Common genetic determinants of schizophrenia and bipolar disorder in Swedish families: a population-based study

BACKGROUND

Whether schizophrenia and bipolar disorder are the clinical outcomes of discrete or shared causative processes is much debated in psychiatry. We aimed to assess genetic and environmental contributions to liability for schizophrenia, bipolar disorder, and their comorbidity.

METHODS

We linked the multi-generation register, which contains information about all children and their parents in Sweden, and the hospital discharge register, which includes all public psychiatric inpatient admissions in Sweden. We identified 9 009 202 unique individuals in more than 2 million nuclear families between 1973 and 2004. Risks for schizophrenia, bipolar disorder, and their comorbidity were assessed for biological and adoptive parents, offspring, full-siblings and half-siblings of probands with one of the diseases. We used a multivariate generalised linear mixed model for analysis of genetic and environmental contributions to liability for schizophrenia, bipolar disorder, and the comorbidity.

FINDINGS

First-degree relatives of probands with either schizophrenia (n=35 985) or bipolar disorder (n=40 487) were at increased risk of these disorders. Half-siblings had a significantly increased risk (schizophrenia: relative risk [RR] 3.6, 95% CI 2.3-5.5 for maternal half-siblings, and 2.7, 1.9-3.8 for paternal half-siblings; bipolar disorder: 4.5, 2.7-7.4 for maternal half-siblings, and 2.4, 1.4-4.1 for paternal half-siblings), but substantially lower than that of the full-siblings (schizophrenia: 9.0, 8.5-11.6; bipolar disorder: 7.9, 7.1-8.8). When relatives of probands with bipolar disorder were analysed, increased risks for schizophrenia existed for all relationships, including adopted children to biological parents with bipolar disorder. Heritability for schizophrenia and bipolar disorder was 64% and 59%, respectively. Shared environmental effects were small but substantial (schizophrenia: 4.5%, 4.4%-7.4%; bipolar disorder: 3.4%, 2.3%-6.2%) for both disorders. The comorbidity between disorders was mainly (63%) due to additive genetic effects common to both disorders.

INTERPRETATION

Similar to molecular genetic studies, we showed evidence that schizophrenia and bipolar disorder partly share a common genetic cause. These results challenge the current nosological dichotomy between schizophrenia and bipolar disorder, and are consistent with a reappraisal of these disorders as distinct diagnostic entities.

The long-term natural history of the weekly symptomatic status of bipolar I disorder

BACKGROUND

To our knowledge, this is the first prospective natural history study of weekly symptomatic status of patients with bipolar I disorder (BP-I) during long-term follow-up.

METHODS

Analyses are based on ongoing prospective follow-up of 146 patients with Research Diagnostic Criteria BP-I, who entered the National Institute of Mental Health (Bethesda, Md) Collaborative Depression Study from 1978 through 1981. Weekly affective symptom status ratings were analyzed by polarity and severity, ranging from asymptomatic, to subthreshold levels, to full-blown major depression and mania. Percentages of follow-up weeks at each level as well as number of shifts in symptom status and polarity during the entire follow-up period were examined. Finally, 2 new measures of chronicity were evaluated in relation to previously identified predictors of chronicity for BP-I.

RESULTS

Patients with BP-I were symptomatically ill 47.3% of weeks throughout a mean of 12.8 years of follow-up. Depressive symptoms (31.9% of total follow-up weeks) predominated over manic/hypomanic symptoms (8.9% of weeks) or cycling/mixed symptoms (5.9% of weeks). Subsyndromal, minor depressive, and hypomanic symptoms combined were nearly 3 times more frequent than syndromal-level major depressive and manic symptoms (29.9% vs 11.2% of weeks, respectively). Patients with BP-I changed symptom status an average of 6 times per year and polarity more than 3 times per year. Longer intake episodes and those with depression-only or cycling polarity predicted greater chronicity during long-term follow-up, as did comorbid drug-use disorder.

CONCLUSIONS

The longitudinal weekly symptomatic course of BP-I is chronic. Overall, the symptomatic structure is primarily depressive rather than manic, and subsyndromal and minor affective symptoms predominate. Symptom severity levels fluctuate, often within the same patient over time. Bipolar I disorder is expressed as a dimensional illness featuring the full range (spectrum) of affective symptom severity and polarity.

Bipolar disorder

Bipolar disorder is a recurrent chronic disorder characterised by fluctuations in mood state and energy. It affects more than 1% of the world's population irrespective of nationality, ethnic origin, or socioeconomic status. Bipolar disorder is one of the main causes of disability among young people, leading to cognitive and functional impairment and raised mortality, particularly death by suicide. A high prevalence of psychiatric and medical comorbidities is typical in affected individuals. Accurate diagnosis of bipolar disorder is difficult in clinical practice because onset is most commonly a depressive episode and looks similar to unipolar depression. Moreover, there are currently no valid biomarkers for the disorder. Therefore, the role of clinical assessment remains key. Detection of hypomanic periods and longitudinal assessment are crucial to differentiate bipolar disorder from other conditions. Current knowledge of the evolving pharmacological and psychological strategies in bipolar disorder is of utmost importance.

Genome-wide association study identifies 30 loci associated with bipolar disorder

Bipolar disorder is a highly heritable psychiatric disorder. We performed a genome-wide association study (GWAS) including 20,352 cases and 31,358 controls of European descent, with follow-up analysis of 822 variants with P < 1 × 10-4 in an additional 9,412 cases and 137,760 controls. Eight of the 19 variants that were genome-wide significant (P < 5 × 10-8) in the discovery GWAS were not genome-wide significant in the combined analysis, consistent with small effect sizes and limited power but also with genetic heterogeneity. In the combined analysis, 30 loci were genome-wide significant, including 20 newly identified loci. The significant loci contain genes encoding ion channels, neurotransmitter transporters and synaptic components. Pathway analysis revealed nine significantly enriched gene sets, including regulation of insulin secretion and endocannabinoid signaling. Bipolar I disorder is strongly genetically correlated with schizophrenia, driven by psychosis, whereas bipolar II disorder is more strongly correlated with major depressive disorder. These findings address key clinical questions and provide potential biological mechanisms for bipolar disorder.

Development and validation of a screening instrument for bipolar spectrum disorder: the Mood Disorder Questionnaire

OBJECTIVE

Bipolar spectrum disorders, which include bipolar I, bipolar II, and bipolar disorder not otherwise specified, frequently go unrecognized, undiagnosed, and untreated. This report describes the validation of a new brief self-report screening instrument for bipolar spectrum disorders called the Mood Disorder Questionnaire.

METHOD

A total of 198 patients attending five outpatient clinics that primarily treat patients with mood disorders completed the Mood Disorder Questionnaire. A research professional, blind to the Mood Disorder Questionnaire results, conducted a telephone research diagnostic interview by means of the bipolar module of the Structured Clinical Interview for DSM-IV.

RESULTS

A Mood Disorder Questionnaire screening score of 7 or more items yielded good sensitivity (0.73) and very good specificity (0.90).

CONCLUSIONS

The Mood Disorder Questionnaire is a useful screening instrument for bipolar spectrum disorder in a psychiatric outpatient population.

The Inventory of Depressive Symptomatology, Clinician Rating (IDS-C) and Self-Report (IDS-SR), and the Quick Inventory of Depressive Symptomatology, Clinician Rating (QIDS-C) and Self-Report (QIDS-SR) in public sector patients with mood disorders: a psychometric evaluation

BACKGROUND

The present study provides additional data on the psychometric properties of the 30-item Inventory of Depressive Symptomatology (IDS) and of the recently developed Quick Inventory of Depressive Symptomatology (QIDS), a brief 16-item symptom severity rating scale that was derived from the longer form. Both the IDS and QIDS are available in matched clinician-rated (IDS-C30; QIDS-C16) and self-report (IDS-SR30; QIDS-SR16) formats.

METHOD

The patient samples included 544 out-patients with major depressive disorder (MDD) and 402 out-patients with bipolar disorder (BD) drawn from 19 regionally and ethnicically diverse clinics as part of the Texas Medication Algorithm Project (TMAP). Psychometric analyses including sensitivity to change with treatment were conducted.

RESULTS

Internal consistencies (Cronbach's alpha) ranged from 0.81 to 0.94 for all four scales (QIDS-C16, QIDS-SR16, IDS-C30 and IDS-SR30) in both MDD and BD patients. Sad mood, involvement, energy, concentration and self-outlook had the highest item-total correlations among patients with MDD and BD across all four scales. QIDS-SR16 and IDS-SR30 total scores were highly correlated among patients with MDD at exit (c = 0.83). QIDS-C16 and IDS-C30 total scores were also highly correlated among patients with MDD (c = 0.82) and patients with BD (c = 0.81). The IDS-SR30, IDS-C30, QIDS-SR16, and QIDS-C16 were equivalently sensitive to symptom change, indicating high concurrent validity for all four scales. High concurrent validity was also documented based on the SF-12 Mental Health Summary score for the population divided in quintiles based on their IDS or QIDS score.

CONCLUSION

The QIDS-SR16 and QIDS-C16, as well as the longer 30-item versions, have highly acceptable psychometric properties and are treatment sensitive measures of symptom severity in depression.

Toward a re-definition of subthreshold bipolarity: epidemiology and proposed criteria for bipolar-II, minor bipolar disorders and hypomania

BACKGROUND

The boundaries of bipolarity have been expanding over the past decade. Using a well characterized epidemiologic cohort, in this paper our objectives were: (1). to test the diagnostic criteria of DSM-IV hypomania, (2). to develop and validate criteria for the definition of softer expressions of bipolar-II (BP-II) disorder and hypomania, (3). to demonstrate the prevalence, clinical validity and comorbidity of the entire soft bipolar spectrum.

METHODS

Data on the continuum from normal to pathological mood and overactivity, collected from a 20-year prospective community cohort study of young adults, were used. Clinical validity was analysed by family history, course and clinical characteristics, including the association with depression and substance abuse.

RESULTS

(1). Just as euphoria and irritability, symptoms of overactivity should be included in the stem criterion of hypomania; episode length should probably not be a criterion for defining hypomania as long as three of seven signs and symptoms are present, and a change in functioning should remain obligatory for a rigorous diagnosis. (2). Below that threshold, 'hypomanic symptoms only' associated with major or mild depression are important indicators of bipolarity. (3). A broad definition of bipolar-II disorder gives a cumulative prevalence rate of 10.9%, compared to 11.4% for broadly defined major depression. A special group of minor bipolar disorder (prevalence 9.4%) was identified, of whom 2.0% were cyclothymic; pure hypomania occurred in 3.3%. The total prevalence of the soft bipolar spectrum was 23.7%, comparable to that (24.6%) for the entire depressive spectrum (including dysthymia, minor and recurrent brief depression).

LIMITATION

A national cohort with a larger number of subjects is needed to verify the numerical composition of the softest bipolar subgroups proposed herein.

CONCLUSION

The diagnostic criteria of hypomania need revision. On the basis of its demonstrated clinical validity, a broader concept of soft bipolarity is proposed, of which nearly 11% constitutes the spectrum of bipolar disorders proper, and another 13% probably represent the softest expression of bipolarity intermediate between bipolar disorder and normality.

Bipolar disorders

Bipolar disorders are a complex group of severe and chronic disorders that includes bipolar I disorder, defined by the presence of a syndromal, manic episode, and bipolar II disorder, defined by the presence of a syndromal, hypomanic episode and a major depressive episode. Bipolar disorders substantially reduce psychosocial functioning and are associated with a loss of approximately 10-20 potential years of life. The mortality gap between populations with bipolar disorders and the general population is principally a result of excess deaths from cardiovascular disease and suicide. Bipolar disorder has a high heritability (approximately 70%). Bipolar disorders share genetic risk alleles with other mental and medical disorders. Bipolar I has a closer genetic association with schizophrenia relative to bipolar II, which has a closer genetic association with major depressive disorder. Although the pathogenesis of bipolar disorders is unknown, implicated processes include disturbances in neuronal-glial plasticity, monoaminergic signalling, inflammatory homoeostasis, cellular metabolic pathways, and mitochondrial function. The high prevalence of childhood maltreatment in people with bipolar disorders and the association between childhood maltreatment and a more complex presentation of bipolar disorder (eg, one including suicidality) highlight the role of adverse environmental exposures on the presentation of bipolar disorders. Although mania defines bipolar I disorder, depressive episodes and symptoms dominate the longitudinal course of, and disproportionately account for morbidity and mortality in, bipolar disorders. Lithium is the gold standard mood-stabilising agent for the treatment of people with bipolar disorders, and has antimanic, antidepressant, and anti-suicide effects. Although antipsychotics are effective in treating mania, few antipsychotics have proven to be effective in bipolar depression. Divalproex and carbamazepine are effective in the treatment of acute mania and lamotrigine is effective at treating and preventing bipolar depression. Antidepressants are widely prescribed for bipolar disorders despite a paucity of compelling evidence for their short-term or long-term efficacy. Moreover, antidepressant prescription in bipolar disorder is associated, in many cases, with mood destabilisation, especially during maintenance treatment. Unfortunately, effective pharmacological treatments for bipolar disorders are not universally available, particularly in low-income and middle-income countries. Targeting medical and psychiatric comorbidity, integrating adjunctive psychosocial treatments, and involving caregivers have been shown to improve health outcomes for people with bipolar disorders. The aim of this Seminar, which is intended mainly for primary care physicians, is to provide an overview of diagnostic, pathogenetic, and treatment considerations in bipolar disorders. Towards the foregoing aim, we review and synthesise evidence on the epidemiology, mechanisms, screening, and treatment of bipolar disorders.

Re-evaluating the prevalence of and diagnostic composition within the broad clinical spectrum of bipolar disorders

Until recently it was believed that no more than 1% of the general population has bipolar disorder. Emerging transatlantic data are beginning to provide converging evidence for a higher prevalence of up to at least 5%. Manic states, even those with mood-incongruent features, as well as mixed (dysphoric) mania, are now formally included in both ICD-10 and DSM-IV. Mixed states occur in an average of 40% of bipolar patients over a lifetime; current evidence supports a broader definition of mixed states consisting of full-blown mania with two or more concomitant depressive symptoms. The largest increase in prevalence rates, however, is accounted for by 'softer' clinical expressions of bipolarity situated between the extremes of full-blown bipolar disorder where the person has at least one manic episode (bipolar I) and strictly defined unipolar major depressive disorder without personal or family history for excited periods. Bipolar II is the prototype for these intermediary conditions with major depressions and history of spontaneous hypomanic episodes; current evidence indicates that most hypomanias pursue a recurrent course and that their usual duration is 1-3 days, falling below the arbitrary 4-day cutoff required in DSM-IV. Depressions with antidepressant-associated hypomania (sometimes referred to as bipolar III) also appear, on the basis of extensive international research neglected by both ICD-10 and DSM-IV, to belong to the clinical spectrum of bipolar disorders. Broadly defined, the bipolar spectrum in studies conducted during the last decade accounts for 30-55% of all major depressions. Rapid-cycling, defined as alternation of depressive and excited (at least four per year), more often arise from a bipolar II than a bipolar I baseline; such cycling does not in the main appear to be a distinct clinical subtype - but rather a transient complication in 20% in the long-term course of bipolar disorder. Major depressions superimposed on cyclothymic oscillations represent a more severe variant of bipolar II, often mistaken for borderline or other personality disorders in the dramatic cluster. Moreover, atypical depressive features with reversed vegetative signs, anxiety states, as well as alcohol and substance abuse comorbidity, is common in these and other bipolar patients. The proper recognition of the entire clinical spectrum of bipolarity behind such 'masks' has important implications for psychiatric research and practice. Conditions which require further investigation include: (1) major depressive episodes where hyperthymic traits - lifelong hypomanic features without discrete hypomanic episodes - dominate the intermorbid or premorbid phases; and (2) depressive mixed states consisting of few hypomanic symptoms (i.e., racing thoughts, sexual arousal) during full-blown major depressive episodes - included in Kraepelin's schema of mixed states, but excluded by DSM-IV. These do not exhaust all potential diagnostic entities for possible inclusion in the clinical spectrum of bipolar disorders: the present review did not consider cyclic, seasonal, irritable-dysphoric or otherwise impulse-ridden, intermittently explosive or agitated psychiatric conditions for which the bipolar connection is less established. The concept of bipolar spectrum as used herein denotes overlapping clinical expressions, without necessarily implying underlying genetic homogeneity. In the course of the illness of the same patient, one often observes the varied manifestations described above - whether they be formal diagnostic categories or those which have remained outside the official nosology. Some form of life charting of illness with colored graphic representation of episodes, stressors, and treatments received can be used to document the uniquely varied course characteristic of each patient, thereby greatly enhancing clinical evaluation.

Clinical course of children and adolescents with bipolar spectrum disorders

CONTEXT

Despite the high morbidity associated with bipolar disorder (BP), few studies have prospectively studied the course of this illness in youth.

OBJECTIVE

To assess the longitudinal course of BP spectrum disorders (BP-I, BP-II, and not otherwise specified [BP-NOS]) in children and adolescents.

DESIGN

Subjects were interviewed, on average, every 9 months for an average of 2 years using the Longitudinal Interval Follow-up Evaluation.

SETTING

Outpatient and inpatient units at 3 university centers.

PARTICIPANTS

Two hundred sixty-three children and adolescents (mean age, 13 years) with BP-I (n = 152), BP-II (n = 19), and BP-NOS (n = 92).

MAIN OUTCOME MEASURES

Rates of recovery and recurrence, weeks with syndromal or subsyndromal mood symptoms, changes in symptoms and polarity, and predictors of outcome.

RESULTS

Approximately 70% of subjects with BP recovered from their index episode, and 50% had at least 1 syndromal recurrence, particularly depressive episodes. Analyses of weekly mood symptoms showed that 60% of the follow-up time, subjects had syndromal or subsyndromal symptoms with numerous changes in symptoms and shifts of polarity, and 3% of the time, psychosis. Twenty percent of BP-II subjects converted to BP-I, and 25% of BP-NOS subjects converted to BP-I or BP-II. Early-onset BP, BP-NOS, long duration of mood symptoms, low socioeconomic status, and psychosis were associated with poorer outcomes and rapid mood changes. Secondary analyses comparing BP-I youths with BP-I adults showed that youths significantly more time symptomatic and had more mixed/cycling episodes, mood symptom changes, and polarity switches.

CONCLUSIONS

Youths with BP spectrum disorders showed a continuum of BP symptom severity from subsyndromal to full syndromal with frequent mood fluctuations. Results of this study provide preliminary validation for BP-NOS.

Switching from 'unipolar' to bipolar II. An 11-year prospective study of clinical and temperamental predictors in 559 patients

BACKGROUND

Given the therapeutic and prognostic importance of the unipolar-bipolar dichotomy, predicting which patients will become bipolar subsequent to index diagnosis of major depressive disorder (MDD) is of paramount clinical significance. We sought to characterize the profile of patients with MDD who would convert to the more subtle bipolar subtype (known as BPII) on the basis of clinical and personality variables obtained during MDD episodes.

METHODS

A total of 559 patients, comprehensively evaluated with the Schedule of Affective Disorders and Schizophrenia and "unipolar" MDD at entry, were administered 17 self-report personality measures. Hypomanic and manic episodes were systematically recorded over a prospective observation period of up to 11 years. We compared 48 converters to BPII (8.6%) with 22 converters to bipolar I (BPI) (3.9%) and the remaining larger group of unipolar patients.

RESULTS

Except for greater acuteness, severity, and psychotic symptomatology, BPI converters were essentially similar to MDD nonconverters. By contrast, BPII converters were robustly distinguished from those with MDD who remained unipolar on the basis of self-report measures along the newly derived factors of Mood Lability, Energy-Activity, and Daydreaming. This profile was associated with early age at onset of MDD and pleomorphic psychopathology beyond the usual affective realm, high rates of substance abuse, as well as educational, marital, and occupational disruption and minor antisocial acts prior to discrete hypomanic episodes. Overall, BPII switchers had a more protracted and tempestuous course with shorter well intervals. "Habitual self" descriptions of temperamental instability during MDD episodes provided useful clinical information for predicting which depressed patients will switch to BPII, attaining a sensitivity of 91% for all three factors combined (23 items); Mood Lability alone (nine items) was the most specific predictor (86%), though of lower sensitivity (42%).

CONCLUSIONS

The BPII subtype is best understood by such lability intruding into, and possibly its accentuation during, depressive episodes, thereby creating an intimate interweaving of trait and state. Clinicians must note that the foregoing temperamental profile appears more fundamental in defining the affective dysregulation of the BPII subtype than hypomanic episodes emphasized in DSM-IV.

The evolving bipolar spectrum. Prototypes I, II, III, and IV

This article argues for the necessity of a partial return to Kraepelin's broad concept of manic-depressive illness, and proposes definitions--and provides prototypical cases--to illustrate the rich clinical phenomenology of bipolar subtypes I through IV. Although considerable evidence supports such extensions of bipolarity encroaching upon the territory of major depressive disorder, further research is needed in this area. From a practice standpoint, the compelling reason for broadening the bipolar spectrum lies in the utility of mood stabilizers as augmentation or monotherapy in the treatment of major depressive disorders with soft bipolar features falling short of the current strict standards for the diagnosis of bipolar II and hypomania in DSM-IV and ICD-10.

The bipolar disorder risk allele at CACNA1C also confers risk of recurrent major depression and of schizophrenia

Molecular genetic analysis offers opportunities to advance our understanding of the nosological relationship between psychiatric diagnostic categories in general, and the mood and psychotic disorders in particular. Strong evidence (P=7.0 × 10(-7)) of association at the polymorphism rs1006737 (within CACNA1C, the gene encoding the α-1C subunit of the L-type voltage-gated calcium channel) with the risk of bipolar disorder (BD) has recently been reported in a meta-analysis of three genome-wide association studies of BD, including our BD sample (N=1868) studied within the Wellcome Trust Case Control Consortium. Here, we have used our UK case samples of recurrent major depression (N=1196) and schizophrenia (N=479) and UK non-psychiatric comparison groups (N=15316) to examine the spectrum of phenotypic effect of the bipolar risk allele at rs1006737. We found that the risk allele conferred increased risk for schizophrenia (P=0.034) and recurrent major depression (P=0.013) with similar effect sizes to those previously observed in BD (allelic odds ratio ∼1.15). Our findings are evidence of some degree of overlap in the biological underpinnings of susceptibility to mental illness across the clinical spectrum of mood and psychotic disorders, and show that at least some loci can have a relatively general effect on susceptibility to diagnostic categories, as currently defined. Our findings will contribute to a better understanding of the pathogenesis of major psychiatric illness, and such knowledge should be useful in providing an etiological rationale for shaping psychiatric nosology, which is currently reliant entirely on descriptive clinical data.

Cyclothymic disorder: validating criteria for inclusion in the bipolar affective group

The authors identified 46 cyclothymic probands from a random pool of 500 psychiatric outpatients and prospectively followed them over a 2-3 year period. They used 50 bipolar patients with a definite history of mania and 50 patients with personality disorders as control groups. Although 66% of the cyclothymic outpatients had previously received the diagnosis of hysteria or sociopathy, their pedigrees were similar to those seen in classical bipolar manic-depressive illness; furthermore, 44% of the cyclothymic group experienced brief hypomanic episodes while taking tricyclic drugs, and 35% developed full-blown hypomanic, manic, or depressive episodes during drug-free follow-up. The authors conclude that these findings provide evidence for a cyclothymic-bipolar spectrum.

The International Society for Bipolar Disorders (ISBD) Task Force report on the nomenclature of course and outcome in bipolar disorders

OBJECTIVES

Via an international panel of experts, this paper attempts to document, review, interpret, and propose operational definitions used to describe the course of bipolar disorders for worldwide use, and to disseminate consensus opinion, supported by the existing literature, in order to better predict course and treatment outcomes.

METHODS

Under the auspices of the International Society for Bipolar Disorders, a task force was convened to examine, report, discuss, and integrate findings from the scientific literature related to observational and clinical trial studies in order to reach consensus and propose terminology describing course and outcome in bipolar disorders.

RESULTS

Consensus opinion was reached regarding the definition of nine terms (response, remission, recovery, relapse, recurrence, subsyndromal states, predominant polarity, switch, and functional outcome) commonly used to describe course and outcomes in bipolar disorders. Further studies are needed to validate the proposed definitions.

CONCLUSION

Determination and dissemination of a consensus nomenclature serve as the first step toward producing a validated and standardized system to define course and outcome in bipolar disorders in order to identify predictors of outcome and effects of treatment. The task force acknowledges that there is limited validity to the proposed terms, as for the most part they represent a consensus opinion. These definitions need to be validated in existing databases and in future studies, and the primary goals of the task force are to stimulate research on the validity of proposed concepts and further standardize the technical nomenclature.

Phenomenology of children and adolescents with bipolar spectrum disorders

CONTEXT

Children and adolescents who present with manic symptoms frequently do not meet the full DSM-IV criteria for bipolar I disorder (BP-I).

OBJECTIVE

To assess the clinical presentation and family history of children and adolescents with BP-I, bipolar II disorder (BP-II), and bipolar disorder not otherwise specified (BP-NOS).

DESIGN

Subjects and their primary caretaker were assessed by semistructured interview, and family psychiatric history was obtained from interview of the primary caretaker.

SETTING

Outpatient and inpatient units at 3 university centers.

PARTICIPANTS

A total of 438 children and adolescents (mean +/- SD age, 12.7 +/- 3.2 years) with BP-I (n = 255), BP-II (n = 30), or BP-NOS (n = 153).

MAIN OUTCOME MEASURES

Lifetime psychiatric history and family history of psychiatric disorders.

RESULTS

Youth with BP-NOS were not diagnosed as having BP-I primarily because they did not meet the DSM-IV duration criteria for a manic or mixed episode. There were no significant differences among the BP-I and BP-NOS groups in age of onset, duration of illness, lifetime rates of comorbid diagnoses, suicidal ideation and major depression, family history, and the types of manic symptoms that were present during the most serious lifetime episode. Compared with youth with BP-NOS, subjects with BP-I had more severe manic symptoms, greater overall functional impairment, and higher rates of hospitalization, psychosis, and suicide attempts. Elevated mood was present in 81.9% of subjects with BP-NOS and 91.8% of subjects with BP-I. Subjects with BP-II had higher rates of comorbid anxiety disorders compared with the other 2 groups and had less functional impairment and lower rates of psychiatric hospitalization than the subjects with BP-I.

CONCLUSIONS

Children and adolescents with BP-II and BP-NOS have a phenotype that is on a continuum with that of youth with BP-I. Elevated mood is a common feature of youth with BP-spectrum illness.

Prevalence, correlates, and comorbidity of bipolar I disorder and axis I and II disorders: results from the National Epidemiologic Survey on Alcohol and Related Conditions

OBJECTIVE

To present nationally representative data on 12-month and lifetime prevalence, correlates, and comorbidity of bipolar I disorder.

METHOD

The data were derived from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N = 43,093). Prevalences and associations of bipolar I disorder with sociodemographic correlates and Axis I and II disorders were determined.

RESULTS

Prevalences of 12-month and lifetime DSM-IV bipolar I disorder were 2.0% (95% CI = 1.82 to 2.18) and 3.3% (95% CI = 2.76 to 3.84), respectively, and no sex differences were observed. The odds of bipolar I disorder were significantly greater among Native Americans, younger adults, and respondents who were widowed/separated/divorced and of lower socioeconomic status and significantly lower among Asians and Hispanics (p < .05). Men were significantly (p < .05) more likely to have unipolar mania and earlier onset and longer duration of manic episodes, while women were more likely to have mixed and major depressive episodes and to be treated for manic, mixed, and major depressive episodes. Bipolar I disorder was found to be highly and significantly related (p < .05) to substance use, anxiety, and personality disorders, but not to alcohol abuse.

CONCLUSION

Bipolar I disorder is more prevalent in the U.S. population than previously estimated, highlighting the underestimation of the economic costs associated with this illness. Associations between bipolar I disorder and Axis I and II disorders were all significant, underscoring the need for systematic assessment of comorbidity among bipolar I patients.

12-month outcome of patients with bipolar disorder following hospitalization for a manic or mixed episode

OBJECTIVE

The authors studied the 12-month course of illness following hospitalization for a manic or mixed episode of bipolar disorder to identify potential outcome predictors.

METHOD

They recruited 134 patients with DSM-III-R bipolar disorder who were consecutively admitted for the treatment of a manic or mixed episode. Diagnostic, symptomatic, and functional evaluations were obtained at the index hospitalization. Patients were reevaluated at 2, 6, and 12 months after discharge to assess syndromic, symptomatic, and functional outcome. Factors associated with outcome were identified by using multivariate analyses.

RESULTS

During the 12-month follow-up period, there were no significant differences in outcome between patients with manic compared with mixed bipolar disorder. Although syndromic recovery occurred in 48% of the overall group, symptomatic recovery occurred in only 26% and functional recovery in only 24%. Predictors of syndromic recovery included shorter duration of illness and full treatment compliance. Medication treatment compliance was inversely associated with the presence of comorbid substance use disorders. Symptomatic and functional recovery occurred more rapidly and in a greater percentage of patients from higher social classes.

CONCLUSIONS

A minority of patients with bipolar disorder achieved a favorable outcome in the year following hospitalization for a manic or mixed episode. Shorter duration of illness, higher social class, and treatment compliance were associated with higher rates of recovery and more rapid recovery.

A neurodevelopmental approach to the classification of schizophrenia

The conventional distinction between schizophrenia and manic depression has received little objective support from recent studies of phenomenology, outcome, or familial homotypy. Instead, much clinical, epidemiological, and morphological evidence suggests that within the broad range of Schneiderian schizophrenia there exists one form (congenital schizophrenia) that can be distinguished from other types, the manifestations of which are confined to adult life. We hypothesize that congenital schizophrenia is a consequence of aberrant brain development during fetal and neonatal life. Such patients show structural brain changes and cognitive impairment, and in their male predominance, early onset, and poor outcome, they reflect Kraepelin's original description of dementia praecox. We contend that adult-onset schizophrenia is itself heterogeneous. One important component is a relapsing and remitting disorder that is more frequent in females than in males, exhibits positive but not negative symptoms, and has much in common etiologically with affective psychosis. There also exists a very-late-onset group in which degenerative brain disorder is implicated.

The prevalent clinical spectrum of bipolar disorders: beyond DSM-IV

Based on the author's work and that of collaborators, as well as other contemporaneous research, this article reaffirms the existence of a broad bipolar spectrum between the extremes of psychotic manic-depressive illness and strictly defined unipolar depression. The alternation of mania and melancholia beginning in the juvenile years is one of the most classic descriptions in clinical medicine that has come to us from Greco-Roman times. French alienists in the middle of the nineteenth century and Kraepelin at the turn of that century formalized it into manic-depressive psychosis. In the pre-DSM-III era during the 1960s and 1970s, North American psychiatrists rarely diagnosed the psychotic forms of the disease; now, there is greater recognition that most excited psychoses with a biphasic course, including many with schizo-affective features, belong to the bipolar spectrum. Current data also support Kraepelin's delineation of mixed states, which frequently take on psychotic proportions. However, full syndromal intertwining of depressive and manic states into dysphoric or mixed mania--as emphasized in DSM-IV--is relatively uncommon; depressive symptoms in the midst of mania are more representative of mixed states. DSM-IV also does not formally recognize hypomanic symptomatology that intrudes into major depressive episodes and gives rise to agitated depressive and/or anxious, dysphoric, restless depressions with flight of ideas. Many of these mixed depressive states arise within the setting of an attenuated bipolar spectrum characterized by major depressive episodes and soft signs of bipolarity. DSM-IV conventions are most explicit for the bipolar II subtype with major depressive and clear-cut spontaneous hypomanic episodes; temperamental cyclothymia and hyperthymia receive insufficient recognition as potential factors that could lead to switching from depression to bipolar I disorder and, in vulnerable subjects, to predominantly depressive cycling. In the main, rapid-cycling and mixed states are distinct. Nonetheless, there exist ultrarapid-cycling forms where morose, labile moods with irritable, mixed features constitute patients' habitual self and, for that reason, are often mistaken for "borderline" personality disorder. Clearly, more formal research needs to be conducted in this temperamental interface between more classic bipolar and unipolar disorders. The clinical stakes, however, are such that a narrow concept of bipolar disorder would deprive many patients with lifelong temperamental dysregulation and depressive episodes of the benefits of mood-regulating agents.

Systematic clinical methodology for validating bipolar-II disorder: data in mid-stream from a French national multi-site study (EPIDEP)

BACKGROUND

This paper presents the methodology and clinical data in mid-stream from a French multi-center study (EPIDEP) in progress on a national sample of patients with DSM-IV major depressive episode (MDE). The aim of EPIDEP is to show the feasibility of validating the spectrum of soft bipolar disorders by practising clinicians. In this report, we focus on bipolar II (BP-II).

METHOD

EPIDEP involves training 48 French psychiatrists in 15 sites; construction of a common protocol based on the criteria of DSM-IV and Akiskal (Soft Bipolarity), as well as criteria modified from the work of Angst (Hypomania Checklist), the Ahearn-Carroll Bipolarity Scale, HAM-D and Rosenthal Atypical Depression Scale; Semi-Structured Interview for Evaluation of Affective Temperaments (based on Akiskal-Mallya), self-rated Cyclothymia Scale (Akiskal), family history (Research Diagnostic Criteria); and prospective follow-up.

RESULTS

Results are presented on 250 (of the 537) MDE patients studied thus far during the acute phase. The rate of BP-II disorder which was 22% at initial evaluation, nearly doubled (40%) by systematic evaluation. As expected from the selection of MDE by uniform criteria, inter-group comparison between BP-II vs unipolar showed no differences on the majority of socio-demographic parameters, clinical presentation and global intensity of depression. Despite such uniformity, key characteristics significantly differentiated BP-II from unipolar: younger age at onset of first depression, higher frequency of suicidal thoughts and hypersomnia during index episode, higher scores on Hypomania Checklist and cyclothymic and irritable temperaments, and higher switching rate under current treatment. Eighty-eight percent of cases assigned to cyclothymic temperament by clinicians (with a cut-off of 10/21 items on self-rated cyclothymia) were recognized as BP-II. Evaluation of this temperament by clinician and patient correlated at a highly significant level (r=0.73; p <0.0001). Cyclothymia and hypomania were also correlated significantly (r=0.51; p < 0.001).

LIMITATION

In a study conducted in diverse clinical settings, it was not possible to assure that clinicians making affective diagnoses were blind to the various temperamental measures. However, bias was minimized by the systematic and/or semi-structured nature of all evaluations.

CONCLUSION

With a systematic search for hypomania, 40% of major depressive episodes were classified as BP-II, of which only half were known to the clinicians at study entry. Cyclothymic temperamental dysregulation emerged as a robust clinical marker of BP-II disorder. These data indicate that clinicians in diverse practice settings can be trained to recognize soft bipolarity, leading to changes in diagnostic practice at a national level.

TEMPS-A: validation of a short version of a self-rated instrument designed to measure variations in temperament

OBJECTIVE

To validate a short English-language version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-autoquestionnaire version (TEMPS-A), a self-report questionnaire designed to measure temperamental variations in psychiatric patients and healthy volunteers. Its constituent subscales and items were formulated on the basis of the diagnostic criteria for affective temperaments (cyclothymic, dysthymic, irritable, hyperthymic, and anxious), originally developed by the first author and his former collaborators. Further item wording and selection were achieved at a later stage through an iterative process that incorporated feedback from clinicians, researchers, and research volunteers.

METHOD

A total of 510 volunteers (284 patients with mood disorders, 131 relatives of bipolar probands, and 95 normal controls) were recruited by advertisement in the newspapers, announcements on radio and television, flyers and newsletters, and word of mouth. All participants were interviewed using the Structured Clinical Interview for DSM-III-R, and completed the 110-item TEMPS-A and the Temperament and Character Inventory (TCI-125). The factorial structure, the alpha coefficients, and the item-total correlations coefficients of the TEMPS-A and the correlation coefficients between the dimensions of the TCI and the TEMPS-A subscales were then determined.

RESULTS

A principal components analysis with a Varimax rotation found that 39 out of the 110 original items of the TEMPS-A loaded on five factors that were interpreted as representing the cyclothymic, depressive, irritable, hyperthymic, and anxious factors. Coefficients alpha for internal consistency were 0.91 (cyclothymic), 0.81 (depressive), 0.77 (irritable), 0.76 (hyperthymic), and 0.67 (anxious) subscales. We found statistically significant positive correlations between all-but the hyperthymic-subscales and harm avoidance. Positive correlations with the hyperthymic and cyclothymic, and novelty seeking and negative correlations with the remaining subscales were also recorded. Other major findings included positive correlations between the hyperthymic and reward dependence, persistence and self-directedness; positive correlation between the self-transcendence and the cyclothymic, hyperthymic and the anxious; and negative correlations between the depressive, cyclothymic, irritable, anxious and cooperativeness.

LIMITATION

As the full-scale anxious temperament was added after the four scales of the TEMPS-A were developed, it has only been evaluated in 345 subjects.

CONCLUSIONS

These data indicate that the TEMPS-A in its shortened version is a psychometrically valid scale with good internal consistency. The proposed five subscale structure is upheld. Concurrent validity against the TCI is shown. Most importantly, for each of the temperaments, we were able to show positive attributes which are meaningful in an evolutionary context, along with traits which make a person vulnerable to mood shifts. This hypothesized dual nature of temperament, which is upheld by our data, is a desirable characteristic for a putative behavioral endophenotype in an oligogenic model of inheritance for bipolar disorder.

Assessing anhedonia in psychiatric patients

In two studies of depressed, manic, schizophrenic, and normal subjects, a scale for measuring the intensity of subjects' pleasureable responses to normally emjoyable situations (the Pleasure Scale) evidenced good internal reliability and moderate agreement with the Chapman Anhedonia Scale and Indexes of depressive symptom severity. Only the depressed patients showed extremely anhedonic responses. Although more than half the depressed patients evidenced pleasure scores in the normal range, about 185 of them seemed more anhedonic than any norma subject. A mixture analysis resolved depressed patient scores into two distinct distributions: a normal-range distribution (88% of depressives) and an extremely anhedonic distribution (12%). The findings provide some support for the existence of a qualitatively distinct subtype of major depression that has been variously defined an "endogenomorphic" or "melancholic."