD and antisocial personality disorder, CD conferred a much larger risk for these outcomes. Furthermore, only CD was associated with significantly increased risk for psychoactive substance use disorders, smoking, and bipolar disorder.
Conclusions
These longitudinal findings support and extend previously reported findings from this sample at the 4-year follow-up indicating that ODD and CD follow a divergent course. They also support previous findings that ODD heralds a compromised outcome for ADHD youth grown up independently of the co-morbidity with CD.
It is unclear whether the association between impulsive-aggressive behaviours and suicide exists across different ages.
Method
Via psychological autopsy, we examined a total of 645 subjects aged 11–87 years who died by suicide. Proxy-based interviews were conducted using the SCID-I & SCID-II or K-SADS interviews and a series of behavioural and personality-trait assessments. Secondarily, 246 living controls were similarly assessed.
Results
Higher levels of impulsivity, lifetime history of aggression, and novelty seeking were associated with younger age of death by suicide, while increasing levels of harm avoidance were associated with increasing age of suicide. This effect was observed after accounting for age-related psychopathology (current and lifetime depressive disorders, lifetime anxiety disorders, current and lifetime substance abuse disorders, psychotic disorders and cluster B personality disorders). Age effects were not due to the characteristics of informants, and such effects were not observed among living controls. When directly controlling for major psychopathology, the interaction between age, levels of impulsivity, aggression and novelty seeking predicted suicide status while controlling for the independent contributions of age and these traits.
Conclusions
Higher levels of impulsive-aggressive traits play a greater role in suicide occurring among younger individuals, with decreasing importance with increasing age.
The association between poor mental health and poverty is well known but its mechanism is not fully understood. This study tests the hypothesis that the association between low income and mental disorder is mediated by debt and its attendant financial hardship.
Method
The study is a cross-sectional nationally representative survey of private households in England, Scotland and Wales, which assessed 8580 participants aged 16–74 years living in general households. Psychosis, neurosis, alcohol abuse and drug abuse were identified by the Clinical Interview Schedule – Revised, the Schedule for Assessment in Neuropsychiatry (SCAN), the Alcohol Use Disorder Identification Test (AUDIT) and other measures. Detailed questions were asked about income, debt and financial hardship.
Results
Those with low income were more likely to have mental disorder [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.68–2.59] but this relationship was attenuated after adjustment for debt (OR 1.58, 95% CI 1.25–1.97) and vanished when other sociodemographic variables were also controlled (OR 1.07, 95% CI 0.77–1.48). Of those with mental disorder, 23% were in debt (compared with 8% of those without disorder), and 10% had had a utility disconnected (compared with 3%). The more debts people had, the more likely they were to have some form of mental disorder, even after adjustment for income and other sociodemographic variables. People with six or more separate debts had a six-fold increase in mental disorder after adjustment for income (OR 6.0, 95% CI 3.5–10.3).
Conclusions
Both low income and debt are associated with mental illness, but the effect of income appears to be mediated largely by debt.
Patients treated in primary care settings report better mental outcomes when they agree with practitioners about the nature of their core presenting problems. However, no study has examined the impact of staff–patient agreement on treatment outcomes in specialist mental health services. We investigated whether a better staff–patient agreement on needs for care predicts more favourable outcome in patients receiving community-based psychiatric care.
Method
A 3-month prevalence cohort of 188 patients with the full spectrum of psychiatric conditions was assessed at baseline and at 4 years using the Camberwell Assessment of Need (CAN), both staff (CAN-S) and patient versions (CAN-P), and a set of standardized outcome measures. Baseline staff–patient agreement on needs was included among predictors of outcome. Both clinician-rated (psychopathology, social disability, global functioning) and patient-rated (subjective quality of life and satisfaction with services) outcomes were considered.
Results
Controlling for the effect of sociodemographics, service utilization and changes in clinical status, better staff–patient agreement makes a significant additional contribution in predicting treatment outcomes not only on patient-rated but also on clinician-rated measures.
Conclusions
Mental health care should be provided on the basis of a negotiation process involving both professionals and service users to ensure effective interventions; every effort should be made by services to implement strategies aiming to increase consensus between staff and patients.
The aim was to reduce non-attendance for first-time consultations at psychiatric out-patient clinics.
Method
The study was a pragmatic randomized controlled trial; the setting was seven inner-city UK out-patient clinics in Leeds. The participants were 764 subjects of working age with an appointment to attend a psychiatric out-patient clinic for the first time. The intervention was an ‘orientation statement’ letter delivered 24–48 h before the first appointment compared with standard care. The primary outcome measure was attendance at the first appointment; secondary outcomes included hospitalization, transfer of care, continuing attendance, discharge, presentation at accident and emergency and death by 1 year.
Results
Follow-up was for 763 out of 764 subjects (>99%) for primary and for 755 out of 764 subjects (98.8%) of secondary outcome data. The orientation statement significantly reduced the numbers of people failing to attend [79 out of 388 v. 101 out of 376 subjects, relative risk 0.76, 95% confidence interval (CI) 0.59–0.98, number needed to treat 16, 95% CI 10–187].
Conclusions
Prompting people to go to psychiatric out-patient clinics for the first time encourages them to attend. Pragmatic trials within a busy working environment are possible and informative.
It has recently been suggested that auditory hallucinations are the result of a criterion shift when deciding whether or not a meaningful signal has emerged. The approach proposes that a liberal criterion may result in increased false-positive identifications, without additional perceptual deficit. To test this hypothesis, we devised a speech discrimination task and used signal detection theory (SDT) to investigate the underlying cognitive mechanisms.
Method
Schizophrenia patients with and without auditory hallucinations and a healthy control group completed a speech discrimination task. They had to decide whether a particular spoken word was identical to a previously presented speech stimulus, embedded in noise. SDT was used on the accuracy data to calculate a measure of perceptual sensitivity (Az) and a measure of response bias (β). Thresholds for the perception of simple tones were determined.
Results
Compared to healthy controls, perceptual thresholds were higher and perceptual sensitivity in the speech task was lower in both patient groups. However, hallucinating patients showed increased sensitivity to speech stimuli compared to non-hallucinating patients. In addition, we found some evidence of a positive response bias in hallucinating patients, indicating a tendency to readily accept that a certain stimulus had been presented.
Conclusions
Within the context of schizophrenia, patients with auditory hallucinations show enhanced sensitivity to speech stimuli, combined with a liberal criterion for deciding that a perceived event is an actual stimulus.
While various conceptualizations of the link between childhood adversity and later depression have been offered, most have not accounted for the possibility that early adversity predicts continuing stress proximal to depression onset. Thus, the present study tested the possible mediating role of recent stress in the association between early adversity and depression in late adolescence.
Method
Study questions were examined in a longitudinal community sample of 705 youth who were contemporaneously assessed for early adversity exposure prior to age 5 years, chronic and episodic stress at age 15 years, and major depression prior to age 15 years and between 15 and 20 years.
Results
Total youth stress burden at age 15 years mediated the effect of early adversity on depression between ages 15 and 20 years, and none of the observed relationships were moderated by onset of depression prior to age 15 years.
Conclusions
These findings suggest that continued stress exposure proximal to depression onset largely accounts for the association between early adversity and depression in late adolescence. Intervention should thus focus on disrupting the continuity of stressful conditions across childhood and adolescence. Future studies of the neurobiological and psychosocial mechanisms of the link between early experiences and depression should explore whether the effects of early experiences are independent of continuing adversity proximal to depressive onset.
Patients with schizophrenia are at increased risk of being victims of violent and non-violent crimes. We have determined how the experience of crime and subjective feelings of safety differ between urban and rural residential areas.
Method
We analysed data from the European Schizophrenia Cohort (EuroSC), a 2-year follow-up study of 1208 patients in the UK, France and Germany. Subjective safety and a history of victimhood were elicited with Lehman's Quality of Life Inventory. Regression models adjusted the effects of living environment for country, education, employment, financial situation, drug and alcohol abuse, criminal arrests and the level of schizophrenic symptoms.
Results
Ten per cent of patients were victims of violent and 19% of non-violent crimes. There was no significant relationship between victim status and residential area. However, subjective safety was clearly worse in cities than in rural areas. Aspects of objective and subjective safety were related to different factors: being the victim of violence was most strongly associated with alcohol and drug abuse and with criminal arrests of the patients themselves, whereas impaired subjective safety was most strongly associated with poverty and victimhood experience.
Conclusions
Although urban living was not associated with increased objective threats to their security, patients did feel more threatened. Such stress and anxiety can be related to concepts of social capital, and may contribute unfavourably to the course of the illness, reflecting the putative role of appraisal in cognitive models of psychosis. Securing patients’ material needs may provide a way to improve subjective safety.
The ACE project involved 62 participants with a first episode of psychosis randomly assigned to either a cognitive behaviour therapy (CBT) intervention known as Active Cognitive Therapy for Early Psychosis (ACE) or a control condition known as Befriending. The study hypotheses were that: (1) treating participants with ACE in the acute phase would lead to faster reductions in positive and negative symptoms and more rapid improvement in functioning than Befriending; (2) these improvements in symptoms and functioning would be sustained at a 1-year follow-up; and (3) ACE would lead to fewer hospitalizations than Befriending as assessed at the 1-year follow-up.
Method
Two therapists treated the participants across both conditions. Participants could not receive any more than 20 sessions within 14 weeks. Participants were assessed by independent raters on four primary outcome measures of symptoms and functioning: at pretreatment, the middle of treatment, the end of treatment and at 1-year follow-up. An independent pair of raters assessed treatment integrity.
Results
Both groups improved significantly over time. ACE significantly outperformed Befriending by improving functioning at mid-treatment, but it did not improve positive or negative symptoms. Past the mid-treatment assessment, Befriending caught up with the ACE group and there were no significant differences in any outcome measure and in hospital admissions at follow-up.
Conclusions
There is some preliminary evidence that ACE promotes better early recovery in functioning and this finding needs to be replicated in other independent research centres with larger samples.
A number of scales are used to estimate the severity of depression. However, differences between self-report and clinician rating, multi-dimensionality and different weighting of individual symptoms in summed scores may affect the validity of measurement. In this study we examined and integrated the psychometric properties of three commonly used rating scales.
Method
The 17-item Hamilton Depression Rating Scale (HAMD-17), the Montgomery–Asberg Depression Rating Scale (MADRS) and the Beck Depression Inventory (BDI) were administered to 660 adult patients with unipolar depression in a multi-centre pharmacogenetic study. Item response theory (IRT) and factor analysis were used to evaluate their psychometric properties and estimate true depression severity, as well as to group items and derive factor scores.
Results
The MADRS and the BDI provide internally consistent but mutually distinct estimates of depression severity. The HAMD-17 is not internally consistent and contains several items less suitable for out-patients. Factor analyses indicated a dominant depression factor. A model comprising three dimensions, namely ‘observed mood and anxiety’, ‘cognitive’ and ‘neurovegetative’, provided a more detailed description of depression severity.
Conclusions
The MADRS and the BDI can be recommended as complementary measures of depression severity. The three factor scores are proposed for external validation.
Hypersensitivity to electromagnetic fields (EMF) is frequently claimed to be linked to a variety of non-specific somatic and neuropsychological complaints. Whereas provocation studies often failed to demonstrate a causal relationship between EMF exposure and symptom formation, recent studies point to a complex interplay of neurophysiological and cognitive alterations contributing to symptom manifestation in electromagnetic hypersensitive patients (EHS). However, these studies have examined only small sample sizes or have focused on selected aspects. Therefore this study examined in the largest sample of EHS EMF-specific cognitive correlates, discrimination ability and neurobiological parameters in order to get further insight into the pathophysiology of electromagnetic hypersensitivity.
Method
In a case-control design 89 EHS and 107 age- and gender-matched controls were included in the study. Health status and EMF-specific cognitions were evaluated using standardized questionnaires. Perception thresholds following single transcranial magnetic stimulation (TMS) pulses to the dorsolateral prefrontal cortex were determined using a standardized blinded measurement protocol. Cortical excitability parameters were measured by TMS.
Results
Discrimination ability was significantly reduced in EHS (only 40% of the EHS but 60% of the controls felt no sensation under sham stimulation during the complete series), whereas the perception thresholds for real magnetic pulses were comparable in both groups (median 21% versus 24% of maximum pulse intensity). Intra-cortical facilitation was decreased in younger and increased in older EHS. In addition, typical EMF-related cognitions (aspects of rumination, symptom intolerance, vulnerability and stabilizing self-esteem) specifically differentiated EHS from their controls.
Conclusions
These results demonstrate significant cognitive and neurobiological alterations pointing to a higher genuine individual vulnerability of electromagnetic hypersensitive patients.