The relationship between syndromes of the psychotic illness and familial liability to schizophrenia and major mood disorders

INTREPID II: protocol for a multistudy programme of research on untreated psychosis in India, Nigeria and Trinidad

INTRODUCTION

There are few robust and directly comparable studies of the epidemiology of psychotic disorders in the Global South. INTREPID II is designed to investigate variations in untreated psychotic disorders in the Global South in (1) incidence and presentation (2) 2-year course and outcome, (3) help-seeking and impact, and (4) physical health.

METHODS

INTREPID II is a programme of research incorporating incidence, case-control and cohort studies of psychoses in contiguous urban and rural areas in India, Nigeria and Trinidad. In each country, the target samples are 240 untreated cases with a psychotic disorder, 240 age-matched, sex-matched and neighbourhood-matched controls, and 240 relatives or caregivers. Participants will be followed, in the first instance, for 2 years. In each setting, we have developed and are employing comprehensive case-finding methods to ensure cohorts are representative of the target populations. Using methods developed during pilot work, extensive data are being collected at baseline and 2-year follow-up across several domains: clinical, social, help-seeking and impact, and biological.

ETHICS AND DISSEMINATION

Informed consent is sought, and participants are free to withdraw from the study at any time. Participants are referred to mental health services if not already in contact with these and emergency treatment arranged where necessary. All data collected are confidential, except when a participant presents a serious risk to either themselves or others. This programme has been approved by ethical review boards at all participating centres. Findings will be disseminated through international conferences, publications in international journals, and through local events for key stakeholders.

Structure and neural mechanisms of catatonia

Catatonia is a psychomotor syndrome associated with several psychiatric and medical conditions. Psychomotor signs range from stupor to agitation, and include pathognomonic features such as verbigeration and waxy flexibility. Disturbances of volition led to the classification of catatonia as a subtype of schizophrenia, but changes in nosology now recognise the high prevalence in mood disorders, overlap with delirium, and comorbidity with medical conditions. Initial psychometric studies have revealed three behavioural factors, but the structure of catatonia is still unknown. Evidence from brain imaging studies of patients with psychotic disorders indicates increased neural activity in premotor areas in patients with hypokinetic catatonia. However, whether this localised hyperactivity is due to corticocortical inhibition or excess activity of inhibitory corticobasal ganglia loops is unclear. Current treatment of catatonia relies on benzodiazepines and electroconvulsive therapy-both effective, yet unspecific in their modes of action. Longitudinal research and treatment studies, with neuroimaging and brain stimulation techniques, are needed to advance our understanding of catatonia.

Dissecting the catatonia phenotype in psychotic and mood disorders on the basis of familial-genetic factors

BACKGROUND

This study examines the familial aggregation (familiality) of different phenotypic definitions of catatonia in a sample of multiplex families with psychotic and mood disorders.

METHODS

Participants were probands with a lifetime diagnosis of a DSM-IV functional psychotic disorder, their parents and at least one first-degree relative with a psychotic disorder. The study sample included 441 families comprising 2703 subjects, of whom 1094 were affected and 1609 unaffected. Familiality (h²) was estimated by linear mixed models using family membership as a random effect, with h² indicating the portion of phenotypic variance accounted for by family membership.

RESULTS

Familiality estimates highly varied for individual catatonia signs (h²=0.17-0.65), principal component analysis-derived factors (h²=0.29-0.49), number of catatonia signs present (h²=0.03-0.43) and severity of the catatonia syndrome (h²=0.25-0.59). Phenotypes maximizing familiality estimates included individual signs (mutism and rigidity, both h²=0.65), presence of ≥5 catatonia signs (h²=0.43), a classical catatonia factor (h²=0.49), a DSM-IV catatonia syndrome at a severity level of moderate or higher (h²=0.59) and the diagnostic construct of psychosis with prominent catatonia features (h²=0.56). Familiality estimates of a DSM-IV catatonia syndrome did not significantly differ across the diagnostic categories of psychotic and mood disorders (h²=0.40-0.47).

CONCLUSIONS

The way in which catatonia is defined has a strong impact on familiality estimates with some catatonia phenotypes exhibiting substantial familial aggregation, which may inform about the most adequate phenotypes for molecular studies. From a familial-genetic perspective, the catatonia phenotype in psychotic and mood disorders has a transdiagnostic character.

Schizophrenia heterogeneity revisited: Clinical, cognitive, and psychosocial correlates of statistically-derived negative symptoms subgroups

Traditional efforts to delineate the clinical heterogeneity of schizophrenia have been unsuccessful because of the absence of a valid, stable, and meaningful subtyping scheme. A clinically-informed nosology supported by multivariate statistical classification methods may provide a better approach for classifying schizophrenia. The goals of the current study were to 1) use multivariate classification methods to validate a clinical subtyping scheme based on the profile of negative symptoms; and 2) following validation to contrast the statistically-derived subgroups to ascertain distinguishing demographic, clinical, cognitive, and functional characteristics. In the current study, 706 people with schizophrenia completed measures of positive and negative symptoms, premorbid adjustment, cognition, and psychosocial functioning. Latent class analysis served to identify the number of negative symptom subgroups in schizophrenia. Next, statistical classification methods-Bayes Theorem and the Base Rate Classification Technique-were used to assign participants into the identified subgroups. Subgroups were compared on external validation variables not used in the classification process via logistic regression and discriminant function analysis. Latent class analysis supported a three-class model of schizophrenia that included deficit, persistent, and transient negative symptom subgroups. Posthoc comparisons showed that demographic characteristics, positive symptoms, premorbid adjustment, and cognitive profiles can distinguish the schizophrenia subgroups with moderate accuracy. The deficit subgroup had the greatest impairments in psychosocial functioning and quality of life variables. Findings suggest that schizophrenia encapsulates qualitatively distinct negative symptom subgroups that differ in their demographic, symptomatic, neuropsychological, and functional profiles. Schizophrenia heterogeneity reflects a combination of non-arbitrary subgroups and severity-based differences in negative symptoms.

Symptom profile and short term outcome of catatonia: an exploratory clinical study

BACKGROUND

Catatonia is a potentially life-threatening but treatable neuropsychiatric condition. Although considered more common in low income countries, data is particularly sparse in these settings. In this study we explore the symptomatology, treatment, and short-term outcome of catatonia in Ethiopia, a low income country.

METHODS

The study was a prospective evaluation of patients admitted with a DSM-IV diagnosis of catatonia. Diagnosis of Catatonia and its severity were further assessed with the Bush-Francis Catatonia Rating Scale (BFCRS).

RESULTS

Twenty participants, 5 male and 15 female, were included in the study: 15 patients (75 %) had underlying mood disorders, 4 patients (20 %) had schizophrenia and 1 patient (5 %) had general medical condition. The most common catatonic symptoms, occurring in over two-thirds of participants, were mutism, negativism, staring and immobility (stupor). Eighteen (90 %) of the twenty patients were on multiple medications. Antipsychotics were the most commonly prescribed medications. ECT was required in seven patients (35.0 %). Dehydration, requiring IV rehydration, and infections were the most important complications ascribed to the catatonia. These occurred in seven patients (25 %). Almost all patients (n = 19/20) were discharged with significant improvement.

CONCLUSION

This study supports the growing consensus that catatonia is most often associated with mood disorders. Overall prognosis appears very good although the occurrence of life-threatening complications underlines the serious nature of catatonia. This has implication for "task-shifted" service scale up plans, which aim to improve treatment coverage by training non-specialist health workers to provide mental health care in low income countries. Further larger scale studies are required to clarify the nature and management, as well as, service requirements for catatonia.

Familial liability to schizophrenia and mood disorders and cognitive impairment in psychosis

Schizophrenia and other psychoses are complex disorders with high rates of cognitive impairment and a considerable degree of genetic and environmental influence on its etiology. Whether cognitive impairment is related to dimensional scores of familial liability is still matter of debate. We conducted a cross-sectional study including 169 patients with psychotic disorders and 26 healthy controls. Attention, memory and executive functions were assessed, and familial loading scores for schizophrenia and mood disorders were calculated. The relationships between familial liability and neuropsychological performance were examined with Spearman׳s correlation coefficients. In addition, patients were classified into three groups by family loading tertiles, and comparisons were performed between the patients in the top and bottom tertiles. Low familial loading scores for schizophrenia showed a significant association with poor executive functioning and delayed visual memory. And these results were also achieved when the subset of psychotic patients in the two extreme tertiles of family loadings of schizophrenia and mood disorders were compared. Low familial liability to schizophrenia seems to be a contributing factor for the severity of cognitive impairment in patients with a broad putative schizophrenia spectrum diagnosis.

Morbidity profile of first-degree relatives of probands with schizophrenia: a comparison with mood disorder and healthy control

PURPOSE

There is a paucity of data on heritability of psychotic disorders in Africa. The study aimed to investigate morbid risk of schizophrenia and mood disorder among first-degree relatives of schizophrenia probands, compared with mood disorder and healthy controls.

METHODS

The study examined 330 first-degree relatives of probands with schizophrenia (n = 50), 350 first-degree relatives of probands with mood disorder (n = 50) and 387 first-degree relatives of healthy control (n = 50). The Schedules for Clinical Assessment in Neuropsychiatry, SCAN was used to ascertain diagnosis in ill subjects. To each subject, a socio-demographic questionnaire was administered. Family history was obtained using the Family History Schedule. Morbid risk estimates were calculated using the Weinberg shorter method.

RESULTS

There was a significant difference between the mean age of relatives of schizophrenia probands compared to mood disorder (p = 0.01, 95 % CI 1.34-9.61) and healthy control (p < 0.01, 95 % CI 1.53-9.84). There were also significant differences between the number of children of schizophrenia probands and the number of children of normal control (p < 0.01, 95 % CI -2.0 to -3.9), as well as the number of deceased first-degree relatives of schizophrenia probands compared to normal control (p = 0.04, 95 % CI 0.01-0.94). Finally, there was a significant difference between the number of first-degree relatives of schizophrenia probands compared to the number of first-degree relatives of healthy control who were below the age of risk for schizophrenia (p = 0.01, 95 % CI -0.12 to -1.27). Morbid risks of 4.38 and 0.39 were obtained for schizophrenia among first-degree relatives of probands with schizophrenia and mood disorder, while first-degree relatives of probands with schizophrenia, mood disorder and healthy control had morbid risks for mood disorder of 0.42, 3.82 and 0.35, respectively.

CONCLUSION

The study revealed excess mortality among first-degree relatives of schizophrenia patients. First-degree relatives of probands with schizophrenia and mood disorder also had higher morbid risks for these psychotic conditions than healthy control with some measure of overlap between the two diagnostic categories.

Is disorganization a feature of schizophrenia or a modifying influence: evidence of covariation of perceptual and cognitive organization in a non-patient sample

A subgroup of people with schizophrenia is characterized by reduced organization in perception, thought, language, and motor functioning, and these impairments covary significantly. While this may reflect multiple expressions of an illness-related core processing impairment, it may also represent the extreme end of an organization-disorganization dimension that is found throughout the general population. In this view, disorganization is a modifying influence on illness expression. To obtain preliminary information on this hypothesis, we examined covariation of perceptual and cognitive organization in a non-patient sample. Subjects completed a battery of perceptual tasks with demonstrated sensitivity to schizophrenia and disorganization, and a battery of questionnaires examining cognitive organization. Our results indicated that level of perceptual organization ability, across multiple tasks, was associated with self-reported levels of cognitive organization on multiple measures. This is thus preliminary evidence for a common process affecting perceptual and cognitive organization in the general population, suggesting that disorganization may reflect a modifying influence mechanism, instead of an illness-related process, in schizophrenia.

Catatonia in DSM-5

Although catatonia has historically been associated with schizophrenia and is listed as a subtype of the disorder, it can occur in patients with a primary mood disorder and in association with neurological diseases and other general medical conditions. Consequently, catatonia secondary to a general medical condition was included as a new condition and catatonia was added as an episode specifier of major mood disorders in DSM-IV. Different sets of criteria are utilized to diagnose catatonia in schizophrenia and primary mood disorders versus neurological/medical conditions in DSM-IV, however, and catatonia is a codable subtype of schizophrenia but a specifier for major mood disorders without coding. In part because of this discrepant treatment across the DSM-IV manual, catatonia is frequently not recognized by clinicians. Additionally, catatonia is known to occur in several conditions other than schizophrenia, major mood disorders, or secondary to a general medical condition. Four changes are therefore made in the treatment of catatonia in DSM-5. A single set of criteria will be utilized to diagnose catatonia across the diagnostic manual and catatonia will be a specifier for both schizophrenia and major mood disorders. Additionally, catatonia will also be a specifier for other psychotic disorders, including schizoaffective disorder, schizophreniform disorder, brief psychotic disorder, and substance-induced psychotic disorder. A new residual category of catatonia not otherwise specified will be added to allow for the rapid diagnosis and specific treatment of catatonia in severely ill patients for whom the underlying diagnosis is not immediately available. These changes should improve the consistent recognition of catatonia across the range of psychiatric disorders and facilitate its specific treatment.

Definition and description of schizophrenia in the DSM-5

Although dementia praecox or schizophrenia has been considered a unique disease for over a century, its definitions and boundaries have changed over this period and its etiology and pathophysiology remain elusive. Despite changing definitions, DSM-IV schizophrenia is reliably diagnosed, has fair validity and conveys useful clinical information. Therefore, the essence of the broad DSM-IV definition of schizophrenia is retained in DSM-5. The clinical manifestations are extremely diverse, however, with this heterogeneity being poorly explained by the DSM-IV clinical subtypes and course specifiers. Additionally, the boundaries of schizophrenia are imprecisely demarcated from schizoaffective disorder and other diagnostic categories and its special emphasis on Schneiderian "first-rank" symptoms appears misplaced. Changes in the definition of schizophrenia in DSM-5 seek to address these shortcomings and incorporate the new information about the nature of the disorder accumulated over the past two decades. Specific changes in its definition include elimination of the classic subtypes, addition of unique psychopathological dimensions, clarification of cross-sectional and longitudinal course specifiers, elimination of special treatment of Schneiderian 'first-rank symptoms', better delineation of schizophrenia from schizoaffective disorder, and clarification of the relationship of schizophrenia to catatonia. These changes should improve diagnosis and characterization of individuals with schizophrenia and facilitate measurement-based treatment and concurrently provide a more useful platform for research that will elucidate its nature and permit a more precise future delineation of the 'schizophrenias'.

Testing the hypothesis that formal thought disorders are severe mood disorders

BACKGROUND

It was recently hypothesized by Lake (Schizophrenia Bulletin 2008; 34: 109-117) that Formal Thought Disorder (FTD) can be accounted for by a single disorder that is currently diagnosed as bipolar disorder.

OBJECTIVES

This study aimed to analyze the underlying dimensions of FTD and to examine to what extent FTD factors can be accounted for by clinical distractibility, attentional impairment, severity of mania, and familial liability of bipolar disorder and schizophrenia.

METHODS

Six hundred and sixty inpatients were assessed using a semistructured interview, and FTDs were assessed with the Thought, Language, and Communication scale. "Inattentiveness during Mental Status Testing" item of the Scale for the Assessment of Negative Symptoms scale and a composite mania score were used. The Family History-Research Diagnostic Criteria was used.

RESULTS

FTD is a multidimensional construct comprised at least 5 dimensions: disorganization, verbosity, poverty of speech, idiosyncratic thinking, and blocking. Clinical distractibility loadings split in 2 factors, disorganization and blocking, but it did not load on the mania-related (verbosity) factor. Attentional disturbance was significantly associated with each FTD factor except for idiosyncratic thinking, and these associations were largely independent from the severity of mania. The associations of FTDs with mania and attentional disturbances were independent from each other. FTD factors were not significantly associated with familial liability to bipolar or to schizophrenia.

CONCLUSIONS

Disorganization was the main FTD component. Distractibility was a core feature of FTD factors but it was not specifically accounted for by mania-related attentional impairment. The hypothesis of mutual interdependence between mania and attentional disturbance leading to FTDs could not be confirmed.

Clinical correlates of olfactory hallucinations in schizophrenia

OBJECTIVES. Olfactory hallucinations (OHs) are underrepresented in conventional clinical instruments, infrequently researched, and poorly understood. To advance understanding of OHs, we examined their past-month prevalence and co-occurring symptoms in two datasets. DESIGN. One dataset comprised categorical codes and was examined using homogeneity analysis and logistic regression; the other dataset comprised numeric ratings and was examined using principal components analyses and linear regression. METHOD. The two datasets included: (1) 962 cases with Present State Examination - 9th Edition (PSE-9), codes (recoded present/absent) from the World Health Organization 10 Country (WHO-10) Study and (2) 265 cases with ratings on Scales for Assessing Positive/Negative Symptoms of Schizophrenia (SAPS/SANS). Two PSE-9 items (external- and self-smells) were recoded into a single OH item to examine consistency with the SAPS/SANS dataset, which contained a single OH item. RESULTS. Prevalence of OHs and hallucinations in other modalities differed according to the WHO-10 international centre. Across centres, OHs were present in 13% of the WHO-10 dataset, similar to the 17% prevalence rate in the SAPS/SANS dataset. Referential/control delusions and other hallucinations (particularly, somatic/tactile/gustatory hallucinations) were significant independent correlates of OHs in both datasets. OHs also co-occurred with social anxiety and depression in the WHO-10 dataset, with self-smells being particularly associated with self-depreciation. CONCLUSIONS. Sociocultural factors may modulate the self-reporting and/or detection of OHs and hallucinations in other modalities. Referential/control delusions promote the generation and/or maintenance of OHs independent of factors shared with other hallucinations. OHs and hallucinations of taste, touch, and bodily sensation frequently co-occur. Self-smells warrant sensitive probing.

Heritability estimates for psychotic symptom dimensions in twins with psychotic disorders

Factor analysis of psychotic symptoms frequently results in positive, negative, and disorganized dimensions, but heritability estimates have not yet been reported. Symptom dimensions are usually only measured in individuals with psychotic disorders. Here, it is valuable to assess influences acting via liability to psychosis and independent modifying effects. We estimated heritability for psychotic symptom dimensions, taking account of these issues. Two-hundred-and-twenty-four probandwise twin pairs (106 monozygotic, 118 same-sex dizygotic), where probands had psychoses, were ascertained from the Maudsley Twin Register in London (1948-1993). Lifetime history of DSM-III-R psychotic disorder and psychotic symptom dimensions was assessed from clinical records and research interviews and rated using the Operational Criteria Checklist. Estimates of heritability and environmental components of variance in liability were made with structural equation modeling using a causal-contingent common pathway model adapted for ascertainment from a clinical register. Significant heritability was found for DSM-III-R psychotic disorder (h² = 90%, 95%CI 68-94%) and the disorganized symptom dimension (h² = 84%, 95%CI 18-93%). The heritability for the disorganized dimension remained significant when influences acting through liability to psychosis were set to zero, suggesting that some influences on disorganization are modifying factors independent of psychosis liability. However, the relative extent of modifying factors versus influences acting through psychosis liability could not be clearly determined. To our knowledge, this study provides the first formal evidence of substantive heritability for the disorganized symptom dimension, and suggests that genetic loci influencing disorganization in individuals with psychoses are in some cases different from loci that influence risk of psychotic disorders themselves.

Characterization of affective domains within the nonaffective psychotic disorders

OBJECTIVE

To characterize the affective dimensions of psychopathology in patients with a nonaffective psychosis and to examine their validity against a number of external variables.

METHODS

Five-hundred and thirty-five patients with a lifetime DSM-IV diagnosis of nonaffective psychosis were assessed during the index episode for 22 affective symptoms. These symptoms were factor analyzed and the resulting factor scores were examined for associations with a number of risk factors, illness characteristics, index episode psychopathology and outcome variables.

RESULTS

One-hundred and fifty-six patients (29.1%) met the criteria for a mood disorder during the index episode. Factor analysis of affective symptoms resulted in six factors (mania, core depression, anxiety, retarded depression, dysphoria and lability/mixed) explaining 56% of the variance. Regressions of clinical variables on the six factor scores (p < 0.01 after Bonferroni correction) revealed that mania was related to familial loading to bipolar disorder, shorter duration of the index episode and severity of disorganization symptoms; simple depression was related to suicidal behavior; anxiety was related to psychosocial stressors and reality-distortion symptoms; retarded depression was related to familial loading to major depression, poor premorbid adjustment and negative symptoms; dysphoria was related to violent behavior; lastly, the lability/mixed factor was related to better global functioning, shorter duration of the index episode, better response to treatment and episode polymorphism.

CONCLUSIONS

These results extend the phenomenology of nonaffective psychoses beyond the existing literature to include six affective domains. The validity of each domain is supported by their differential association pattern with illness-related variables.

Twin study refining psychotic symptom dimensions as phenotypes for genetic research

We investigated which psychotic symptom dimensions are likely to be most useful as phenotypes for genetic linkage and association studies. Two hundred twenty-four probandwise twin pairs (106 monozygotic,118 same-sex dizygotic), where probands had psychosis, were ascertained from the Maudsley Twin Register in London. Dimensions were defined as ordinal symptom scores using the OPCRIT checklist, based on previous factor analyses of this and other samples. To qualify as a potentially useful phenotype, dimensions had to show (a) a satisfactory polychoric model fit and significant within-pair correlation in MZ pairs concordant for DSM-III-R psychosis and (b) that they could not be better defined in terms of other combinations of relevant symptoms, single symptoms, or dichotomized dimension scores. Relationships between dimension scores in twin probands and risk of psychosis in co-twins were also investigated. None of the positive or negative dimensions satisfied the phenotypic criteria. The disorganized dimensions showed significant and substantial correlations which maximized for a narrow definition. Combined negative/disorganized dimensions also showed significant and substantial correlations, but did not have advantages over disorganized dimensions. None of the dimensions were significant predictors of psychosis risk in co-twins. We conclude that, of the dimensions analyzed, the narrow disorganized dimension shows most promise as a phenotype for molecular genetic research.

Correlation and familial aggregation of dimensions of psychosis in affected sibling pairs from China

BACKGROUND

A number of studies with conflicting results have examined the familiality of schizophrenia syndromes in Western populations.

AIMS

The objective of this study was to determine, using clinical data from concordant sibling pairs, whether symptom dimensions and other clinical characteristics of schizophrenia show familial aggregation and are therefore potentially useful traits in genetic studies.

METHOD

We measured clinical and demographic features, and symptom dimensions of schizophrenia in 137 families from China who had two or more affected members with schizophrenia. Within-sibling pair correlation was assessed with intraclass correlation coefficient and kappa statistics.

RESULTS

Global functioning, positive, disorganisation and dysphoric symptoms, premorbid schizotypal and schizoid traits, premorbid social adjustment, type and age at illness onset all showed significant evidence of familial aggregation. DSM-IV schizophrenia subtypes were also found to be familial.

CONCLUSIONS

This is the first study in a large non-European population to confirm that schizophrenia dimensions and clinical characteristics show significant familiality, implying possible heritability. This supports their use in the delineation of homogeneous subsets for future genetic studies.