Giulia Lisi

Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration

Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity.

Novel psychoactive substance consumption is more represented in bipolar disorder than in psychotic disorders: A multicenter-observational study

Comorbidities between psychiatric diseases and use of traditional substances of abuse are common. Nevertheless, there are few data regarding the use of novel psychoactive substances (NPS) among psychiatric patients. Aim of this multicentre survey is to investigate the consumption of a number of psychoactive substances in a young psychiatric sample.

A critical review and meta-analysis of the perceptual pseudoneglect across psychiatric disorders: Is there a continuum?

The phenomenon known as “perceptual pseudoneglect” refers to the leftward bias in visuospatial attention in non-clinical samples, possibly as a consequence of right hemisphere dominance for visuospatial attention. The degree of such a lateralized visuospatial attention bias is often assessed using the line bisection task. Interestingly, various psychiatric disorders may influence the expression of this phenomenon. The aim of this paper was to perform a critical appraisal of the literature on the expression of the perceptual pseudoneglect across all psychiatric disorders accompanied by meta-analytical evaluation of the data. Moreover, we will discuss whether this phenomenon may be considered as a trait marker across different psychiatric disorders.

Negative correlation between leftward bias in line bisection and schizotypal features in healthy subjects

Introduction: Recent studies have found a lack of normal pseudoneglect in schizophrenia patients and in their first degree relatives. Similarly, several contributions have reported that measures of schizotypy in the healthy population may be related to signs of right-sided lateralization, but most of these studies differ greatly in methodology (sample size, choice of schizotypy scales, and laterality tasks) and, consequently, the results cannot be compared and so definitive conclusion cannot be drawn. In this study, our purpose is to investigate whether some tasks of spatial attention may be related to different dimensions of schizotypy not only in a larger sample of healthy subjects (HS), but testing the same people with several supposedly related measures several times. Materials and Methods: In the first part of the study (Part I), the performance on “paper and pencil” line bisection (LB) tasks in 205 HS was investigated. Each task was repeated three times. In the second part of the study (Part II), a subgroup of 80 subjects performed a computerized version of the LB test and of the mental number line bisection (MNL) test. In both parts of the study, every subject completed the 74-item version of the Schizotypal Personality Questionnaire (SPQ) and the Edinburgh Handedness Inventory (EHI). Results: In both parts of the study, high scores on the subscale “magical thinking” of SPQ have resulted in being closely linked to a decreased pseudoneglect as assessed by the LB task. On the contrary, right handedness is related to an increased leftward bias at the same task. No association was found between MNL and the other variables. Discussion: The main finding of this study is that a decreased spatial leftward bias at the LB task correlates with positive schizotypy in the healthy population. This finding supports the hypothesis that a deviation from leftward hemispatial visual preference may be related to the degree of psychosis-like schizotypal signs in non-clinical population and should be investigated as a possible marker of psychosis.

Trauma-Related Disorders: Sexual Abuse and Psychiatric Comorbidities

Trauma occurs when a subject happens to be exposed to death, threatened death, actual or threatened serious injury, or actual or threatened sexual violence; historical studies raised much interest on the persistent role of past traumatic experiences on people’s current lives. Confrontation with trauma results in the release of important neurochemical factors, capable of compromising subjective integrative capacity and the ordinary process of neurodevelopment. DSM-5 classifies trauma- and stressor-related disorders in a specific chapter that includes the reactive attachment disorder, the disinhibited social engagement disorder, acute stress disorder, the adjustment disorders, and post-traumatic stress disorder.

Sexual Dysfunctions and Mood and Anxiety Disorders

Sexual dysfunctions are frequently associated with depression and anxiety: they are reported to be two to three times more likely in depressed population then in non-depressed population, and according to literature, the existence of a bidirectional relationship between depressive symptoms, anxiety, and sexual dysfunctions should always be taken into account. The same etiological mechanisms that are responsible for mood disorders can also be at the base of sexual dysfunctions: patients with sexual dysfunctions can, in fact, more commonly develop lower sexual satisfaction and control, higher distress, and higher social anxiety. What is more, in patients with a diagnosis of bipolar disorder, a disruption in sexual functioning can often be associated with both depressive and manic episodes, and severe fluctuations in sexual life may be difficult to manage for both the patients and their partners. To make the picture even more complex, pharmacological treatments used routinely may cause alterations in desire, excitement, and orgasm. In order to define the best possible treatment for the patient, every careful clinician should routinely evaluate symptoms of mood and anxiety disorders in individuals presenting with sexual complaints.

Asymmetries in initiation of aiming movements in schizophrenia

&NA; Several studies have reported motor symptoms in schizophrenia (SCZ), in some cases describing asymmetries in their manifestation. To date, biases were mainly reported for sequential movements, and the hypothesis was raised of a dopamine‐related hemispheric imbalance. Aim of this research is to better characterize asymmetries in movement initiation in SCZ by exploring single actions. Fourteen SCZ patients and fourteen healthy subjects were recruited. On a trial‐by‐trial basis, participants were instructed to reach for one of eight possible targets. Measures of movement initiation and execution were collected. Starting point, target and moving limb were systematically varied to check for asymmetric responses. Results showed that SCZ patients, besides being overall slower than controls, additionally presented with a bias affecting both the moving hand and the side from which movements were initiated. This finding is discussed in relation to hemispheric lateralization in motor control. HighlightsSchizophrenic patients show spatial asymmetries in motor preparation.The interval prior to movement is longer for actions starting in the right space.In addition, a delay in motor preparation is found for the right hand.This pattern suggests a dysfunction in hemispheric asymmetries.Lateralized functional anomalies in the nigro‐striatal system are hypothesized.

Left hemispheric breakdown of LTP-like cortico-cortical plasticity in schizophrenic patients

OBJECTIVE Altered cortical connectivity and plasticity seems to be asymmetrical between the hemispheres in patients with schizophrenia (SCZ). We evaluated long-term potentiation (LTP) in parietal-frontal circuits of both hemispheres using a cortico-cortical Paired Associative Stimulation (cc-PAS) protocol testing the rules of Hebbian-like spike timing dependent plasticity (SPTD). METHODS 12 SCZ and 12 healthy subjects (HS) underwent a cc-PAS protocol to activate, by means of paired pulses of transcranial magnetic stimulation (TMS), the short-latency connection between posterior parietal cortex (PPC) and primary motor cortex (M1) of both hemispheres. Motor-evoked potentials (MEPs) were collected to assess the time course of the after effects of cc-PAS protocol measuring MEP amplitude as index of cortico-cortical associative plasticity. RESULTS While HS showed a similar time course of LTP-like plasticity in the two hemispheres, SCZ revealed a weaker late-LTP-like plasticity in the left compared to the right hemisphere after cc-PAS protocol. CONCLUSIONS SCZ failed to show the typical long-lasting increase of M1 excitability observed after cc-PAS protocol in both hemispheres, with a greater reduction in the left one. SIGNIFICANCE Our findings provide novel neurophysiological evidence for an asymmetric impairment of the left parietal-frontal network in SCZ patients.

Non Invasive Brain Stimulation to Improve Metaphoric Speech Processing in Schizophrenia: A Pilot Study

Background: An underestimated feature of schizophrenia is the impaired processing of the metaphoric speech, mainly due to a reduced activation of the right hemisphere. Objective/hypothesis: We investigated whether anodal tDCS over the right posterior superior temporal sulcus may improve the processing of metaphoric speech of schizophrenia patients (SCZ). Methods: Ten SCZ subjects were randomly allocated to receive a single session of active tDCS or sham stimulation. Metaphoric speech processing was investigated through a discrimination task between literal or metaphoric expressions. Results: tDCS improved significantly the reaction time but not the accuracy of the answers at the discrimination task compared to sham stimulation. Conclusion: These preliminary results should be verified in larger studies with more sessions of tDCS.