Hemispheric asymmetry and psychopathological dimensions in drug-free patients with schizophrenia

Negative symptoms of schizophrenia: Trying to answer unanswered research questions

My research has focused on unmet needs in caring for people with schizophrenia. In particular, I focused on negative symptoms, a complex psychopathological dimension of the disorder, with a significant impact on the disease outcome, and not effectively addressed by existing treatments. In the present commentary, I summarize the trajectory of my research activity. I start with the description of my initial attempts to define the role of the dorsolateral prefrontal cortex in the pathogenesis of broadly defined negative symptoms. Then, I report on the evidence that led me to realize that no progress in research on schizophrenia negative symptoms could occur without considering the heterogeneity and complexity of the construct. Finally, I illustrate my attempts to succeed in this direction and the most pressing unsolved issues in this research field.

Characterization of premorbid functioning during childhood in patients with deficit vs. non-deficit schizophrenia and in their healthy siblings

Impaired premorbid adjustment has been reported in patients with schizophrenia, generally in association with unfavorable aspects of the illness (e.g., poor outcome and severe negative symptoms). Several studies attempted to define the domains of premorbid dysfunction associated with negative symptoms and poor outcome; however, most of them assessed broadly defined negative symptoms. The present study was aimed to characterize premorbid functioning in a group of patients with deficit schizophrenia (DS), characterized by the presence of at least two primary and persistent negative symptoms (PPNS), and one of patients with a diagnosis of schizophrenia who did not meet criteria for DS (NDS). The presence of emotional/behavioral problems during childhood was investigated using the Childhood Behavior Checklist (CBCL) in both patient groups and in their respective healthy siblings. The Premorbid Adjustment Scale (PAS) was also used to assess premorbid functioning during childhood in the two patient groups. PPNS were also treated as a continuous variable and correlated with the indices of premorbid functioning regardless the DS/NDS categorization. DS patients, as compared to NDS, showed higher scores on the CBCL subscale "Withdrawn". Both DS and NDS patients showed, as compared to their healthy siblings, a greater impairment on almost all CBCL subscales. PAS findings revealed that DS patients had poorer premorbid adjustment than NDS. No significant correlation between premorbid functioning and PPNS was observed. These findings support the hypothesis that DS has a different developmental trajectory with respect to NDS, and that premorbid adjustment is one of the essential aspects of its characterization.

Hemispheric language asymmetry in first episode psychosis and schizotypy: the role of cannabis consumption and cognitive disorganization

Cannabis use has been related to an elevated psychosis risk and attenuated cognitive functioning. Cannabis-related cognitive impairments are also observed in populations along the psychosis dimension. We here investigated whether a potential behavioral marker of the psychosis dimension (attenuated functional hemispheric asymmetry) is even further attenuated in individuals using cannabis (CU) vs those not using cannabis (nCU). We tested 29 patients with first-episode psychosis (FEP; 11 CU) and 90 healthy controls (38 CU) on lateralized lexical decisions assessing left-hemisphere language dominance. In patients, psychotic symptoms were assessed by Positive & Negative Symptom Scale (PANSS). In controls, self-reported schizotypy was assessed (The Oxford-Liverpool Inventory of Feelings and Experiences: O-LIFE). Results indicated that nCU FEP patients had a relative reduced hemispheric asymmetry, as did controls with increasing cognitive disorganization (CogDis) scores, in particular when belonging to the group of nCU controls. Positive, disorganized and negative PANSS scores in patients and negative and positive schizotypy in controls were unrelated to hemispheric asymmetry. These findings suggest that cannabis use potentially balances rather than exacerbates uncommon hemispheric laterality patterns. Moreover, in healthy populations, the potential stabilization of typical hemispheric asymmetry in CU might be most relevant to individuals with elevated CogDis. We discuss the potential beneficial and harmful effects of cannabis use along the psychosis dimension together with propositions for future studies that should account for the mediating role of additional substances (eg nicotine), cannabis composition (eg cannabidiol content), and individual differences (eg physical health, or absence of significant polysubstance use).

A case of right cerebellopontine-angle lesion: psychotic symptoms and magnetic resonance imaging findings

Here, we report psychotic symptoms together with a right cerebellopontine-angle lesion. A37-year-old female patient presented with a trigeminal Schwannoma occupying the right cerebellopontine angle. Her psychotic symptoms included auditory hallucinations and delusions of persecution. T1- and T2-weighted images on magnetic resonance imaging (MRI) revealed hyperintense and hypointense areas in the right cerebellopontine angle, respectively. The clinical and neuroimaging reviews in this case suggest that sudden onset of psychotic symptoms at a mature age may be associated with a right cerebellopontine-angle lesion and that MRI should be used to evaluate possible organic bases in patients that present with psychosis.

Neurocognitive functioning in bulimia nervosa: the role of neuroendocrine, personality and clinical aspects

BACKGROUND

Studies investigating neurocognitive impairment in subjects with eating disorders (EDs) have reported heterogeneous patterns of impairment and, in some instances, no dysfunction. The present study aimed to define the pattern of neurocognitive impairment in a large sample of bulimia nervosa (BN) patients and to demonstrate that neuroendocrine, personality and clinical characteristics influence neurocognitive performance in BN.

METHOD

Attention/immediate memory, set shifting, perseveration, conditional and implicit learning were evaluated in 83 untreated female patients with BN and 77 healthy controls (HC). Cortisol and 17β-estradiol plasma levels were assessed. Cloninger's Temperament and Character Inventory - Revised (TCI-R), the Bulimic Investigation Test Edinburgh (BITE) and the Montgomery-Asberg Depression Rating Scale (MADRS) were administered.

RESULTS

No impairment of cognitive performance was found in subjects with BN compared with HC. Cortisol and 'Self-directedness' were associated with better performance on conditional learning whereas 17β-estradiol had a negative influence on this domain; 'Reward dependence' was associated with worse performance on implicit learning; and depressive symptomatology influenced performance on the Wisconsin Card Sorting Test (WCST) negatively.

CONCLUSIONS

No cognitive impairment was found in untreated patients with BN. Neuroendocrine, personality and clinical variables do influence neurocognitive functioning and might explain discrepancies in literature findings.

Social skills and neurocognitive individualized training in schizophrenia: comparison with structured leisure activities

Cognitive impairment and deficits in social skills have been largely documented in patients with schizophrenia and are increasingly recognized as rate-limiting factors for recovery. Evidence has been provided that cognitive training and social skills training (SST) are effective to treat cognitive and social skills impairment in schizophrenia; however, the translation of improved performance on cognitive or social skills tasks into improved functional outcome is controversial. According to recent reviews, interventions providing cognitive training in conjunction with psychosocial rehabilitation have a greater impact on functional outcome than either intervention alone suggesting that the two treatment approaches may work together in a synergistic fashion. The present pilot study was designed to test the hypothesis that an integrated rehabilitation program, including individualized cognitive and SST, is more effective than the structured leisure activities (SLA) carried out in many Italian Mental Health Departments. The primary outcome measure was subjects' personal and social functioning as assessed by the Interview for the assessment of disability. The study is based on a controlled design including randomization to treatment groups, blind assessments and stable pharmacological treatment. Subjects were recruited among patients attending three psychiatric facilities located in the Italian region Campania. Thirty patients were randomized to the experimental program "social skills and neurocognitive individualized training" (SSANIT), and 30 to SLA. The two programs were matched for the overall duration as well as frequency and duration of the sessions. The two groups of patients did not differ at baseline on psychopathology, neurocognitive and personal/social functioning. After 6 months of treatment, personal and social functioning was significantly better in patients assigned to SSANIT than in those assigned to usual rehabilitation activities practiced in Mental Health Departments. No advantage was observed for either program on psychopathological and cognitive outcome indices. As for other integrated programs, also for SSANIT further studies are needed to verify generalization and persistence of the observed gains, and to clarify most adequate length and doses of the therapeutic intervention as well as the relative contribution of each program component to its impact on subjects' disability.

Deficit schizophrenia: an overview of clinical, biological and treatment aspects

The concept of deficit schizophrenia is regarded as one of the most promising attempts to reduce heterogeneity within schizophrenia. This paper summarizes the clinical, neurocognitive, brain imaging and electrophysiological correlates of this subtype of schizophrenia. Attempts to identify genetic and non-genetic risk factors are reviewed. Methodological limitations of studies supporting the efficacy of atypical antipsychotics in the treatment of the syndrome are highlighted. Two decades of research on deficit schizophrenia have failed to prove that it represents the extreme end of a severity continuum in schizophrenia, while some findings support the claim that it may be a separate disease entity.

Patterns of structural MRI abnormalities in deficit and nondeficit schizophrenia

Negative symptoms of schizophrenia have generally been found in association with ventricular enlargement and prefrontal abnormalities. These relationships, however, have not been observed consistently, most probably because negative symptoms are heterogeneous and result from different pathophysiological mechanisms. The concept of deficit schizophrenia (DS) was introduced by Carpenter et al to identify a clinically homogeneous subgroup of patients characterized by the presence of primary and enduring negative symptoms. Findings of brain structural abnormalities reported by magnetic resonance imaging (MRI) studies focusing on DS have been mixed. The present study included 34 patients with DS, 32 with nondeficit schizophrenia (NDS), and 31 healthy comparison subjects, providing the largest set of MRI findings in DS published so far. The Schedule for the Deficit Syndrome was used to categorize patients as DS or NDS patients. The 2 patient groups were matched on age and gender and did not differ on clinical variables, except for higher scores on the negative dimension and more impaired interpersonal relationships in DS than in NDS subjects. Lateral ventricles were larger in NDS than in control subjects but were not enlarged in patients with DS. The cingulate gyri volume was smaller in NDS but not in DS patients as compared with healthy subjects. Both groups had smaller dorsolateral prefrontal cortex and temporal lobes than healthy subjects, but DS patients had significantly less right temporal lobe volume as compared with NDS patients. These findings do not support the hypothesis that DS is the extreme end of a severity continuum within schizophrenia.

Induced gamma activity and event-related coherence in schizophrenia

Evidence has been provided that high frequency oscillations within the gamma band reflect mechanisms of cortical integration. In the light of recently proposed pathophysiological models of schizophrenia, suggesting a disturbance of the functional connectivity within distributed neural networks, it has been hypothesized that abnormalities in the gamma band underlie perceptual and cognitive dysfunctions in patients with schizophrenia. In the present study we investigated evoked and induced 40-Hz gamma power as well as frontoparietal and frontotemporal event-related coherence in patients with deficit and nondeficit schizophrenia and in matched healthy controls. In patients, correlations between gamma oscillations and psychopathological dimensions were also investigated. A reduction of both induced gamma power and event-related coherence was observed in patients with nondeficit schizophrenia, but not in those with deficit schizophrenia. Our findings support the hypothesis that deficit and nondeficit schizophrenia represent separate disease entities, suggesting the presence of a poor integration of the neuronal activity within distributed neural network only in the subgroup of schizophrenic patients without primary and persistent negative symptoms. Associations between an excess of gamma oscillations and psychopathological dimensions were observed, suggesting that abnormal thoughts, behaviors and perceptions might be related to the formation of inappropriate neural connections.

Hemispheric lateralization patterns and psychotic experiences in healthy subjects

The hypothesis that psychotic experiences in healthy subjects are associated with a dysfunction of the right hemisphere is supported by some, but not all, available studies. Differences in gender composition of study samples may explain in part the divergent findings. The present study was carried out in 42 healthy, right-handed university students. Scores on the Schizophrenia and Paranoia scales of the Minnesota Multidimensional Personality Inventory-2 were used in correlation analyses and to define a High- and a Low-Psychotic group. Brain Electrical Microstates and Low Resolution Electromagnetic Tomography (LORETA) source analyses of the auditory P300 (P3a and P3b) components of the event-related potential, as well as a battery of neuropsychological tests, were used to assess hemispheric functioning. Scores on the Paranoia scale were positively associated with a leftward shift of the P3a topographic descriptors in females but not in males. When comparing High-Psychotic and Low-Psychotic females, a leftward shift of P3a descriptors and an increased cortical activation in left fronto-temporal areas were observed in the High-Psychotic group. Our results demonstrated gender-related differences in the pattern of hemispheric imbalance associated with psychotic experiences in healthy subjects.

Executive hypercontrol in obsessive–compulsive disorder: electrophysiological and neuropsychological indices

OBJECTIVE

Neuropsychological, brain imaging and electrophysiological research have consistently shown a dysfunction of fronto-striato-thalamic pathways in subjects with obsessive-compulsive disorder (OCD). The functional meaning of the observed dysfunction in the pathogenesis of OCD is still debated. In the present study the hypothesis that it might be related to a hyperactive executive control is explored by means of neuropsychological and electrophysiological measures.

METHODS

Multilead quantitative EEG (QEEG) characteristics and neuropsychological performance on tests exploring executive functions, attention, short-term memory and the ability to learn supraspan recurring sequences were investigated in 32 drug-free patients with DSM-IV OCD. Multilead QEEG characteristics were also investigated in 32 healthy controls, matched with patients for age, gender and handedness.

RESULTS

A decrease of the slow alpha-band power in OCD as compared to healthy subjects was observed. A significant negative correlation between the slow alpha-band power and the time to complete a neuropsychological test exploring executive functions was found: the more reduced the slow alpha-band power, the slower the performance on this test.

CONCLUSIONS

The topographic distribution of the observed QEEG abnormalities, as well as their correlations with neuropsychological indices, suggest an increased activation of frontal networks in OC patients.

SIGNIFICANCE

Study findings support the presence of a hyperactivity of attention/executive control mechanisms in obsessive-compulsive patients.

Neurocognitive functioning in subjects with eating disorders: the influence of neuroactive steroids

BACKGROUND

Neuropsychological studies in subjects with eating disorders (EDs) have reported conflicting findings, which might be accounted for by several confounding variables, including neuroendocrine changes.

METHODS

General abilities, executive functions, attention, and noneffortful learning were assessed in 45 patients with EDs and 45 healthy comparison subjects (HCS). Plasma levels of 17beta-estradiol, cortisol, allopregnanolone, dehydroepiandrosterone and its sulfate metabolite (DHEA and DHEAS) were evaluated in a subsample of patients and HCS. The influence of clinical, demographic, and neuroendocrine variables on neurocognitive performance was explored.

RESULTS

Patients were slower than HCS on noneffortful learning and more accurate on a spatial executive task. DHEA and DHEAS were increased and positively correlated with accuracy on the executive task, while cortisol positively correlated with speed of noneffortful learning.

CONCLUSIONS

A subtle impairment of noneffortful learning is the only neuropsychological deficit in patients with EDs. Changes in neuroactive steroids influence neurocognitive performance.

Statistical analysis of hippocampal asymmetry in schizophrenia

The asymmetry of brain structures has been studied in schizophrenia to better understand its underlying neurobiology. Brain regions of interest have previously been characterized by volumes, cross-sectional and surface areas, and lengths. Using high-dimensional brain mapping, we have developed a statistical method for analyzing patterns of left-right asymmetry of the human hippocampus taken from high-resolution MR scans. We introduce asymmetry measures that capture differences in the patterns of high-dimensional vector fields between the left and right hippocampus surfaces. In 15 pairs of subjects previously studied (J. G. Csernansky et al., 1998, Proc. Natl. Acad. Sci. USA 95, 11406-11411). we define the difference in hippocampal asymmetry patterns between the groups. Volume analysis indicated a large normative asymmetry between left and right hippocampus (R > L), and shape analysis allowed us to visualize the normative asymmetry pattern of the hippocampal surfaces. We observed that the right hippocampus was wider along its lateral side in both schizophrenia and control subjects. Also, while patterns of hippocampal asymmetry were generally similar in the schizophrenia and control groups, a principal component analysis based on left-right asymmetry vector fields detected a statistically significant difference between the two groups, specifically related to the subiculum.

A review of MRI findings in schizophrenia

After more than 100 years of research, the neuropathology of schizophrenia remains unknown and this is despite the fact that both Kraepelin (1919/1971: Kraepelin, E., 1919/1971. Dementia praecox. Churchill Livingston Inc., New York) and Bleuler (1911/1950: Bleuler, E., 1911/1950. Dementia praecox or the group of schizophrenias. International Universities Press, New York), who first described 'dementia praecox' and the 'schizophrenias', were convinced that schizophrenia would ultimately be linked to an organic brain disorder. Alzheimer (1897: Alzheimer, A., 1897. Beitrage zur pathologischen anatomie der hirnrinde und zur anatomischen grundlage einiger psychosen. Monatsschrift fur Psychiarie und Neurologie. 2, 82-120) was the first to investigate the neuropathology of schizophrenia, though he went on to study more tractable brain diseases. The results of subsequent neuropathological studies were disappointing because of conflicting findings. Research interest thus waned and did not flourish again until 1976, following the pivotal computer assisted tomography (CT) finding of lateral ventricular enlargement in schizophrenia by Johnstone and colleagues. Since that time significant progress has been made in brain imaging, particularly with the advent of magnetic resonance imaging (MRI), beginning with the first MRI study of schizophrenia by Smith and coworkers in 1984 (Smith, R.C., Calderon, M., Ravichandran, G.K., et al. (1984). Nuclear magnetic resonance in schizophrenia: A preliminary study. Psychiatry Res. 12, 137-147). MR in vivo imaging of the brain now confirms brain abnormalities in schizophrenia. The 193 peer reviewed MRI studies reported in the current review span the period from 1988 to August, 2000. This 12 year period has witnessed a burgeoning of MRI studies and has led to more definitive findings of brain abnormalities in schizophrenia than any other time period in the history of schizophrenia research. Such progress in defining the neuropathology of schizophrenia is largely due to advances in in vivo MRI techniques. These advances have now led to the identification of a number of brain abnormalities in schizophrenia. Some of these abnormalities confirm earlier post-mortem findings, and most are small and subtle, rather than large, thus necessitating more advanced and accurate measurement tools. These findings include ventricular enlargement (80% of studies reviewed) and third ventricle enlargement (73% of studies reviewed). There is also preferential involvement of medial temporal lobe structures (74% of studies reviewed), which include the amygdala, hippocampus, and parahippocampal gyrus, and neocortical temporal lobe regions (superior temporal gyrus) (100% of studies reviewed). When gray and white matter of superior temporal gyrus was combined, 67% of studies reported abnormalities. There was also moderate evidence for frontal lobe abnormalities (59% of studies reviewed), particularly prefrontal gray matter and orbitofrontal regions. Similarly, there was moderate evidence for parietal lobe abnormalities (60% of studies reviewed), particularly of the inferior parietal lobule which includes both supramarginal and angular gyri. Additionally, there was strong to moderate evidence for subcortical abnormalities (i.e. cavum septi pellucidi-92% of studies reviewed, basal ganglia-68% of studies reviewed, corpus callosum-63% of studies reviewed, and thalamus-42% of studies reviewed), but more equivocal evidence for cerebellar abnormalities (31% of studies reviewed). The timing of such abnormalities has not yet been determined, although many are evident when a patient first becomes symptomatic. There is, however, also evidence that a subset of brain abnormalities may change over the course of the illness. The most parsimonious explanation is that some brain abnormalities are neurodevelopmental in origin but unfold later in development, thus setting the stage for the development of the symptoms of schizophrenia. Or there may be additional factors, such as stress or neurotoxicity, that occur during adolescence or early adulthood and are necessary for the development of schizophrenia, and may be associated with neurodegenerative changes. Importantly, as several different brain regions are involved in the neuropathology of schizophrenia, new models need to be developed and tested that explain neural circuitry abnormalities effecting brain regions not necessarily structurally proximal to each other but nonetheless functionally interrelated. (ABSTRACT TRUNCATED)

Brain electrical microstates in subjects with panic disorder

Brain electrical microstates represent spatial configurations of scalp recorded brain electrical activity and are considered to be the basic elements of stepwise processing of information in the brain. In the present study, the hypothesis of a temporo-limbic dysfunction in panic disorder (PD) was tested by investigating the topographic descriptors of brain microstates, in particular the one corresponding to the Late Positive Complex (LPC), an event-related potential (ERP) component with generators in these regions. ERPs were recorded in PD patients and matched healthy subjects during a target detection task, in a central (CC) and a lateral condition (LC). In the CC, a leftward shift of the LPC microstate positive centroid was observed in the patients with PD versus the healthy control subjects. In the LC, the topographic descriptor of the first microstate showed a rightward shift, while those of both the second and the fourth microstate, corresponding to the LPC, revealed a leftward shift in the PD patients versus the healthy control subjects. These findings indicate an overactivation of the right hemisphere networks involved in early visual processing and a hypoactivation of the right hemisphere circuits involved in LPC generators in PD. In line with this interpretation, the abnormal topography of the LPC microstate, observed in the CC, was associated with a worse performance on a test exploring right temporo-hippocampal functioning. Topographical abnormalities found for the LPC microstate in the LC were associated with a higher number of panic attacks, suggesting a pathogenetic role of the right temporo-hippocampal dysfunction in PD.

Brain hemispheric organization, anxiety, and psychoses

Abnormalities of brain hemispheric organization have been found in a variety of psychiatric disorders. Despite the great amount of data collected and the number of theoretical models elaborated, the role of these abnormalities in the pathogenesis of these disorders remains controversial. This article briefly reviews current concepts of hemispheric functioning, discusses the role of abnormalities of brain hemispheric organization in schizophrenia and in two anxiety disorders (panic disorder and obsessive-compulsive disorder), and outlines a developmental perspective that accounts for the observed abnormalities.

Emotions, brain development, and psychopathologic vulnerability

Emotional reactivity in infancy and early childhood may play a role in the regulation of brain plasticity and hemispheric organization, which has possible implications for vulnerability to psychopathology. Empiric findings demonstrate the role of attachment patterns in emotional reactivity modulation and limbic circuitry shaping.