Pain insensitivity in schizophrenia: trait or state marker?

Pre-emptive ice pack cryotherapy for reducing pain caused by long-acting deltoid injectable antipsychotic treatment: A single-center open-label study

PURPOSE

This empirical study aims to investigate the efficacy of pre-emptive cryotherapy in reducing pain that is caused by the deltoid intramuscular (IM) injection of long-acting injectable (LAI) antipsychotics in clinical settings.

PATIENTS AND METHODS

This study included 29 outpatients receiving LAI antipsychotic treatment. The evaluations of pain during (1) the usual procedure (control), (2) pre-emptive use of ice pack cryotherapy (pre-cooling), and (3) pre-emptive use of a room-temperature ice pack (pre-touching) were conducted using a numerical rating scale (NRS) for comparison. All patients were administered with LAI antipsychotics via deltoid IM. Furthermore, the results of the Positive and Negative Symptom Scale (PANSS), clinical global impressions (CGI) scale, and Global Assessment of Functioning (GAF) scale that were administered during the control procedure were evaluated.

RESULTS

The median NRS pain scores during the IM injection of LAI antipsychotics were 4.0 (3.0-5.0), 2.0 (1.0-3.0), and 3.0 (2.5-6.0) for the control, pre-cooling, and pre-touching conditions, indicating a significant difference (p = 6.0 × 10-6). The NRS pain scores for the pre-cooling condition were significantly lower than those for the control and pre-touching conditions (p = 2.5 × 10-5 and 6.7 × 10-5, respectively). No significant correlation was observed between the NRS pain scores for the control condition and the PANSS, CGI scale, or GAF scale scores. Furthermore, no adverse events were recorded during the study period.

CONCLUSION

Pain during the deltoid IM injection of LAI antipsychotics was found to be reduced by pre-emptive skin cooling. To date, this is the first study to confirm the effectiveness of pre-emptive cryotherapy for relieving such pain in clinical situations.

Case report: C1/2 rotational instability progressing to extreme subaxial hyperkyphosis in an adolescent with severe catatonia

Introduction

Autism spectrum disorder (ASD) is characterized by deficits in social communication, repetitive behaviors, and can be accompanied by a spectrum of psychiatric symptoms, such as schizophrenia and catatonia. Rarely, these symptoms, if left untreated, can result in spinal deformities.

Research question and case description

This case report details the treatment of a 16-year-old male ASD patient with catatonic schizophrenia and mutism, presenting with neck pain, left-rotated torticollis, and fever. MRI revealed atlantoaxial rotational instability and spinal cord compression from a dislocated dens axis. After inconclusive biopsies, empirical antibiotics, hard collar and halo fixation treatment, persistent instability necessitated C1/2 fusion. The ongoing catatonia was addressed with electroconvulsive therapy. Concurrently, he developed severe subaxial hyperkyphosis. The report examines the decision-making between conservative and surgical management for an adolescent with significant psychiatric comorbidity and progressive spinal symptoms against a backdrop of uncertain etiology.

Materials and methods

A case report and review of the literature.

Results

Posterior C1-C7 stabilization was successfully executed, effectively restoring cervical sagittal alignment, which was maintained throughout a two-year follow-up. Concurrently, the catatonia resolved.

Discussion and conclusion

To our knowledge, this is the third reported case of severe cervical deformity associated with fixed posture in a psychiatric patient. This case report emphasizes the critical importance of multidisciplinary collaboration in managing the interplay between neuropsychiatric disorders and severe spinal deformities. It showcases the practicality and efficacy of surgical intervention for persistent cervical deformity in pediatric schizophrenia patients, highlighting the necessity for a comprehensive risk-benefit analysis.

Severe mental illness and palliative care: patient semistructured interviews

OBJECTIVES

To explore perceptions, experiences and expectations with respect to palliative care of patients with severe mental illness (SMI) and an incurable, life-limiting chronic illness.

METHODS

Face-to-face semistructured interviews were conducted with 12 patients (10 of them living in a mental healthcare institution) with severe mental and physical health issues in the Netherlands. A semistructured interview guide was used to elicit perceptions of, experiences with and expectations regarding palliative care. Data were analysed using inductive content analysis.

RESULTS

Analysis of the data revealed eight categories: perceptions on health and health issues, coping with illness and symptoms, experiences with and wishes for current healthcare, contact with relatives and coresidents, experiences with end of life of relatives and coresidents, willingness to discuss end of life and death, wishes and expectations regarding one's own end of life and practical aspects relating to matters after death. These categories were clustered into two separate themes: current situation and anticipation of end of life. Interviewees with SMI appeared not accustomed to communicate about end-of-life issues, death and dying due to their life-threatening illness. They tended to discuss only their current situation and, after further exploration of the researcher, the terminal phase of life. They seemed not engaged in their future palliative care planning.

CONCLUSIONS

Findings of this study highlight inadequacies in advance care planning for patients with SMI. Results suggest using values, current and near wishes, and needs as a starting point for establishing a gradual discussion concerning goals and preferences for future medical and mental treatment and care.

Risks of complicated acute appendicitis in patients with psychiatric disorders

BACKGROUND

Acute appendicitis often presents with vague abdominal pain, which fosters diagnostic challenges to clinicians regarding early detection and proper intervention. This is even more problematic with individuals with severe psychiatric disorders who have reduced sensitivity to pain due to long-term or excessive medication use or disturbed bodily sensation perceptions. This study aimed to determine whether psychiatric disorder, psychotropic prescription, and treatment compliance increase the risks of complicated acute appendicitis.

METHODS

The diagnosis records of acute appendicitis from four university hospitals in Korea were investigated from 2002 to 2020. A total of 47,500 acute appendicitis-affected participants were divided into groups with complicated and uncomplicated appendicitis to determine whether any of the groups had more cases of psychiatric disorder diagnoses. Further, the ratio of complicated compared to uncomplicated appendicitis in the mentally ill group was calculated regarding psychotropic dose, prescription duration, and treatment compliance.

RESULTS

After adjusting for age and sex, presence of psychotic disorder (odds ratio [OR]: 1.951; 95% confidence interval [CI]: 1.218-3.125), and bipolar disorder (OR: 2.323; 95% CI: 1.194-4.520) was associated with a higher risk of having complicated appendicitis compared with absence of psychiatric disorders. Patients who are taking high-daily-dose antipsychotics, regardless of prescription duration, show high complicated appendicitis risks; High-dose antipsychotics for < 1 year (OR: 1.896, 95% CI: 1.077-3.338), high-dose antipsychotics for 1-5 years (OR: 1.930, 95% CI: 1.144-3.256). Poor psychiatric outpatient compliance was associated with a high risk of complicated appendicitis (OR: 1.664, 95% CI: 1.014-2.732).

CONCLUSIONS

This study revealed a close relationship in the possibility of complicated appendicitis in patients with severe psychiatric disorders, including psychotic and bipolar disorders. The effect on complicated appendicitis was more remarkable by the psychiatric disease entity itself than by psychotropic prescription patterns. Good treatment compliance and regular visit may reduce the morbidity of complicated appendicitis in patients with psychiatric disorders.

Study on clinical characteristics and related factors of schizophrenic patients with intestinal obstruction

BACKGROUND

There are still few studies on the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction. Our aim is to explore the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction.

METHODS

This study focused on schizophrenia patients with intestinal obstruction who were hospitalized in the psychiatric department of a hospital in Wuhan from January 2007 to December 2020 as the main research object. We intend to retrospectively analyze the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction.

RESULTS

In the 1937 persons with schizophrenia included in this study, 97 patients were complicated with intestinal obstruction, and the incidence was 5.01%.The results of the study showed that patients with age ≥ 60 years old, visiting time ≥ 24 h, hospital stay ≥ 90 days, history of abdominal surgery, course of disease ≥ 5 years, male, and patients with cardiovascular and cerebrovascular diseases are prone to intestinal obstruction; Logistic multiple regression analysis showed that the related risk factors of schizophrenia patients with intestinal obstruction mainly included the patient's age, visiting time, length of hospital stay, history of abdominal surgery, course of disease and gender.

CONCLUSION

The older the age, the longer the hospital stay, the longer the course of the disease, the history of previous surgery, and the male schizophrenia who do not see a doctor within 24 h of the onset, the risk of intestinal obstruction is higher, and it is easy to be misdiagnosed and even life-threatening.

Antipsychotic-Induced Constipation: A Review of the Pathogenesis, Clinical Diagnosis, and Treatment

Antipsychotic-induced gastrointestinal hypomotility and, in particular, its manifestation of constipation are common adverse effects in patients with schizophrenia in clinical practice. Serious complications of antipsychotic-induced constipation include ileus, ischaemic bowel disease, colon perforation, aspiration pneumonia, and bacterial septicaemia, which can be life threatening if left untreated, especially in patients prescribed clozapine. The aim of this paper is to review the latest research on the epidemiology, clinical examination methods, pathophysiology, and treatment options and preventive measures for antipsychotic-induced constipation. While clinicians are normally aware of the overall side effects caused by antipsychotics, constipation is often an under-recognized condition despite its relatively high incidence and its impact on daily living. The incidence of constipation differs among individual antipsychotics, but more than 50% of patients prescribed antipsychotics suffer from constipation. Limited fluid intake, poor dietary habits, and a sedentary lifestyle can also worsen constipation. The mechanisms of antipsychotic-induced constipation may be antagonism of cholinergic, histaminergic, and serotonergic receptors, with both parent drug and metabolite(s) contributing to the effects on gastrointestinal motility. Numerous methods, mainly divided into scale evaluations and objective examinations, are applied to evaluate antipsychotic-induced constipation; however, objective examinations have a greater ability to identify cases of gastrointestinal hypomotility since there is often an under-reporting of symptoms in subjective reporting and scale evaluation due to a higher pain threshold, an inability to express pain sensations, and a lack of symptom awareness in these patients. Antipsychotic drug-induced constipation should be closely monitored in patients receiving these medications, with timely intervention to avoid serious gastrointestinal consequences. There is currently no consensus on the efficacy of laxatives in these patients. Further in-depth studies should explore the underlying mechanisms and devise optimal therapeutic approaches to minimize constipation during antipsychotic treatment.

Evaluation of acute and chronic nociception in subchronically administered MK-801-induced rat model of schizophrenia

Patients diagnosed with schizophrenia have been reported to exhibit atypically low pain sensitivity and to vary in their experience of chronic pain. To the best of our knowledge, there has yet to be an animal study that provides information concerning the relationship between models of schizophrenia and pain. In the present study, we investigated several distinct nociceptive behaviors in a translational rat model of schizophrenia (0. 5 mg/kg MK-801, twice a day for 7 days followed by a 7-day washout period). The presence of the expected cognitive deficit was confirmed with novel object recognition (NOR) paradigm prior to nociception testing. MK-801-treated rats with lack of novelty interest in NOR testing showed: hyposensitivity to thermal and mechanical stimuli; short-term hypoalgesia followed by augmented hyperalgesia in response to formalin-induced spontaneous nociception and increased thermal and mechanical hyperalgesia in the complete Freund's adjuvant (CFA) induced chronic pain model. In conclusion, MK-801 induced antinociception effects for thermal stimuli in rats that were consistent with the decreased pain sensitivity observed in schizophrenia patients. Additionally, the amplified biphasic response exhibited by the MK-801 group in the formalin-induced spontaneous nociception test affirms the suitability of the test as a model of acute to delayed pain transition.

Simulation and social behavior: an fMRI study of neural processing during simulation in individuals with and without risk for psychosis

Social dysfunction is a risk indicator for schizophrenia spectrum disorders, with at-risk individuals demonstrating a range of social behavior impairments. Variability in social ability may be explained by individual differences in the psychological processes of social behavior. In particular, mental simulation, the process by which an individual generates an internal representation of the thoughts or feelings of another, may explain variation in social behavior. This study investigates the neural process of simulation in healthy individuals and individuals at risk for psychosis. Using a novel fMRI pain paradigm, individuals watch videos of another person’s hand or foot experiencing pain. After each video, individuals are asked to simulate the observed painful situation on their own hand or foot. Neural activity during simulation in the somatosensory cortex was associated with real-world self-reported social behavior, such that a stronger neural response in the somatosensory cortex was associated with greater rates of positive social experiences and affective empathy across all participants. These findings suggest that the neural mechanisms that underlie simulation are important for social behavior, and may explain individual variability in social functioning in healthy and at-risk populations.

Dissecting pain processing in adolescents with Non-Suicidal Self Injury: Could suicide risk lurk among the electrodes?

Background

Although non‐suicidal self‐injury (NSSI) disorder is highly prevalent in adolescents, its relationship with pain system function and suicidality is still controversial. The present study was designed to assess the function of the nociceptive afferent pathways and the endogenous pain modulation in adolescent patients with NSSI and to longitudinally register any suicide attempt, describe its frequency and find a possible association between suicide, neurophysiological measures and psychological measures.

Methods

We enrolled 30 adolescents suffering from NSSI and 20 age‐ and gender‐matched healthy controls. Patients underwent a comprehensive psychological evaluation. Each participant underwent thermal pain thresholds of the quantitative sensory testing, laser‐evoked potential recording to study the ascending nociceptive pathway and the conditioned pain modulation testing to test the endogenous pain modulation.

Results

We found that patients with NSSI had a reduced amplitude of the N2 component of laser‐evoked potentials and an abnormal conditioned pain modulation. The amplitude of the N2 was associated with suicidal risk.

Conclusions

The deficit of the endogenous pain modulation likely depends on a saturation due to continuous pain solicitation. The strong association of a reduced amplitude of the N2 component with suicide suggests that it may serve as a possible biomarker in self‐harming adolescents.

Significance

The present study identifies the N2 component of laser‐evoked potentials as a possible neurophysiological biomarker of suicidal risk in patients with non‐suicidal self‐injury, therefore, raising the possibility for a non‐invasive test to identify subjects at higher risk of suicide among self‐harming patients.

Challenges associated with treating and preventing antipsychotic-induced constipation: considerations and cautions when prescribing novel interventions

Antipsychotic-induced constipation is a treatment-limiting side effect for patients with serious mental illness (SMI). In addition to increased risk of constipation, due to adverse medication effects, individuals diagnosed with SMI are also prone to lifestyle factors that contribute to this medical complication. The USA Food and Drug Administration (FDA) recently released enhanced warnings about the risk of serious, sometimes fatal, complications associated with constipation caused by the antipsychotic, clozapine. It is likely this heightened warning will prompt providers to seek additional means to prevent and treat antipsychotic-induced constipation, despite having no agent with FDA approval for this specific indication. Off-label prescribing of newer medications for the treatment of antipsychotic-induced constipation is associated with risks, many of which are still unknown, considering the exclusion of patients with SMI in studies measuring nonpsychiatric outcomes.

Bodily Self-Disturbances in Schizophrenia: A Comparative Study of South Korea and the USA

BACKGROUND

Bodily self-disturbances are highly salient to the phenomenology of schizophrenia (SZ) but difficult to quantify owing to the subjective nature of these experiences that challenge verbal descriptions. The Benson et al. [PsyCh J. 2019 Mar;8(1):110-21] Body Disturbances Inventory (B-BODI) provides visual aids to help participants access the frequency, distressfulness, and vividness of subjective self-experiences with good reliability and validity in North American samples. However, the concept of the self and, accordingly, the conceptualization of self-disorders are influenced by culture. Therefore, we examined self-disturbances in individuals with SZ and control (CO) participants in 2 distinct cultures.

METHODS

B-BODI was administered to South Korean and North American participants, with and without SZ. Severity of symptoms in diagnosed individuals with SZ and schizotypy in CO was assessed. We also assessed perceived social isolation and mood in all participants.

RESULTS

Endorsement and frequency of bodily self-disturbances in SZ were similar in both cultures. In contrast, there were significant cultural differences in the degree of distress and vividness of self-disturbances. Bodily self-disturbances were experienced as more vivid and distressing to Americans than Koreans, regardless of diagnosis. For both cultures, B-BODI scores were associated with positive, but not negative, symptoms in SZ. For CO, elevated schizotypy was associated with B-BODI scores. Mood and loneliness were not associated with B-BODI scores.

CONCLUSION

SZ reported overall increased levels of bodily self-disturbances compared with CO, regardless of culture. However, there were cultural differences in one's emotional reaction to these experiences. Americans were more distressed by self-disturbances and experienced them more vividly than Koreans. These findings suggest that Americans may be less accepting of anomalous bodily self-experiences relative to Koreans. Last, B-BODI appears to be a useful tool for future cross-cultural studies of SZ phenomenology.

A modality-specific dysfunction of pain processing in schizophrenia

Clinical observations showed that schizophrenia (SCZ) patients reported little or no pain under various conditions that are commonly associated with intense painful sensations, leading to a higher risk of morbidity and mortality. However, this phenomenon has received little attention and its underlying neural mechanisms remain unclear. Here, we conducted two experiments combining psychophysics, electroencephalography (EEG), and functional magnetic resonance imaging (fMRI) techniques to investigate neural mechanisms of pain insensitivity in SCZ patients. Specifically, we adopted a stimulus-response paradigm with brief stimuli of different sensory modalities (i.e., nociceptive, non-nociceptive somatosensory, and auditory) to test whether pain insensitivity in SCZ patients is supra-modal or modality-specific, and used EEG and fMRI techniques to clarify its neural mechanisms. We observed that perceived intensities to nociceptive stimuli were significantly smaller in SCZ patients than healthy controls, whereas perceived intensities to non-nociceptive somatosensory and auditory stimuli were not significantly different. The behavioral results were confirmed by stimulus-evoked brain responses sampled by EEG and fMRI techniques, thus verifying the modality-specific nature of the modulation of nociceptive information processing in SCZ patients. Additionally, significant group differences were observed in the spectral power of alpha oscillations in prestimulus EEG and the seed-based functional connectivity in resting-state fMRI (seeds: the thalamus and periaqueductal gray that are key nodes in ascending and descending pain pathways respectively), suggesting a possible contribution of cortical-subcortical dysfunction to the phenomenon. Overall, our study provides insight into the neural mechanisms of pain insensitivity in SCZ and highlights a need for systematic assessments of their pain-related diseases.

Increased risk of perforated appendicitis in patients with schizophrenia and dementia: A population-based case-control study

Previous studies have suggested that patients with psychotic or mental disorders are relatively pain insensitive, resulting in difficulties in the diagnosis of acute intra-abdominal diseases requiring emergency surgeries. We aimed to evaluate whether central nervous system (CNS) or mental disorders are associated with perforated appendicitis in patients with acute appendicitis.We conducted a population-based case-control study using Taiwan's National Health Insurance Research database. Patients aged >18 years who had been hospitalized with a diagnosis of acute appendicitis between 2000 and 2013 were identified. After 1:1 matching for age and sex, 2792 patients with perforated appendicitis (case group) and 2792 patients with nonperforated appendicitis (control group) were included. CNS disorders, mental disorders, pain control medication, and several comorbidities were analyzed for the odds of appendiceal perforation with 95% confidence interval (CI) using the multivariable logistic regression model.Schizophrenia and dementia were associated with a high risk of appendiceal rupture in patients with acute appendicitis, with an adjusted odds ratio of 2.01 for dementia (95% CI: 1.19-3.39, P = .009) and 4.8 for schizophrenia (95% CI: 1.62-14.19, P = .005). Other factors, such as other CNS disorders, comorbidities, and pain control medication, were not associated with the risk of perforated appendicitis.Dementia and schizophrenia are associated with perforated appendicitis in patients with acute appendicitis. This might be owing to altered pain perception, difficult symptom expression, and delayed hospitalization. Further studies are still needed to determine the underlying mechanism and confirm the causality.

Linking brain structure and activation in anterior insula cortex to explain the trait empathy for pain

The ability to perceive, understand, and react to the feelings of others' pain is referred to as empathy for pain which is composed of two components, affective‐perceptual empathy and cognitive‐evaluative empathy. Recent reviews on the neural mechanisms of empathetic pain showed the anterior insula (AI) cortex as a core circuit for empathy. However, little is known about the modulation of brain anatomy and empathic responses by trait measures of empathy (trait empathy). Thus, we investigated whether individual variation in the personality trait of empathy is associated with individual variation in the structure of specific brain regions using voxel‐based morphometry (VBM). We further investigated the relationship between the trait empathy and the activity of the same regions using state measures of empathy for pain in a trial‐by‐trial fashion in the given situation. VBM analysis indicated a small but significant negative relationship between trait empathy and gray matter volume in the bilateral AI. Functional MRI study further demonstrated that experimentally induced activity of the bilateral AI during state empathy for pain was also correlated with trait empathy. An asymmetry exists between the right and left AI between the affective and cognitive empathy. The right AI was found to be involved in the affective‐perceptual form of empathy and the left AI was active in cognitive‐evaluative forms of empathy. The interindividual differences in trait empathy may be reflected both in the state empathy and more stable brain structure difference.

Bodily self-disturbance in schizophrenia-spectrum populations: Introducing the Benson et al. Body Disturbances Inventory (B-BODI)

Anomalous or weakened sense of self was central to early theories of schizophrenia. Recent studies have also documented disturbances in body ownership and increased susceptibility for dissociative experiences, such as the out-of-body experience in individuals with schizophrenia, but further research is necessary to clarify components of bodily self-disturbances in the schizophrenia spectrum, and the stability of these experiences over time. With respect to methodology, self-disturbances research in schizophrenia tends to rely exclusively on verbal self-report questionnaires and interviews. Given that individuals with schizophrenia suffer from language and communication difficulties, verbal self-report measures may be insufficient. To bridge this gap, we have developed a new picture-based instrument, the Benson et al. Body Disturbances Inventory (B-BODI), designed to quantify bodily self-disturbances with respect to the frequency and vividness of these experiences, as well as the degree of distress associated with them. Drawings that depicted different aspects of aberrant bodily self-experiences were presented with accompanying captions. Participants were asked to indicate the frequency, vividness, and distressfulness of the experience captured by the picture using a 5-point scale. Individuals with schizophrenia, older healthy controls, and college students participated in two alternative versions of the B-BODI. Participants were also asked to complete a battery of established questionnaires that probed psychosis proneness and a range of self, body, and perceptual aberrations. The results suggest that the B-BODI is a useful tool that accurately captures bodily self-disturbances and has the potential to predict psychosis risk in healthy young individuals. Furthermore, anomalous self-disturbances seem to be relatively stable across time in individuals with chronic schizophrenia.

Physical health status of older adults with severe mental illness: The PHiSMI-E cohort study

The objective was to use various somatic parameters as basis for investigating the physical health of older adults with severe mental illnesses (SMI). A cross-sectional study design is performed by using baseline data from the Physical Health in SMI-elderly (PHiSMI-E) study. Data were collected using the Nursing Monitoring of Somatic Status and Lifestyle - Mental Health instrument in adults aged over 60 with SMI in a large Dutch mental health institute. Ninety-nine elderly SMI patients were included. Somatic comorbidity (84.8%), use of somatic medication (77.7%) and polypharmacy (67.7%) were prevalent. Extrapyramidal symptoms were experienced by 51% of patients, mainly in the subgroup with psychotic disorders (75.6%). Unhealthy diet was reported in 16.2%, obesity in 27.3%, and physical inactivity in 57.6%. Fatigue (67.7%) and dry mouth (66.6%) were the commonest reported physical symptoms. Mean VAS score (scale 0-10) indicating participants' self-perceived physical health was 6.7 (SD ± 1.6). After division of the total patient group into tertiles based on the VAS scores, the lowest tertile was characterized by less physical activity, unhealthier diet, more use of medication, more fatigue, somnolence, and inner agitation. In conclusion, impaired physical health status was common in these older patients with SMI. Although they had more psychiatric and somatic comorbidity than adult SMI patients described in the literature, they had a healthier lifestyle. To reduce morbidity and premature mortality in these frail patients, it is essential that healthcare providers are aware of the high prevalence of somatic comorbidity and symptoms, and of their interactions with the psychiatric disorders. This study improves our understanding of differences in vulnerability factors of older patients with SMI. The (early) detection of somatic comorbidities may improve long-term health outcomes of these patients.

Epidemiology of pain and relation to psychiatric disorders

Chronic pain is a common pain condition. Some psychiatric disorders, such as anxiety and depression, are also common in the general population. Epidemiological studies found that some psychiatric disorders are more commonly found among persons with chronic pain (e.g., headache, back pain) than those without chronic pain. Why those psychiatric disorders co-occur with chronic pain, however, is not well understood. Further, studies demonstrated that some psychiatric disorders, such as depression, increase the risk of chronic pain as well as its persistence. It is also recognized that chronic pain has a negative impact on the persistence of psychiatric disorders. The observations from clinical studies suggest that chronic pain is not a common comorbidity among individuals with other psychiatric disorders, such as dementia and schizophrenia. It is not clear if this is a consequence of any specific biological mechanism, or methodology problems in the studies. This paper provides an overview on the distribution of chronic pain and psychiatric disorders, followed by a review of studies that have demonstrated the association between psychiatric disorders and chronic pain.

Self-reported pain in patients with schizophrenia. Results from the national first-step FACE-SZ cohort

INTRODUCTION

Little is known about perception of physical pain in schizophrenia (SZ). Some studies have suggested that patients with SZ may have an increased pain threshold, while others have suggested that patients with SZ may suffer from undetected and untreated high physical pain levels. The objectives of this study were (i) to investigate the prevalence of self-reported physical pain in stabilized SZ subjects, and (ii) to determine whether physical pain was associated with psychiatric characteristics and somatic comorbidities (iii) to determine whether antidepressants and benzodiazepine administration were associated with lower self-reported pain.

METHOD

468 community-dwelling stable SZ subjects (73% men, mean aged 32 years) were recruited in the Schizophrenia Expert Center national network. Patients with moderate to extreme pain, assessed with the EQ5D-5L questionnaire, were classified as belonging to the "pain group".

RESULTS

104 (22.2%) reported moderate to extreme pain levels. In multivariate analysis, pain has been associated with headache (OR = 2.63 [1.04-6.63], p = 0.04), higher anxiety (OR = 1.61 [1.18-2.21], p = 0.003), higher current depressive symptoms (OR = 1.09 [1.01-1.17], p = 0.03), history of childhood trauma (1.03 [1.01-1.06], p = 0.01) and older age (OR = 1.04 [1.01-1.07], p = 0.03), independently of current psychotic severity, sociodemographic variables, antipsychotic, antidepressant and benzodiazepine treatments. No association with addictive behaviors or illness characteristics has been found.

CONCLUSION

The present findings suggest that community-dwelling SZ outpatients report a high rate of self-reported physical pain, associated with headache, depression and anxiety and history of childhood trauma. Physical pain should be systematically assessed and specifically treated, when needed, in patients with SZ.

Glutamatergic Response to Heat Pain Stress in Schizophrenia

Regulation of stress response involves top-down mechanisms of the frontal-limbic glutamatergic system. As schizophrenia is associated with glutamatergic abnormalities, we hypothesized that schizophrenia patients may have abnormal glutamatergic reactivity within the dorsal anterior cingulate cortex (dACC), a key region involved in perception of and reaction to stress. To test this, we developed a somatic stress paradigm involving pseudorandom application of safe but painfully hot stimuli to the forearm of participants while they were undergoing serial proton magnetic resonance spectroscopy to measure changes in glutamate and glutamine levels in the dACC. This paradigm was tested in a sample of 21 healthy controls and 23 patients with schizophrenia. Across groups, glutamate levels significantly decreased following exposure to thermal pain, while ratio of glutamine to glutamate significantly increased. However, schizophrenia patients exhibited an initial increase in glutamate levels during challenge that was significantly different from controls, after controlling for heat pain tolerance. Furthermore, in patients, the acute glutamate response was positively correlated with childhood trauma (r = .41, P = .050) and inversely correlated with working memory (r = -.49, P = .023). These results provide preliminary evidence for abnormal glutamatergic response to stress in schizophrenia patients, which may point toward novel approaches to understanding how stress contributes to the illness.

The Insula and Taste Learning

The sense of taste is a key component of the sensory machinery, enabling the evaluation of both the safety as well as forming associations regarding the nutritional value of ingestible substances. Indicative of the salience of the modality, taste conditioning can be achieved in rodents upon a single pairing of a tastant with a chemical stimulus inducing malaise. This robust associative learning paradigm has been heavily linked with activity within the insular cortex (IC), among other regions, such as the amygdala and medial prefrontal cortex. A number of studies have demonstrated taste memory formation to be dependent on protein synthesis at the IC and to correlate with the induction of signaling cascades involved in synaptic plasticity. Taste learning has been shown to require the differential involvement of dopaminergic GABAergic, glutamatergic, muscarinic neurotransmission across an extended taste learning circuit. The subsequent activation of downstream protein kinases (ERK, CaMKII), transcription factors (CREB, Elk-1) and immediate early genes (c-fos, Arc), has been implicated in the regulation of the different phases of taste learning. This review discusses the relevant neurotransmission, molecular signaling pathways and genetic markers involved in novel and aversive taste learning, with a particular focus on the IC. Imaging and other studies in humans have implicated the IC in the pathophysiology of a number of cognitive disorders. We conclude that the IC participates in circuit-wide computations that modulate the interception and encoding of sensory information, as well as the formation of subjective internal representations that control the expression of motivated behaviors.

Perforated appendicitis in patients with schizophrenia: a retrospective cohort study

OBJECTIVE

Altered pain sensitivity may affect the outcome of appendicitis in patients with schizophrenia. We aimed to compare the prevalence of perforation in appendicitis between patients with and without schizophrenia.

DESIGN

Retrospective cohort study with random matching.

SETTING

A single tertiary medical centre in Japan.

PARTICIPANTS

From 1985 to 2013, 1821 cases of appendicitis requiring appendectomy were collected. Patients with schizophrenia and a cohort of randomly selected control subjects without schizophrenia who underwent appendectomy were identified.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the rate of perforated appendicitis in patients with and without schizophrenia. Secondary outcome was the odds of perforated appendicitis by different clinical factors.

RESULTS

62 patients with schizophrenia and randomly sampled 200 non-schizophrenic patients were compared. The prevalence of perforation was 53% in patients with schizophrenia versus 17% in controls (p<0.0001). The adjusted OR for perforation were 4.87 (95% CI: 2.33 to 10.2) for schizophrenia, 3.35 (95% CI 1.51 to 7.45) for age >55 years and 2.18 (95% CI: 1.12 to 4.27) for delayed presentation.

CONCLUSION

Appendiceal perforation was more frequent in patients with schizophrenia than controls, which may be partly attributable to delayed presentation and altered responses to pain.

Pharmacological treatment for antipsychotic-related constipation

BACKGROUND

Antipsychotic-related constipation is a common and serious adverse effect, especially for people taking clozapine. Clozapine has been shown to impede gastrointestinal motility, leading to constipation, and has been reported in up to 60% of patients receiving clozapine. In rare cases, complications can be fatal. Appropriate laxatives should be prescribed to treat constipation in people taking antipsychotics, but there is a lack of guidance on the comparative effectiveness and harms of different agents in this population. An understanding of the effectiveness and safety of treatment for antipsychotic-related constipation is important for clinicians and patients alike.

OBJECTIVES

To evaluate the effectiveness and safety of pharmacologic treatment (versus placebo or compared against another treatment) for antipsychotic-related constipation (defined as constipated patients of any age, who are treated with antipsychotics, regardless of dose, in which constipation is considered to be an antipsychotic-related side effect).

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Trials Register (15 June 2015), which is based on regular searches of MEDLINE, Embase, CINAHL, BIOSIS, AMED, PubMed, PsycINFO, and registries of clinical trials, grey literature, and conference proceedings. There are no language, date, document type, or publication status limitations for inclusion of records in this register. We also handsearched bibliographies and contacted relevant authors for additional information.

SELECTION CRITERIA

We included all published and unpublished randomised controlled trials (RCTs) investigating the efficacy of pharmacological treatments in patients with antipsychotic-related constipation. Pharmacological treatments included laxatives and other medicines that could reasonably be used to combat constipation in this population (e.g. anticholinergic agents, like bethanecol).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from all included studies and assessed trials for risk of bias. A third author reviewed 20% of trials. We analysed dichotomous data using relative risks (RR) and the 95% confidence intervals (CI). We assessed risk of bias for included studies and used GRADE to create a 'Summary of findings' table. We discussed any disagreement, documented decisions, and attempted to contact study authors when necessary.

MAIN RESULTS

We identified two relevant Chinese studies (N = 480) that contributed data to this review. Both studies were over ten years old and poorly reported, lacking descriptions of contemporary CONSORT reporting prerequisites, such as sequence generation, allocation concealment, blinding, participant flow, how the sample size was determined, or how outcomes were measured. The studies also did not report trial registration, pre-specified protocols, consent processes, ethical review, or funding source. We were unsuccessful in making contact with the authors to clarify the missing details. We classified both studies as having an overall high risk of bias.One study compared glycerol suppository with the traditional Chinese medicine (TCM) approaches of tuina massage and acupuncture. Compared to tuina massage, glycerol laxative was less effective in relieving constipation at both two days after treatment (1 RCT; N = 120; RR 2.88, 95% CI 1.89 to 4.39; very low-quality evidence), and three days (1 RCT; N = 120; RR 4.80, CI 1.96 to 11.74, very low-quality evidence). Favourable results were also seen for acupuncture at two days (1 RCT; N = 120; RR 3.50; 95% CI 2.18 to 5.62; very low-quality evidence), and at three days (1 RCT; N = 120; RR 8.00, 95% CI 2.54 to 25.16; very low-quality evidence).The other study compared mannitol, an osmotic laxative, with rhubarb soda or phenolphthalein. Mannitol was more effective than rhubarb soda or phenolphthalein in trelieving constipation within 24 hours of treatment (1 RCT; N = 240; RR 0.07; 95% CI 0.02 to 0.27, very low-quality evidence).No data were reported for our other important outcomes: need for rescue medication, bowel obstruction (a complication of antipsychotic-related constipation), quality of life, adverse events, leaving the study early, and economic costs.

AUTHORS' CONCLUSIONS

We had hoped to find clinically useful evidence appraising the relative merits of the interventions routinely used to manage antipsychotic-related constipation, a common and potentially serious adverse effect of the use of these drugs. The results were disappointing. There were no data comparing the common pharmacological interventions for constipation, such as lactulose, polyethylene glycol, stool softeners, lubricant laxatives, or of novel treatments such as linaclotide. Data available were very poor quality and the trials had a high risk of bias. Data from these biased studies suggested that mannitol, an osmotic laxative, was more effective than rhubarb soda and phenolphthalein in relieving constipation, and a two-week course of glycerol suppositories was less effective than the TCM approaches of tuina massage and acupuncture.Overall, there is insufficient trial-based evidence to assess the effectiveness and safety of pharmacological interventions for treating antipsychotic-related constipation, due to limited, poor quality data (few studies with high risk of bias and no meta-analyses). The methodological limitations in the included studies were obvious, and any conclusions based on their results should be made with caution. Methodologically rigorous RCTs evaluating interventions for treating antipsychotic-related constipation are needed.

Pain-processing abnormalities in bipolar I disorder, bipolar II disorder, and schizophrenia: A novel trait marker for psychosis proneness and functional outcome?

OBJECTIVES

Overlapping neural system dysfunctions, mainly involving the secondary somatosensory cortex (S2), the anterior cingulate cortex (ACC) and the anterior insular cortex (AIC), seem to be related to both pain-perception abnormalities and psychotic symptoms in schizophrenia (SCZ) and bipolar disorder (BD). Laser-evoked potentials (LEPs) were used to investigate pain-perception and central pain-processing abnormalities in SCZ, bipolar I disorder (BD-I), and bipolar II disorder (BD-II), and to evaluate their relationship with history of psychosis, and social-cognitive and functional impairments.

METHODS

Twenty patients with SCZ, 17 patients with BD-I, and 21 patients with BD-II who were all under similar pharmacological treatment underwent clinical, functional, and neuro-psychological assessment. LEPs were analyzed in patients and 19 healthy subjects (HS). LEPs elicit responses reflecting the activity of the S2 (N1 wave) and the ACC/AIC cortices (N2/P2 complex). A four-group ANOVA was conducted between patients and HS to compare pain-perceptive thresholds (PThs), N1, and N2/P2-LEP components.

RESULTS

Compared to HS: (i) patients with SCZ showed pain-processing and pain-perception abnormalities, as revealed by significantly higher PTh (P<.01), and lower N1 (P<.01) and N2/P2 (P<.01) amplitudes, (ii) patients with BD-I showed only pain-processing abnormalities, as revealed by significantly lower N1 (P<.05) and N2 (P<.01) amplitudes; and patients with BD-II did not differ for any of the LEP variables investigated. N1 and N2 amplitudes negatively correlated to history of psychosis (P<.01), social-cognition (P<.05), and real-world functioning (P<.01) measures in the whole group of patients.

CONCLUSIONS

To the best of our knowledge, this is the first study comparing central pain processing in patients with SCZ, BD-I, and BD-II. Our results suggest that pain-processing abnormalities may represent a novel locus of interest for research investigating trait markers of the psychosis spectrum.

Markedly Reduced Thermal Pain Perception in a Schizoaffective Patient with Tardive Dyskinesia

Several case reports have described stories of schizophrenia patients reporting no discomfort in response to several medical conditions which normally elicit pain. Comparatively, experimental studies performed on pain perception in schizophrenia have not documented hypoalgesic responses that are as frank as those reported in these clinical cases. Here, we report the case of a female patient with schizoaffective disorder, who displayed markedly reduced pain perception during an experimental heat pain paradigm. Compared to a large group of healthy volunteers that we tested in 3 previous studies using the same psychophysical procedure, the experimental temperature required to induce moderate pain was radically increased in this patient (z-score = 3.6). The patient had mild psychiatric symptoms and had insight into her symptoms. She had drug-induced dyskinetic symptoms. This case report illustrates that it is possible to observe marked reductions in pain perception in schizophrenia patients tested in experimental settings but that the phenomenon is relatively rare. Regardless of the exact nature of pain indifference in schizophrenia, it can delay diagnosis and treatment of medical problems in these patients. Future studies in the field will need to pay attention to drug-induced extrapyramidal symptoms.

Neurophysiological responses to unpleasant stimuli (acute electrical stimulations and emotional pictures) are increased in patients with schizophrenia

Patients with schizophrenia have often been described as insensitive to nociceptive signals, but objective evidence is sparse. We address this question by combining subjective behavioral and objective neurochemical and neurophysiological measures. The present study involved 21 stabilized and mildly symptomatic patients with schizophrenia and 21 control subjects. We applied electrical stimulations below the pain threshold and assessed sensations of pain and unpleasantness with rating scales, and Somatosensory Evoked Potentials (SEPs/EEG). We also measured attention, two neurochemical stress indices (ACTH/cortisol), and subjective VEPs/EEG responses to visual emotional stimuli. Our results revealed that, subjectively, patients’ evaluations do not differ from controls. However, the amplitude of EEG evoked potentials was greater in patients than controls as early as 50 ms after electrical stimulations and beyond one second after visual processing of emotional pictures. Such responses could not be linked to the stress induced by the stimulations, since stress hormone levels were stable. Nor was there a difference between patients and controls in respect of attention performance and tactile sensitivity. Taken together, all indices measured in patients in our study were either heightened or equivalent relative to healthy volunteers.

Clozapine-treated Patients Have Marked Gastrointestinal Hypomotility, the Probable Basis of Life-threatening Gastrointestinal Complications: A Cross Sectional Study

BACKGROUND

Gastrointestinal side effects are particularly common with clozapine and occur with other antipsychotics, ranging from mild constipation to fatal bowel obstruction and/or ischemia. While this adverse-effect spectrum has been attributed to 'gastrointestinal hypomotility', gastrointestinal transit times in antipsychotic-treated patients have not previously been measured, making this mechanism speculative.

METHODS

Using standardized radiopaque marker ('Metcalf') methods we established colonic transit times of antipsychotic-treated psychiatric inpatients and compared them with population normative values. We analyzed results by antipsychotic type, antipsychotic dose equivalent, anticholinergic load, duration of treatment, gender, ethnicity, and age.

OUTCOMES

For patients not prescribed clozapine, median colonic transit time was 23 h. For patients prescribed clozapine, median transit time was 104.5 h, over four times longer than those on other antipsychotics or normative values (p < 0.0001). Eighty percent of clozapine-treated patients had colonic hypomotility, compared with none of those prescribed other antipsychotics (olanzapine, risperidone, paliperidone aripiprazole, zuclopenthixol or haloperidol). In the clozapine group, right colon, left colon and rectosigmoid transit times were all markedly abnormal suggesting pan-colonic pathology. Hypomotility occurred irrespective of gender, age, ethnicity, or length of clozapine treatment. Transit times were positively correlated with clozapine plasma level (rho = 0.451, p = 0.045), but not with duration of treatment, total antipsychotic load or demographic factors.

INTERPRETATION

Clozapine, unlike the other antipsychotics examined, causes marked gastrointestinal hypomotility, as previously hypothesized. Pre-emptive laxative treatment is recommended when starting clozapine.

Schizophrenia and Suicide Attempts: Findings from a Representative Community-Based Canadian Sample

This study examined factors associated with suicide attempts among those with schizophrenia (n = 101) versus those without (n = 21,643) in a representative sample of noninstitutionalized Canadians. The lifetime prevalence of suicide attempts among persons with schizophrenia was 39.2% versus 2.8% of nonafflicted individuals. After adjusting for sociodemographics, childhood adversities, substance abuse/dependence, depression/anxiety, and chronic pain, those with schizophrenia had 6 times the odds (OR = 6.47) of attempting suicide. Among persons with schizophrenia, suicide attempts were associated with female gender (OR = 4.59), substance abuse/dependence (OR = 6.31), depression (OR = 4.93), and childhood physical abuse (OR = 5.75). Community-dwelling persons with schizophrenia appear to be at high risk for suicide attempts.

Prescription Opioid Use Among Seriously Mentally Ill Veterans Nationally in the Veterans Health Administration

Frequent prescription opioid use has been recognized as a growing problem but there have been no studies specifically among veterans with serious mental illness (SMI). National data from the Veterans Health Administration (VHA) during Fiscal Year 2012 show that VHA patients with SMI receive more opioid prescriptions than other veterans. Additionally, high numbers of opioid prescriptions is associated with greater use of anxiolytics/sedative-hypnotics, drug dependence and COPD-all of which pose an increased risk of respiratory depression and falls and warrant substantial caution and improved coordination between mental health and non-mental health prescribers to evaluate risk-benefit tradeoffs.

Unrecognized clozapine-related constipation leading to fatal intra-abdominal sepsis - a case report

Clozapine is the preferred antipsychotic used for the treatment of resistant schizophrenia with suicidal ideation. The drug is started at a low dose and gradually increased to a target dose of 300–450 mg/day. It is well known to cause agranulocytosis and neutropenia. Several cases of fatal sepsis have been reported in neutropenic patients and emphasis is placed on monitoring for agranulocytosis; however, clozapine also causes intestinal hypomotility and constipation, which if unrecognized can lead to intestinal obstruction, bowel necrosis, and intra-abdominal sepsis. Reduced behavioral pain reactivity in schizophrenics may alter the ability to express pain, potentially leading to a delay in the presentation for medical attention. We report a case of fatal intra-abdominal sepsis secondary to an unrecognized case of clozapine-related constipation.

A cross-sectional survey to investigate the prevalence of pain in Japanese patients with major depressive disorder and schizophrenia

We conducted a cross-sectional survey to assess the prevalence of physical pain in Japanese major depressive disorder (MDD) and schizophrenia (SZ) patients as well as in healthy controls (HCs). We also examined the association between their psychopathology and characteristics of pain according to a face-to-face survey by an experienced psychiatrist and psychologist. We analyzed 233 HCs, 94 MDD patients, and 75 SZ patients using the McGill Pain Questionnaire (MPQ) and SF-8 (all participants), the Hamilton Depression Rating Scale 21 items (MDD patients), and the Positive and Negative Symptom Scale (SZ patients). Although MDD patients experienced more pain than HCs, there was no difference in the prevalence of pain between SZ patients and HCs. Moreover, HCs with pain did not have higher SF-8 total scores than those without pain, whereas both MDD and SZ patients with pain had higher SF-8 total scores than those without pain. The severity of psychopathology in MDD and SZ patients was also positively associated with both the prevalence of pain and MPQ scores. MPQ scores were also associated with positive symptoms in SZ patients. Considering these results, physicians need to query MDD patients about physical pain during examination if they are to ensure a favorable and quick response to treatment. The severity of positive symptoms (i.e., clinical status) in SZ patients might also be associated with pain sensitivity, and warrants further investigation.

Unrecognised myocardial infarction in patients with schizophrenia

OBJECTIVE

Schizophrenia is associated with a reduction of the lifespan by 20 years, with type II diabetes and cardiovascular disease contributing the most to the increased mortality. Unrecognised or silent myocardial infarction (MI) occurs in ~30% of the population, but the rates of unrecognised MI in patients with schizophrenia have only been sparsely investigated.

METHOD

Electrocardiograms (ECG) from three psychiatric hospitals in Denmark were manually interpreted for signs of previous MI. Subsequently, ECGs were linked to the National Patient Registry in order to determine whether patients had a diagnosis consistent with previous MI.

RESULTS

A total of 937 ECGs were interpreted, 538 men (57.4%) and 399 women (42.6%). Mean age at the time of ECG acquisition was 40.6 years (95% CI: 39.7-41.5, range: 15.9-94.6). We identified 32 patients with positive ECG signs of MIs. Only two of these patients had a diagnosis of MI in the National Patient Registry. An additional number of eight patients had a diagnosis of MI in the Danish National Patient Registry, but with no ECG signs of previous MI. This means that 30 out of 40 (75%) MIs were unrecognised. Only increasing age was associated with unrecognised MI in a stepwise multiple logistic regression model compared with patients with no history of MI, OR: 1.03 per year of age, 95% CI: 1.00-1.06, p=0.021.

CONCLUSION

Unrecognised MI is common among patients with schizophrenia and may contribute to the increased mortality found in this patient group.

The prevalence and moderators of clinical pain in people with schizophrenia: a systematic review and large scale meta-analysis

BACKGROUND

People with schizophrenia frequently have physical comorbidities that can cause pain. Experimental studies report reduced pain sensitivity among schizophrenia patients, but it remains unclear if clinically relevant pain is less prevalent in schizophrenia.

METHOD

We systematically searched major electronic databases from inception till 03/2014. Articles were included that reported the prevalence of clinical pain in people with schizophrenia. Two independent authors conducted searches, completed methodological quality assessment and extracted data. A random effects relative risks (RR) meta-analysis was conducted to determine the prevalence of all-cause and specific pain in schizophrenia, and the relative prevalence compared to the general population, and to assess moderators.

RESULTS

Altogether, 14 studies were included encompassing 242,703 individuals with schizophrenia (30.2-55.8 years) and 4,259,221 controls. Different types of pain were considered. The overall pooled prevalence of clinical pain in people with schizophrenia was 34.7% (95% CI=23.6-46.6). In the comparative analysis involving 7 studies with controls, the RR was 0.99 (95% CI=0.83-1.19). The pooled prevalence of headache among 94,043 individuals with schizophrenia was 29.9% (95% CI=3-69%) and the RR compared to 4,248,284 controls was 1.32 (95% CI=0.85-2.07). In moderator analyses, neither age, sex, study quality or pain assessment method influenced pain prevalence.

CONCLUSION

Clinical pain affects a third of people with schizophrenia and levels are similar with age- and sex-comparable controls. Future research is needed to determine if similar clinical pain prevalences in schizophrenia occur despite having more painful conditions, resulting from under-reporting, higher pain thresholds or lower help seeking behaviours.

Effects of neonatal treatment with the TRPV1 agonist, capsaicin, on adult rat brain and behaviour

Treatment of neonatal rats with the transient receptor potential vanilloid 1 (TRPV1) channel agonist, capsaicin, produces life-long loss of sensory neurons expressing TRPV1 channels. Previously it was shown that rats treated on day 2 of life with capsaicin had behavioural hyperactivity in a novel environment at 5-7 weeks of age and brain changes reminiscent of those found in subjects with schizophrenia. The objective of the present study was to investigate brain and behavioural responses of adult rats treated as neonates with capsaicin. It was found that the brain changes found at 5-7 weeks in rats treated as neonates with capsaicin persisted into adulthood (12 weeks) but were less in older rats (16-18 weeks). Increased prepulse inhibition (PPI) of acoustic startle was found in these rats at 8 and 12 weeks of age rather than the deficit commonly found in animal models of schizophrenia. Subjects with schizophrenia also have reduced flare responses to niacin and methylnicotinate proposed to be mediated by prostaglandin D2 (PGD2). Flare responses are accompanied by cutaneous plasma extravasation. It was found that the cutaneous plasma extravasation responses to methylnicotinate and PGD2 were reduced in capsaicin-treated rats. In conclusion, several neuroanatomical changes observed in capsaicin-treated rats, as well as the reduced cutaneous plasma extravasation responses, indicate that the role of TRPV1 channels in schizophrenia is worthy of investigation.

[Antipsychotics-induced acute necrotizing enterocolitis: a case report]

The acute necrotizing enterocolitis (ANE) is a partial or total necrosis of the small and large intestine. This is a case report of an antipsychotic induced ANE.

Dopamine precursor depletion influences pain affect rather than pain sensation

Pain is a multidimensional experience, which includes sensory, cognitive, and affective aspects. Converging lines of evidence indicate that dopaminergic neurotransmission plays an important role in human pain perception. However, the precise effects of dopamine on different aspects of pain perception remain to be elucidated. To address this question, we experimentally decreased dopaminergic neurotransmission in 22 healthy human subjects using Acute Phenylalanine and Tyrosine Depletion (APTD). During APTD and a control condition we applied brief painful laser stimuli to the hand, assessed different aspects of pain perception, and recorded electroencephalographic responses. APTD-induced decreases of cerebral dopaminergic activity did not influence sensory aspects of pain perception. In contrast, APTD yielded increases of pain unpleasantness. The increases of unpleasantness ratings positively correlated with effectiveness of APTD. Our finding of an influence of dopaminergic neurotransmission on affective but not sensory aspects of phasic pain suggests that analgesic effects of dopamine might be mediated by indirect effects on pain affect rather than by direct effects on ascending nociceptive signals. These findings contribute to our understanding of the complex relationship between dopamine and pain perception, which may play a role in various clinical pain states.

Temporomandibular disorders in patients with schizophrenia using antipsychotic agents: a discussion paper

Patients with psychiatric problems show a tendency to develop temporomandibular disorders (TMD). Particularly, patients with schizophrenia are quite likely to have signs and symptoms of TMD due to the impairment of their oral health, the use of antipsychotic drugs, and other general health problems. In nonschizophrenic populations, TMD have been considered as the main cause of nondental pain in the orofacial region, involving mechanisms associated with changes in masticatory activity at the cortical and neuromuscular levels. Individuals with schizophrenia do not usually complain of pain, and TMD is misdiagnosed in this population. In this paper, we aimed to review the clinical aspects of TMD in people with schizophrenia on antipsychotic drug therapy.

Physical comorbidity and its relevance on mortality in schizophrenia: a naturalistic 12-year follow-up in general hospital admissions

Schizophrenia is a major psychotic disorder with significant comorbidity and mortality. Patients with schizophrenia are said to suffer more type-2 diabetes mellitus (T2DM) and diabetogenic complications. However, there is little consistent evidence that comorbidity with physical diseases leads to excess mortality in schizophrenic patients. Consequently, we investigated whether the burden of physical comorbidity and its relevance on hospital mortality differed between patients with and without schizophrenia in a 12-year follow-up in general hospital admissions. During 1 January 2000 and 31 June 2012, 1418 adult patients with schizophrenia were admitted to three General Manchester NHS Hospitals. All comorbid diseases with a prevalemce ≥1% were compared with those of 14,180 age- and gender-matched hospital controls. Risk factors, i.e. comorbid diseases that were predictors for general hospital mortality were identified using multivariate logistic regression analyses. Compared with controls, schizophrenic patients had a higher proportion of emergency admissions (69.8 vs. 43.0%), an extended average length of stay at index hospitalization (8.1 vs. 3.4 days), a higher number of hospital admissions (11.5 vs. 6.3), a shorter length of survival (1895 vs. 2161 days), and a nearly twofold increased mortality rate (18.0 vs. 9.7%). Schizophrenic patients suffered more depression, T2DM, alcohol abuse, asthma, COPD, and twenty-three more diseases, many of them diabetic-related complications or other environmentally influenced conditions. In contrast, hypertension, cataract, angina, and hyperlipidaemia were less prevalent in the schizophrenia population compared to the control population. In deceased schizophrenic patients, T2DM was the most frequently recorded comorbidity, contributing to 31.4% of hospital deaths (only 14.4% of schizophrenic patients with comorbid T2DM survived the study period). Further predictors of general hospital mortality in schizophrenia were found to be alcoholic liver disease (OR = 10.3), parkinsonism (OR = 5.0), T1DM (OR = 3.8), non-specific renal failure (OR = 3.5), ischaemic stroke (OR = 3.3), pneumonia (OR = 3.0), iron-deficiency anaemia (OR = 2.8), COPD (OR = 2.8), and bronchitis (OR = 2.6). There were no significant differences in their impact on hospital mortality compared to control subjects with the same diseases except parkinsonism which was associated with higher mortality in the schizophrenia population compared with the control population. The prevalence of parkinsonism was significantly elevated in the 255 deceased schizophrenic patients (5.5 %) than in those 1,163 surviving the study period (0.8 %, OR = 5.0) and deceased schizophrenic patients had significantly more suffered extrapyramidal symptoms than deceased control subjects (5.5 vs. 1.5 %). Therefore patients with schizophrenia have a higher burden of physical comorbidity that is associated with a worse outcome in a 12-year follow-up of mortality in general hospitals compared with hospital controls. However, schizophrenic patients die of the same physical diseases as their peers without schizophrenia. The most relevant physical risk factors of general hospital mortality are T2DM, COPD and infectious respiratory complications, iron-deficiency anaemia, T1DM, unspecific renal failure, ischaemic stroke, and alcoholic liver disease. Additionally, parkinsonism is a major risk factor for general hospital mortality in schizophrenia. Thus, optimal monitoring and management of acute T2DM and COPD with its infectious respiratory complications, as well as the accurate detection and management of iron-deficiency anaemia, of diabetic-related long-term micro- and macrovascular complications, of alcoholic liver disease, and of extrapyramidal symptoms are of utmost relevance in schizophrenia.

Social alienation in schizophrenia patients: association with insula responsiveness to facial expressions of disgust

INTRODUCTION

Among the functional neuroimaging studies on emotional face processing in schizophrenia, few have used paradigms with facial expressions of disgust. In this study, we investigated whether schizophrenia patients show less insula activation to macro-expressions (overt, clearly visible expressions) and micro-expressions (covert, very brief expressions) of disgust than healthy controls. Furthermore, departing from the assumption that disgust faces signal social rejection, we examined whether perceptual sensitivity to disgust is related to social alienation in patients and controls. We hypothesized that high insula responsiveness to facial disgust predicts social alienation.

METHODS

We used functional magnetic resonance imaging to measure insula activation in 36 schizophrenia patients and 40 healthy controls. During scanning, subjects passively viewed covert and overt presentations of disgust and neutral faces. To measure social alienation, a social loneliness scale and an agreeableness scale were administered.

RESULTS

Schizophrenia patients exhibited reduced insula activation in response to covert facial expressions of disgust. With respect to macro-expressions of disgust, no between-group differences emerged. In patients, insula responsiveness to covert faces of disgust was positively correlated with social loneliness. Furthermore, patients' insula responsiveness to covert and overt faces of disgust was negatively correlated with agreeableness. In controls, insula responsiveness to covert expressions of disgust correlated negatively with agreeableness.

DISCUSSION

Schizophrenia patients show reduced insula responsiveness to micro-expressions but not macro-expressions of disgust compared to healthy controls. In patients, low agreeableness was associated with stronger insula response to micro- and macro-expressions of disgust. Patients with a strong tendency to feel uncomfortable with social interactions appear to be characterized by a high sensitivity for facial expression signaling social rejection. Given the associations of insula responsiveness to covert disgust expression with low agreeableness in healthy individuals, insula responsiveness to expressions of disgust might be in general a neural marker of the personality trait of agreeableness.

Schizophrenia as a self-disorder due to perceptual incoherence

The aim of this review is to describe the potential relationship between multisensory disintegration and self-disorders in schizophrenia spectrum disorders. Sensory processing impairments affecting multisensory integration have been demonstrated in schizophrenia. From a developmental perspective multisensory integration is considered to be crucial for normal self-experience. An impairment of multisensory integration is called 'perceptual incoherence'. We theorize that perceptual incoherence may evoke incoherent self-experiences including depersonalization, ambivalence, diminished sense of agency, and 'loosening of associations' between thoughts, feelings and actions that lie within the framework of 'self-disorders' as described by Sass and Parnas (2003). We postulate that subconscious attempts to restore perceptual coherence may induce hallucinations and delusions. Increased insight into mechanisms underlying 'self-disorders' may enhance our understanding of schizophrenia, improve recognition of early psychosis, and extend the range of therapeutic possibilities.

Isolation rearing reduces mechanical allodynia in a mouse model of chronic inflammatory pain

Social isolation rearing in mice after weaning reduces pain sensitivity to acute pain, and this hypoalgesia is mediated by the descending serotonergic pain inhibitory system in which the spinal serotonin (5-HT)1A receptor is involved. However, it is not known whether isolation rearing affects pain sensitivity to neuropathic or inflammatory chronic pain. In this study, we examined the effects of isolation rearing on chronic pain induced by Freund's complete adjuvant (FCA) and partial sciatic nerve ligation using the von Frey test (to assess mechanical allodynia) and the plantar test (to assess thermal hyperalgesia). In the FCA model, isolation rearing reduced mechanical allodynia, but not thermal hyperalgesia. In contrast, isolation rearing had no effect on allodynia or hyperalgesia in the sciatic nerve ligation model. The isolation rearing-induced inhibition of allodynia was alleviated by intrathecal injection of WAY100635, a selective 5-HT1A receptor antagonist. FCA increased 5-HT turnover and decreased 5-HT1A receptor expression in the spinal cord of group-reared mice, while it did not have these effects in isolation-reared mice. These results suggest that FCA suppresses the serotonergic pain inhibitory system selectively in group-reared mice. Moreover, systemic administration of osemozotan, a selective 5-HT1A receptor agonist, inhibited FCA-induced mechanical allodynia in group-reared mice, and this effect of the drug was suppressed by intrathecal injection of WAY100635. Collectively, these findings suggest that isolation rearing selectively reduces FCA-induced mechanical allodynia in mice and that this effect is mediated by the activation of spinal 5-HT1A receptors.

Reintroduction of Clozapine After Perforation of the Large Intestine—A Case Report and Review of the Literature

OBJECTIVE

To report on a patient who was successfully rechallenged with clozapine after perforation of the large intestine and pulmonary embolism postoperatively, and provide a literature review on clozapine rechallenge.

CASE SUMMARY

A 46-year-old Japanese man with treatment-resistant schizophrenia developed constipation and slight abdominal discomfort while taking clozapine 275 mg/day. He developed appendicitis, leading to perforation of the large intestine. During the postsurgery period, a partial embolism of the pulmonary artery was revealed. The patient's constipation was relieved when clozapine was discontinued, but other antipsychotics failed to control his delusions well. After thorough discussion, it was decided to rechallenge with clozapine. The low dose of clozapine 200 mg/day was tolerable for his delusion, and his constipation was managed with laxatives and exercises until 8 months after the accident.

DISCUSSION

Clozapine is a gold standard medication in treatment-resistant schizophrenia but is associated with various adverse effects, some of which are life-threatening. Reintroduction of clozapine after severe adverse drug effects when other medications are not effective almost always poses a clinical dilemma for mental health professionals. A PubMed search (to January 25, 2013) using the key words clozapine and rechallenge found 50 articles. There were only sporadic positive case reports regarding the rechallenge after clozapine-related serious gastrointestinal problems.

CONCLUSIONS

From the currently available evidence, most psychiatrists appear to avoid reintroduction of clozapine. However, the evidence is too weak to draw a definitive conclusion about reintroduction of this drug. Reintroduction of clozapine after initial adverse effects in patients with treatment-resistant schizophrenia may warrant case-by-case judgment, but needs to be further investigated.

Involvement of spinal 5-HT1A receptors in isolation rearing-induced hypoalgesia in mice

RATIONALE

Isolation rearing in rodents causes not only abnormal behaviors which resemble the clinical symptoms of schizophrenia but also hypoalgesia in thermal nociception models. However, the mechanism of the hypoalgesia is not known.

OBJECTIVES

The present study investigated the effect of isolation rearing on acute pain and the descending pain inhibitory pathways in mice.

RESULTS

Rearing in isolation for 6 weeks from post-weaning reduced pain sensitivity in the hot plate test and acetic acid-induced writhing test. Isolation rearing also reduced the intraplantar capsaicin-induced licking behavior. Capsaicin increased c-Fos expression, a neuronal activity marker, in the spinal cord and primary somatosensory cortex both in group- and isolation-reared mice, but this effect did not differ between groups. On the other hand, c-Fos expression in the anterior cingulate cortex, periaqueductal gray matter, and rostral ventromedial medulla, but not in the spinal cord or somatosensory cortex, was enhanced by isolation rearing. Systemic administration of WAY100635 (serotonin (5-HT)1A receptor antagonist), but not of ketanserin (5-HT2 receptor antagonist), prazosin (α1-adrenoceptor antagonist), or yohimbine (α2-adrenoceptor antagonist), attenuated isolation rearing-induced hypoalgesia in capsaicin-induced licking behavior. Attenuation of isolation rearing-induced hypoalgesia was also observed following the intrathecal injection of WAY100635. Naloxone, an opioid receptor antagonist, did not affect the hypoalgesia in isolation-reared mice.

CONCLUSIONS

These findings suggest that isolation rearing causes hypoalgesia in mouse models of acute pain and imply that the spinal 5-HT1A receptor activation probably through descending serotonergic inhibitory pathway is involved in isolation rearing-induced hypoalgesia.

Pain and analgesia: the value of salience circuits

Evaluating external and internal stimuli is critical to survival. Potentially tissue-damaging conditions generate sensory experiences that the organism must respond to in an appropriate, adaptive manner (e.g., withdrawal from the noxious stimulus, if possible, or seeking relief from pain and discomfort). The importance we assign to a signal generated by a noxious state, its salience, reflects our belief as to how likely the underlying situation is to impact our chance of survival. Importantly, it has been hypothesized that aberrant functioning of the brain circuits which assign salience values to stimuli may contribute to chronic pain. We describe examples of this phenomenon, including 'feeling pain' in the absence of a painful stimulus, reporting minimal pain in the setting of major trauma, having an 'analgesic' response in the absence of an active treatment, or reporting no pain relief after administration of a potent analgesic medication, which may provide critical insights into the role that salience circuits play in contributing to numerous conditions characterized by persistent pain. Collectively, a refined understanding of abnormal activity or connectivity of elements within the salience network may allow us to more effectively target interventions to relevant components of this network in patients with chronic pain.