Psychiatric disorders associated with 22q11.2 deletion syndrome

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Towards a loop representation for quantum canonical supergravity

We study several aspects of the canonical quantization of supergravity in terms of the Asthekar variables. We cast the theory in terms of a GSU(2) connection and we introduce a loop representation. The solution space is remarkably similar to the loop representation of ordinary gravity, the main difference being the form of the Mandelstam identities. Physical states are in general given by knot invariants that are compatible with the GSU(2) Mandelstam identities. There is an explicit solution to all the quantum constraint equations connected with the Chern-Simons form, which leads to a new knot invariant polynomial in the loop representation

Visual perception and dissociation during Mirror Gazing Test in patients with anorexia nervosa : a preliminary study

Purpose: It has been widely shown that dissociative features might play a fundamental role in producing body image distortions in patients affected by eating disorders. Here, we hypothesize that the Mirror Gazing Test (MGT), a task consisting in mirror exposure in a condition of sensory deprivation, would elicit dissociative symptoms in a group of patients with anorexia nervosa (AN). Methods: Fourteen patients with AN and fourteen healthy controls (HC) underwent a 10 min MGT and completed the Strange Face Questionnaire and a short version of the Clinician-Administered Dissociative States Scale, along with a psychological assessment for eating disorders psychopathology, anxiety and depression. Results: AN patients reported a higher number of strange-face apparitions and dissociative sensations than HC during the MGT. Dissociative identity (compartmentalization of two or more identities) and depersonalization (detachment of bodily-self) were much higher in patients with AN than in HC. These findings were correlated with body dissatisfaction and disruption in interoceptive awareness. Conclusion: Dissociation and body image dysfunction are strongly connected in the pathophysiology of anorexia nervosa. Future research should investigate the same aspects in other psychiatric conditions characterized by body image distortions, such as Body Dysmorphic Disorder. Level of evidence: I, Experimental studies

Dependency-like behaviors and pain coping styles in subjects with chronic migraine and medication overuse : Results from a 1-year follow-up study

Background: Even after successful detoxification, 20-40% of subjects presenting chronic migraine with symptomatic medication overuse (CMwMO) relapse into medication overuse within one year. In this restrospective analysis on subjects referred to our center for detoxification, we investigated whether personality traits, dependency-like behaviors and pain coping styles predicted those who relapsed into medication overuse within the 12\ua0months following the detoxification and those who did not.Methods: 63 patients with CMwMO were assessed for personality traits, mood and anxiety, pain coping styles and dependency-like behaviors prior-to and one year after a detoxification program.Results: Of the 42 subjects who attended 1-year follow-up interviews, 11 relapsed into medication overuse despite a temporary benefit from detoxification and did not show clinical or psychological improvement, instead reporting increased anxiety and unmodified perpetuation of severe dependency-like behaviors. In contrast, subjects who did not relapse into medication overuse had clinical improvements that generalized to untreated domains, including decreased depressive symptoms and dependency-like behaviors, although showing unmodified low internal control over pain.Conclusions: Subjects who did not fall into medication overuse throughout the 12\ua0months following the detoxification showed improved clinical, affective and dependence-related outcomes, but not pain coping strategies. Conversely, subjects who relapsed within one year into CMwMO continued to experience significant disability, pain intensity, and dependency-like behaviors. We believe that the persistence of maladaptive pain coping strategies and residual symptomatology increase the risk for recurrent relapses, against which pharmacological interventions are only partially effective. Further studies investigating predictors of relapse are needed to inform multi-disciplinary interventions for CMwMO

Iatrogenic hypothyroidism and acute psychosis

We present the case of a 39 years old woman who was referred to our day hospital unit because of anxiety. The patient didn\u2019t endorse any past psychiatric symptoms except for an acute psychotic episode in August 2010. In June 2010 she was diagnosed with hypothyroidism (likely due to Hashimoto\u2019s thyroiditis) and was started on Methilmazole 30 mg. Shortly after that she reported persecutory ideation and hallucinations which quickly progressed, until she was hospitalized in a psychiatric facility. Upon admittance her lab work revealed severe hypothyroidism. Methilmazole was suspended, she was started on Haloperidol, and the symptoms went into remission after four days. Despite the fact that she self discontinued Haloperidol shortly after discharge, she showed no sign of psychotic symptoms. While it is widely accepted that hypothyroidism can cause depressive symptoms, to the best of our knowledge very few cases of psychotic symptoms associated with this condition have been described. Based on the patient\u2019s clinical history, on the rapid onset and remission of symptoms, on the lab values and on the doses of medication that were prescribed, we hypothesize that our patient\u2019s psychotic episode was caused by iatrogenic hypothyroidism

The anticipation, perception of affective touch in women with, recovered from Anorexia Nervosa

Disruptions in reward processing and anhedonia have long been observed in Anorexia Nervosa (AN). Interoceptive deficits have also been observed in AN, including reduced tactile pleasure. However, the extent to which this tactile anhedonia is specifically liked to an impairment in a specialized, interoceptive C-tactile system originating at the periphery, or a more top-down mechanism in the processing of tactile pleasantness remains debated. Here, we investigated differences between patients with and recovered from AN and healthy controls in the perception of pleasantness of touch delivered in a CT-optimal versus a CT-non-optimal manner, and in their top-down, anticipatory beliefs about the perceived pleasantness of touch. To this end, we measured the anticipated pleasantness of various materials touching the skin and the perceived pleasantness of light, dynamic touch applied to theforearmof 27 women with AN, 24 women who have recovered and 30 healthy controls using C Tactile (CT) afferents-optimal (slow) and non-optimal (fast) velocities. Our results showed that both clinical groups anticipated tactile experiences and rated delivered tactile stimuli as less pleasant than healthy controls, but the latter difference was not related to the CT optimality of the stimulation. Instead, differences in the perception of CT-optimal touch were predicted by differences in top-down beliefs, alexithymia and interoceptive sensibility. Thus, tactile anhedonia in AN might persist as a trait even after otherwise successful recovery of AN and it is not linked to a bottom-up interoceptive deficit in the CT system, but rather to a learned, defective top-down anticipation of tactile pleasantness

Generally covariant model of a scalar field with high frequency dispersion and the cosmological horizon problem

Short distance structure of spacetime may show up in the form of high freqency dispersion. Although such dispersion is not locally Lorentz invariant, we show in a scalar field model how it can nevertheless be incorporated into a generally covariant metric theory of gravity provided the locally preferred frame is dynamical. We evaluate the resulting energy-momentum tensor and compute its expectation value for a quantum field in a thermal state. The equation of state differs at high temperatures from the usual one, but not by enough to impact the problems of a hot big bang cosmology. We show that a superluminal dispersion relation can solve the horizon problem via superluminal equilibration, however it cannot do so while remaining outside the Planck regime unless the dispersion relation is artificially chosen to have a rather steep dependence on wavevector.Comment: 4 pages, 1 figure; New section added with discussion of solution to the cosmological horizon problem using superluminal dispersion, title changed to reflect new content, various additional minor change

The graviton vacuum as a distributional state in kinematic Loop Quantum Gravity

The quantum behaviour of weak gravitational fields admits an adequate, albeit approximate, description by those graviton states in which the expectation values and fluctuations of the linearised gravitational field are small. Such states must approximate corresponding states in full quantum gravity. We analyse the nature of this approximation for the graviton vacuum state in the context of kinematical Loop Quantum Gravity (LQG) wherein the constraints are ignored. We identify the graviton vacuum state with kinematically non-normalizable, distributional states in LQG by demanding that relations between linearised operator actions on the former are mirrored by those of their non-linear counterparts on the latter. We define a semi- norm on the space of kinematical distributions and show that the identification is approximate upto distributions which are small in this semi-norm. We argue that our candidate states are annihilated by the linearised constraints (expressed as operators in the full theory) to leading order in the parameter characterising the approximation. This suggests the possibility, in a scheme such as ours, of solving the full constraints order by order in this parameter. The main drawback of our considerations is that they depend on certain auxilliary constructions which, though mathematically well defined, do not arise from physical insight. Our work is an attempt to implement an earlier proposal of Iwasaki and Rovelli.Comment: 44 pages, no figure