Influence of depressive symptoms and premorbid adjustment on factor structure of phenomenology of schizophrenia: a study from India

Preliminary evidence that fatigue contributes to anhedonia in stable individuals diagnosed with schizophrenia

OBJECTIVES

Anhedonia and fatigue are trans-diagnostic symptoms commonly observed in schizophrenia. Anhedonia is a core negative symptom with a strong relationship with depression and is associated with diminished global functioning. Similarly, fatigue is also associated to depression and research across psychiatric illnesses indicate that fatigue may persist even when primary symptoms are treated. Although fatigue is common in people diagnosed with schizophrenia, it is under studied within this population. The objective of this exploratory study was to investigate the association of fatigue and anhedonia by controlling for depression in a sample of individuals diagnosed with schizophrenia.

METHOD

Fifty-one stable individuals diagnosed with schizophrenia from the University Department of Adult Psychiatry in Montpellier took part in this study. Participants completed questionnaires on fatigue impact and depression, and were assessed for symptom severity. Following data collection, statistical analyses were conducted in order to explore associations between clinical variables and fatigue impact. Based on the results obtained, a hierarchical linear regression was conducted in order to investigate whether fatigue impact contributed to the variance of negative symptoms.

RESULTS

The hierarchical linear regression indicated that when controlling for depression, fatigue impact contributes to ~20% of the variance of anhedonia. Together the social impact of fatigue and depression contribute to 24% of the variation of anhedonia.

CONCLUSION

To the best of our knowledge, this exploratory study is the first to investigate and show that fatigue impact may contribute to anhedonia. We recommend further research to investigate fatigue, its impact on symptomatology, and better categorization of negative symptoms in hopes of developing targeted fatigue treatment interventions.

Negative and depressive symptoms differentially relate to real-world anticipatory and consummatory pleasure in schizophrenia

It has been suggested that schizophrenia is associated with deficits in anticipatory but not consummatory pleasure, though there is mixed support for this hypothesis. As individuals with schizophrenia can experience both negative and depressive symptoms, symptom heterogeneity in this population could contribute to these mixed hedonic findings. Specifically, while some research suggests that negative symptoms of schizophrenia are related to reduced anticipatory but not consummatory pleasure, research on major depressive disorder suggests that depressive symptoms are associated with both decreased anticipatory and consummatory pleasure. Still, it is unclear whether depressive symptoms are associated with experiences of pleasure in schizophrenia as they are in major depressive disorder. Thus, the present study used Ecological Momentary Assessment (four prompts per day over one week) to investigate the unique relationships of negative and depressive symptoms with daily reports of real-world anticipatory and consummatory pleasure in 63 individuals with schizophrenia. Higher negative symptoms related to reduced anticipatory but not consummatory pleasure. On the other hand, higher depressive symptoms related to reductions in both anticipatory and consummatory pleasure. Overall, these results indicate that negative and depressive symptoms are differentially associated with hedonic experience in schizophrenia, and suggest the need to account for the severity of both these symptom types when examining pleasure in this population. Elucidating the nature of these symptom contributions to hedonic impairments could increase causal understanding of these deficits and contribute to the development of more targeted treatments to enhance motivation and pleasure in schizophrenia.

Factor analysis of symptom dimensions (psychotic, affective and obsessive compulsive symptoms) in schizophrenia

AIM

To carryout factor analysis of symptom profile of patients with schizophrenia assessed by using positive and negative syndrome scale (PANSS), Calgary depression rating scale (CDSS), Young mania rating scale (YMRS) and YBOCS checklist.

METHODOLOGY

181 patients of schizophrenia were assessed on PANSS, CDSS, YMRS and YBOCS checklist.

RESULTS

Factor analysis of PANSS yielded 3 factor structure (positive, negative, anxiety). When the items of CDSS were added to the PANSS items, total number of factors increased to 4 with depression emerging as a separate factor. Addition of YMRS to PANSS and CDSS led to emergence of 5 factor model. Further addition of YBOCS checklist led to emergence of a 7 factor model (positive, depressive, obsessive compulsive, negative, manic, anxiety and obsessive compulsive-2), which explained 49.85% variance of the data. Positive symptoms emerged as the factor-1. Depressive symptoms loaded on the factor-2, negative symptoms loaded on to factor-4, manic symptoms loaded onto factor-5 and anxiety symptoms loaded onto factor-6. OC symptoms loaded onto factor 3 and 7.

CONCLUSIONS

Present study suggests that when multiple scales are used for assessment of various symptoms of schizophrenia, the symptoms separate out into 7 factors. This finding suggests that clinical assessment of schizophrenia should not be limited to core psychotic symptoms only and structured instruments must be used to elicit other symptoms too while monitoring the clinical picture of patients with schizophrenia.

Understanding alterations in serotonin connectivity in a rat model of depression within the monoamine-deficiency and the hippocampal-neurogenesis frameworks

The monoamine-deficiency and the hippocampal-neurogenesis hypotheses of depression propose that alterations in the serotonin system and of hippocampal functionality are critical in the pathogenesis of depression. We measured the alterations in the connectivity level of the raphe nucleus in the chronic mild stress (CMS) rat model of depression using the manganese enhanced MRI method (MEMRI). Manganese ions were injected into the median raphe and their anterograde intracellular propagation was followed. Depression-like behavior was demonstrated using the sucrose preference tests. We show that the raphe's connectivity is differentially altered through chronic stress. In line with the monoamine-deficiency hypothesis, the connectivity of the raphe with the basal ganglia (BG) output nuclei, the hippocampus, the habenula and the entorhinal and insular cortices was reduced in CMS rats, suggesting an overall reduction in raphe excitability. Connectivity reductions were predominantly found in the right hemisphere, strengthening previous evidence pointing at a-symmetric hemispheric involvement in depression. Despite the general reduction in raphe connectivity, enhanced connectivity was found between the raphe and the septum, suggesting that alterations are connection-specific. On the basis of our results - while yet equivocal - we further discuss the possible coupling between the serotonergic and dopaminergic systems and two distinct mechanisms (direct and indirect) in which alterations in raphe connectivity may affect hippocampal dysfunction in chronic stress, thus linking the monoamine-deficiency and the hippocampal-neurogenesis hypotheses.

The emotional characteristics of schizotypy

OBJECTIVE

The aim of this study was to investigate the relationship between emotional traits and schizotypal symptoms and to establish a hypothetical model for the causal relationship between them.

METHODS

Schizotypal symptoms were assessed using the Schizotypal Personality Questionnaire (SPQ), and a total of seven emotional traits considered to be potential risk factors for schizotypy were categorized as emotional disturbances, emotional attenuators or emotional amplifiers. A total of 502 undergraduate students completed the SPQ and other scales.

RESULTS

The result of the present study suggested that the high levels of emotional disturbance in individuals who are prone to schizotypy or psychosis are amplified by their intensity and fluctuation. However, if their emotion attenuating abilities function well, these disturbances can be controlled and the schizotypal symptoms and progression to psychosis can be contained. Discriminant analysis showed that 69.0% of the subjects with many schizotypal symptoms and 80.7% of the subjects with few schizotypal symptoms were correctly classified.

CONCLUSION

The present study suggests the possibility of using emotional traits to identify the risk factors for psychosis.

Increased sensitivity to antidepressants of D3 dopamine receptor-deficient mice in the forced swim test (FST)

Evidence exists for a dopaminergic system dysregulation in mood disorders. In particular, depression may be accompanied by a relative fall of brain dopamine (DA) availability, while the increase of dopamine D2/D3 receptors (D2R/D3R) binding may reflect a compensatory change following primary reduction of mesolimbic DA levels. It is well established that D3Rs, acting as autoreceptors, inhibit DA synthesis and release, although lack of selective compounds have limited the progress in understanding D3Rs role in mood disorders. Aim of this study was to assess the behavioral responses of D3R-deficient (D3(-/-)) mice tested in the forced swim test (FST) and to evaluate their sensitivity to the treatment with different antidepressant drugs. Different groups of mice received one injection of the tricyclic compound, clomipramine (1, 5 and 10 mg/kg) or of one the selective serotonin reuptake inhibitors (SSRIs), paroxetine, sertraline or citalopram (1, 4 and 16 mg/kg), 30 min prior the behavioral test. Vehicle-injected wild type (WT) mice and D3(-/-) animals were used as controls and submitted to the same experimental procedure. In a preliminary experiment, vehicle-injected D3(-/-) mice, but not their littermates, failed to show an increased immobility time in FST as compared to intact controls, suggesting an increased resistance to injection-induced stress in the former. Clomipramine 1 mg/kg failed to affect behavioral responses of both D3(-/-) mice and WT animals. After the 5 mg/kg dose, D3(-/-) and WT mice showed a better performance in FST than vehicle-injected controls, with a lower immobility time exhibited by D3(-/-) mice than that shown by WT animals. No difference was found between WT mice treated with the highest dose of clomipramine (10 mg/kg) and the respective controls, although D3(-/-) mice exhibited a decreased immobility time as compared to vehicle-injected controls. In contrast to WT animals, when treated with 1 mg/kg sertraline and the 4 mg/kg dose of every SSRI D3(-/-) mice exhibited a decreased immobility time in FST in comparison to vehicle-injected controls. Furthermore, 16 mg/kg doses of citalopram, paroxetine or sertraline induced a greater reduction of immobility time in D3(-/-) mice than in WT-treated animals as compared to their respective controls. These data suggest that D3(-/-) mice, as being more resistant to stressful procedure than WT littermates, are more sensitive to antidepressants in FST paradigm than the former. Although the present data do not allow any conclusion on the neurochemical base of this difference, it might be possible that the greater sensitivity to antidepressants depends on a higher DA levels in mesolimbic pathways following the lack of D3Rs.

Persistent negative symptoms in schizophrenia: an overview

Persistent negative symptoms represent an alternative approach for assessing negative symptoms in the context of clinical trials. Persistent negative symptoms are designed to capture those symptoms that lead to functional impairment but are currently understudied and for which there are no currently available effective treatments. Persistent negative symptoms differ from the 2 most commonly used approaches: primary, enduring negative symptoms or deficit symptoms and negative symptoms broadly defined to include negative symptoms, regardless of their etiology or duration. In contrast to deficit symptoms, persistent negative symptoms may include secondary negative symptoms. However, in contrast to negative symptoms broadly defined, the secondary negative symptoms included in the assessment of persistent negative symptoms only include those that have failed to respond to usual treatments for secondary negative symptoms. In consequence, the presence of persistent negative symptoms identifies a patient population with clinically relevant symptomatology, which is larger than the one with the deficit syndrome but less heterogeneous than that captured through the use of a nonrestrictive definition of negative symptoms. This may facilitate the selection of subjects for inclusion into research and efforts to develop new pharmacological treatments and enhance our understanding of a relevant clinical problem. Ultimately, the investigation of the different entities characterized by negative symptoms, such as persistent negative symptoms, and the enhanced understanding of their biological and clinical characteristics may help to unravel the psychopathological and biological heterogeneity of schizophrenia.

Distribution of symptom dimensions across Kraepelinian divisions

BACKGROUND

Dimensional structures are established for many psychiatric diagnoses, but dimensions have not been compared between diagnostic groups.

AIMS

To examine the structure of dimensions in psychosis, to analyse their correlations with disease characteristics and to assess the relative contribution of dimensions v. diagnosis in explaining these characteristics.

METHOD

Factor analysis of the OPCRIT items of 191 Maudsley Family Study patients with schizophrenia, mood disorders with psychosis, schizoaffective disorder, and other psychotic illnesses, followed by regression of disease characteristics from factor scores and diagnosis.

RESULTS

Five factors were identified (mania, reality distortion, depression, disorganisation, negative); all were more variable in schizophrenia than in affective psychosis. Mania was the best discriminator between schizophrenia and affective psychosis; the negative factor was strongly correlated with poor premorbid functioning, insidious onset and worse course. Dimensions explained more of the disease characteristics than did diagnosis, but the explanatory power of the latter was also high.

CONCLUSIONS

Kraepelinian diagnostic categories suffice for understanding illness characteristics, but the use of dimensions adds substantial information.

Anhedonia in schizophrenia: a review of assessment strategies

Anhedonia, the diminished capacity to experience pleasant emotions, is a common, treatment-resistant feature of schizophrenia that is often included among the negative symptoms of this disorder. This selective review describes the 3 most commonly used approaches to assess anhedonia in schizophrenia: interview-based measures, self-report trait questionnaires, and laboratory-based assessments of emotional experience. For each assessment approach, psychometric properties, relationships to other symptoms and features of schizophrenia, and relationships with the other assessment approaches are evaluated. It is concluded that anhedonia can be reliably assessed and constitutes a distinctive, clinically important aspect of schizophrenia that should be included in a comprehensive evaluation of negative symptoms. Current efforts to define more precisely the nature of the hedonic deficit in schizophrenia are discussed, and recommendations for optimal assessment of anhedonia in clinical trials of novel treatments for negative symptoms are provided.

Dopamine, depression and antidepressants

Abstract The relationship between depression and dopamine deficiency in the mesolimbic pathway has been hypothesized for many years. The experimental studies with animal models of depression and the human studies implicate the role of the dopamine system in depression. Not only do dopaminergic receptor agonists, but also antagonists such as olanzapine exhibit antidepressant effects associated with standard antidepressants in patients with treatment-resistant depression. This paradoxical result suggests that further investigations are necessary to understand the role played by dopamine in depression.