Mixed depression: a clinical marker of bipolar-II disorder

Psychopathological Dissection of Bipolar Disorder and ADHD: Focussing on Racing Thoughts and Verbal Fluency

In the present study, we propose a review and a synthesis of the work of our group about the phenomenology and the cognitive mechanisms of racing thoughts in bipolar disorder (BD) and ADHD. Contrary to the mainstream idea according to which racing thoughts are pathognomonic of BD, our work suggests that racing thoughts are enhanced in ADHD compared to hypomanic episodes of BD, whereas in euthymic episodes of BD self-reported racing thoughts are similar to the rates reported by healthy controls. Using verbal fluency tasks, we found many similarities between bipolar and ADHD subjects with one clear difference: lexical search strategy in hypomania is based on phonemic similarities rather than semantic-relatedness. However, this distinction observed in this cognitive task is certainly difficult to grasp during a clinical interview aiming to differentiate mild hypomania from combined ADHD presentation. The main landmark to distinguish them remains the episodic nature of bipolar disorders as opposed to the lifelong presentation of ADHD symptoms, a dichotomous view that is not so clear-cut in clinical practice.

Post-traumatic stress disorder and childhood emotional abuse are markers of subthreshold bipolarity and worse treatment outcome in major depressive disorder

Post-traumatic stress disorder (PTSD) and childhood maltreatment (CMT: parental neglect; emotional, physical and sexual abuse) have been linked to bipolar disorder but they are also common in major depressive disorder (MDD). Our objective was to investigate their association with the bipolar spectrum and antidepressant treatment outcome in 482 outpatients with DSM-IV MDD treated in the Combining Medications to Enhance Depression Outcomes trial for 28 weeks Bipolar spectrum score included age of onset <21 years, subthreshold hypomania (a period of elated or irritable mood with at least two concurrent hypomanic symptoms, which did not fulfill DSM criteria for hypomanic/manic episode) and depressive mixed state (DMX). PTSD subjects (n = 107; 22%) had more severe depression (P < 0.0001), work and social impairment (P = 0.0031), comorbid anxiety disorders (P < 0.0001) and increased suicidality (P = 0.0003). Bipolar spectrum score was higher with PTSD comorbidity (P = 0.0063) and childhood emotional abuse (P = 0.0001). PTSD comorbidity was associated with residual suicidality (P = 0.0218) after 6 weeks of antidepressant use whereas childhood emotional abuse [odds ratio (OR), 1.01-2.22], subthreshold hypomania (OR, 1.04-4.09) and DMX (OR, 1.00-4.19) were predictors of mood switch. These results corroborate the role of PTSD and childhood emotional abuse as markers of bipolar spectrum and prognostic factors during antidepressant treatment.

Differential clinical characteristics and possible predictors of bipolarity in a sample of unipolar and bipolar inpatients

Major affective conditions including both unipolar (UD) and bipolar disorders (BD) are associated with significant disability throughout the life course. We aimed to investigate the most relevant socio-demographic/clinical differences between UD and BD subjects. Our sample included 180 inpatients, of which 82 (45.5%) participants were diagnosed with UD and 98 (54.5%) with BD. Relative to UD patients, BD individuals were more likely to report prior psychoactive medications, lifetime psychotic symptoms, nicotine abuse, a reduced ability to provide to their needs, gambling behavior, and fewer nonsuicidal self-harm episodes. Moreover, BD patients were more likely to report severe side effects related to medications, a younger age at illness onset and first hospitalization, higher illness episodes, and longer illness duration in years than UD subjects. In a multivariate logistic analysis accounting for age, gender, and socio-demographic characteristics, a significant positive contribution to bipolarity was found only for higher lifetime psychotic symptoms (β = 1.178; p ≤ .05) and number of illness episodes (β = .155; p ≤ .05). The present findings suggest that specific clinical factors may be used in order to better distinguish between UD and BD subgroups. Further studies are required to replicate these findings in larger samples.

The World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for the Biological Treatment of Bipolar Disorders: Acute and long-term treatment of mixed states in bipolar disorder

OBJECTIVES

Although clinically highly relevant, the recognition and treatment of bipolar mixed states has played only an underpart in recent guidelines. This WFSBP guideline has been developed to supply a systematic overview of all scientific evidence pertaining to the acute and long-term treatment of bipolar mixed states in adults.

METHODS

Material used for these guidelines is based on a systematic literature search using various data bases. Their scientific rigour was categorised into six levels of evidence (A-F), and different grades of recommendation to ensure practicability were assigned. We examined data pertaining to the acute treatment of manic and depressive symptoms in bipolar mixed patients, as well as data pertaining to the prevention of mixed recurrences after an index episode of any type, or recurrence of any type after a mixed index episode.

RESULTS

Manic symptoms in bipolar mixed states appeared responsive to treatment with several atypical antipsychotics, the best evidence resting with olanzapine. For depressive symptoms, addition of ziprasidone to treatment as usual may be beneficial; however, the evidence base is much more limited than for the treatment of manic symptoms. Besides olanzapine and quetiapine, valproate and lithium should also be considered for recurrence prevention.

LIMITATIONS

The concept of mixed states changed over time, and recently became much more comprehensive with the release of DSM-5. As a consequence, studies in bipolar mixed patients targeted slightly different bipolar subpopulations. In addition, trial designs in acute and maintenance treatment also advanced in recent years in response to regulatory demands.

CONCLUSIONS

Current treatment recommendations are still based on limited evidence, and there is a clear demand for confirmative studies adopting the DSM-5 specifier with mixed features concept.

Major depressive disorder with subthreshold hypomania (mixed features): Clinical characteristics of patients entered in a multiregional, placebo-controlled study

Major depressive disorder (MDD) associated with subthreshold hypomanic symptoms (mixed features), has been identified as a distinct nosological entity in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). We identified the predominant manic symptoms present at baseline in a multiregional, placebo-controlled trial involving 211 patients with MDD with mixed features (Clinicaltrials.govNCT01421134). Patients with 2 or 3 DSM-5 criteria defined manic symptoms were eligible for the study. At study baseline, increased talkativeness (pressure to keep talking) and flight of ideas (racing thoughts) were endorsed by approximately 65% of patients and a decreased need for sleep was endorsed by 40% of patients. Approximately 60% of patients also endorsed irritability and distractibility at baseline although these symptoms are not generally counted as part of the "mixed" depression diagnosis as they may overlap with criteria for MDD. Thus, five clinical symptoms characterized the manic presentation in the majority of patients diagnosed as having MDD with "mixed" features in this first placebo-controlled trial examining the use of a psychotropic medication (lurasidone) in this population. Our findings support the designation of MDD with mixed features specifier and suggest that this subpopulation of depressed patients may warrant additional medication beyond antidepressants.

The bipolar spectrum: conceptions and misconceptions

OBJECTIVE

This review aims to address concerns about the potential overinclusiveness and vagueness of bipolar spectrum concepts, and also, concerns about the overlap between bipolar illness and borderline personality.

METHOD

Narrative review based on historical and empirical studies.

RESULTS

Bipolar disorder (BD) and major depressive disorder (MDD) came to be separate entities with the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM III), in contrast to the Kraepelinian manic-depressive insanity (MDI) concept, which included both. The bipolar spectrum concept is a return to this earlier Kraepelinian perspective. Further, very different features differentiate the disease of bipolar illness (family history of bipolar illness, severe recurrent mood episodes with psychomotor activation) from the clinical picture of borderline personality (dissociative symptoms, sexual trauma, parasuicidal self-harm). The term 'disorder' obfuscates an ontological difference between diseases, such as manic-depressive illness, and clinical pictures, such as hysteria/post-traumatic stress disorder/dissociation/borderline personality.

CONCLUSIONS

Bipolar spectrum concepts are historically rooted in Kraepelin's manic-depressive illness concept, are scientifically testable, and can be clearly formulated. Further, they differ in kind from traumatic/dissociative conditions in ways that can be both historically and scientifically established.

Association between the so-called "activation syndrome" and bipolar II disorder, a related disorder, and bipolar suggestive features in outpatients with depression

BACKGROUND

Activation syndrome (AS) is a cluster of symptoms listed by the US Food and Drug Administration as possible suicidality precursors during antidepressant treatment. We aimed to clarify whether AS is associated with bipolar II disorder (BP-II) and its related disorder, i.e., bipolar disorder not otherwise specified (BP-NOS), which are often mistreated as major depressive disorder (MDD), as well as bipolar suggestive features in outpatients with depression.

METHODS

The frequency of AS, bipolar suggestive features, and background variables in consecutive outpatients with a major depressive episode (MDE) due to BP-II/BP-NOS or MDD, who were naturalistically treated with antidepressants, were investigated and analyzed retrospectively.

RESULTS

Of 157 evaluable patients (46 BP-II/BP-NOS, 111 MDD), 39 (24.8%) experienced AS. Patients with BP-II/BP-NOS experienced AS significantly more frequently than patients with MDD (52.2% of BP-II/BP-NOS vs. 13.5% of MDD, p<0.01). Univariate analysis revealed that BP-II/BP-NOS diagnosis, cyclothymic temperament, early age at onset of first MDE, psychiatric comorbidities, and depressive mixed state (DMX) were significantly associated with AS development in the entire sample. Multivariate analysis revealed that BP-II/BP-NOS diagnosis and DMX were independent risk factors for AS.

LIMITATIONS

This is a retrospective and naturalistic study; therefore, patient selection bias could have occurred.

CONCLUSIONS

Cautious monitoring of AS is needed during antidepressant trials in patients with BP-II/BP-NOS. Clinicians should re-evaluate underlying bipolarity when they confront AS. Antidepressants should be avoided for treating a current DMX beyond the unipolar-bipolar dichotomy. Prospective studies are needed to confirm these results.

Bipolar spectrum: a review of the concept and a vision for the future

This paper reviews the bipolar spectrum concept historically and empirically. It describes how the concept derives from Kraepelin, but was lost with DSM-III, which divided the broad manic-depressive illness concept, based on recurrent mood episodes of either polarity, to the bipolar versus unipolar dichotomy, based on allowing non-recurrent mood episodes of only one polarity. This approach followed the views of Karl Leonhard and other critics of Kraepelin. Thus post DSM-III American psychiatry is not neo-Kraepelinian, as many claim, but neo-Leonhardian. The bipolar spectrum approach, as advocated by Akiskal and Koukopoulos first, harkens back to the original broad Kraepelinian view of manic-depressive illness. The evidence for and against this approach is discussed, and common misconceptions, including mistaken claims that borderline personality is similar, are revealed and critiqued.

A comprehensive analysis of features that suggest bipolarity in patients with a major depressive episode: which is the best combination to predict soft bipolarity diagnosis?

BACKGROUND

The study aimed to identify specific predictors of soft bipolarity (bipolar II disorder or bipolar disorder not otherwise specified) in depressed patients and to evaluate the global predictive performance of combinations of these predictors.

METHODS

Subjects included 199 patients with a major depressive episode (MDE) due to soft bipolarity or major depressive disorder. Independent predictors of soft bipolar diagnosis were extracted from 12 previously proposed bipolar features using multiple logistic regression analyses, and the global performance of the combination of these predictors was evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

Recurrent MDEs, family history of bipolar disorders in first-degree relatives, cyclothymic temperament, early age at onset of first MDE, and depressive mixed state were independent predictors of soft bipolarity diagnosis [odds ratio (95% confidence interval): 11.22 (2.19-57.63), 8.82 (1.31-59.15), 7.32 (2.22-24.19), 6.22 (1.58-24.57), and 5.57 (1.91-16.30), respectively]. The area under the ROC curve for the relationship between soft bipolarity diagnosis and the number of these five predictors in each patient was 0.911 (highly accurate). The presence of one or more predictors in each patient resulted in highest sensitivity (92.5%) and good specificity (73.1%), whereas that of two or more predictors resulted in good sensitivity (70.0%) and highest specificity (97.5%) for soft bipolarity diagnosis.

LIMITATIONS

Structured/semistructured interviews were not used. Tools for temperament assessments were different between institutions.

CONCLUSIONS

A combination of these predictors was quite helpful for a precise diagnosis of soft bipolarity in patients with depression.

Late-life bipolar depression due to the soft form of bipolar disorder compared to unipolar depression: an inpatient chart review study

BACKGROUND

Several studies have been conducted regarding the clinical features of the manic state in elderly patients with bipolar disorder; however, little information is available about bipolar depression in these patients, especially depression related to bipolar II disorder (BP-II) and bipolar disorder not otherwise specified (BP-NOS).

METHODS

A chart review study of 87 patients (age > or = 60 years) hospitalized due to a major depressive episode (MDE) was conducted.

RESULTS

Thirty-two (36.8%) and 55 (63.2%) patients were diagnosed with bipolar disorder and major depressive disorder (MDD), respectively. BP-II/BP-NOS accounted for 81.3% of bipolar disorder and 29.9% of MDE. Of the 26 BP-II/BP-NOS patients, 73% had been initially diagnosed with MDD (61.0%) or others (12.0%). Compared to MDD patients, BP-II/BP-NOS patients showed a significantly younger age-at-onset of the first MDE (median, 52 vs. 66 years, p=0.000) and significantly more frequent MDEs (median, 3 vs. 1, p=0.000). The depressed mixed state (DMX) was observed in 61.5% of BP-II/BP-NOS patients in contrast to only 16.4% of MDD patients (p=0.000). The multiple logistic regression analysis revealed that younger age at onset of first MDE and DMX were independent markers of bipolarity.

LIMITATIONS

Certain features were retrospectively specified by a single reviewer.

CONCLUSION

Late-life depression due to BP-II/BP-NOS is generally misdiagnosed, but should never be neglected in elderly inpatients. Some features of the depression suggest bipolarity. In particular, DMX was found to be an independent marker of bipolarity, which supports the mixed nature of this disorder across generations.

Phenomenology of racing and crowded thoughts in mood disorders: a theoretical reappraisal

BACKGROUND

Racing thoughts is a frequent symptom in mood disorders, particularly mixed depressive states. This paper aims to summarize our current knowledge about its phenomenology and frequency in the spectrum of mood disorders, and to offer a new theoretical framework.

METHODS

We made a selective review of original and review papers in Medline and PsychInfo database using the keywords "racing thoughts", "crowded thoughts" and "depressive mixed state" in conjunction with "mood disorders".

RESULTS

In the context of a hypomanic state, "racing thoughts" may appear as a result from an excessive production of thoughts, moving quickly from one to the other, and generating a sense of fluidity and pleasantness. In the context of depression, "racing thoughts" are phenomenologically different and better described as "crowded thoughts": they are not only characterized by too many thoughts occurring at the same time in the field of consciousness, but perceived as unpleasant and induce the feeling that ideas are difficult to catch. DISCUSSION AND CLINICAL RELEVANCE: We suggest that crowded thoughts might result from the mixture of a hypomanic component, with an accelerated production of new thoughts (constituting the main source of this symptom in hypomania), and a depressive component, with a deficit of inhibition of previous thoughts (hence making thoughts crowded rather than truly racing). This distinction could help better identify crowded thoughts, and consequently depressive mixed states, which has important implications for therapeutic management. It might also help to further disentangle the psychobiological processes which contribute to the complexity of mood disorders.

Impact of depressive mixed state in an emergency psychiatry setting: a marker of bipolar disorder and a possible risk factor for emergency hospitalization

BACKGROUND

Depressive mixed state (DMX) has been reported to be one of the most useful clinical markers for bipolar II disorder (BP-II) in the outpatient setting. However, the significance of DMX in emergency psychiatry has not been well studied.

METHODS

A chart review study of 139 patients who were hospitalized in an emergency psychiatric ward with an initial diagnosis of major depressive disorder (MDD).

RESULTS

In 42 (30.2%) patients, the diagnosis was changed to bipolar disorder after a median observation period of 189 days from hospitalization, and of these, 34 were diagnosed as having BP-II. DMX was observed in 56 (40.3%) patients at the time of hospitalization. Compared with patients who remained in MDD, significantly more patients who later developed bipolar disorder had experienced DMX (59.5% vs. 32.0%, p = 0.0044). In multivariate analysis, DMX was one of the independent predictors of conversion to bipolar disorder (OR 2.45, p = 0.037), and the independent predictors for DMX were chronic depression and atypical features (OR 2.85, p = 0.010; OR 3.67, p = 0.046, respectively). In addition, DMX was significantly more frequently observed at emergency hospitalization than at non-emergency hospitalization (48.6% vs. 29.1%, p = 0.0065).

LIMITATIONS

A single reviewer evaluated DMX by chart review.

CONCLUSION

DMX is a useful marker of bipolar disorder (mainly BP-II) in the emergency psychiatric setting and is closely related to emergency hospitalization for mood disorders. To confirm these findings, a prospective study that systematically evaluates DMX is needed.

Pure and mixed manic subtypes: a review of diagnostic classification and validation

OBJECTIVE

To review issues surrounding the diagnosis and validity of bipolar manic states.

METHODS

Studies of the manic syndrome and its diagnostic subtypes were reviewed emphasizing historical development, conceptualizations, formal diagnostic proposals, and validation.

RESULTS

Definitions delineating mixed and pure manic states derive some validity from external measures. DSM-IV and ICD-10 diagnosis of bipolar mixed states are too rigid and less restrictive definitions can be validated. Anxiety is a symptom often overlooked in diagnosis of manic subtypes and may be relevant to the mixed manic state. The boundary for separation of mixed mania and depression remains unclear. A 'pure' non-psychotic manic state similar to Kraepelin's 'hypomania' has been observed in several independent studies.

CONCLUSIONS

Issues surrounding diagnostic subtyping of manic states remain complex and the debates surrounding categorical versus dimensional approaches continue. To the extent that categorical approaches for mixed mania diagnosis are adopted, both DSM-IV and ICD-10 are too rigid. Inclusion of non-specific symptoms in definitions of mixed mania, such as psychomotor agitation, does not facilitate and may hinder the diagnostic separation of pure and mixed mania. The inclusion of a diagnostic seasonal specifier for DSM-IV, which is currently based on seasonal patterns for depression might be expanded to include seasonal patterns for mania. Boundaries between subtypes may be 'fuzzy' rather than crisp, and graded approaches could be considered. With the continued development of new tools, such as imaging and genetics, alternative approaches to diagnosis other than the purely symptom-centric paradigms might be considered.

Frequency of dysphoria and mixed states

BACKGROUND

Mixed states are a complex entity in the field of mood disorders. Dysphoria has been advocated as an important clinical dimension of mixed states. The objective of this work is to study the frequency of dysphoria within a population of patients with DSM-IV major depressive and/or manic episodes and to determine if it may help establish diagnostic criteria for subthreshold cases of depressive or manic mixed states.

SAMPLING AND METHODS

A total of 165 patients were assessed using the Mini International Neuropsychiatric Interview complemented by a section defining dysphoria as a constellation of 3 among 4 symptoms (inner tension, irritability, aggressive behavior and hostility).

RESULTS

When classifying patients according to the number of symptoms of the opposite polarity, changes in the frequency of dysphoria revealed a clear contrast between the 2 opposite manic and depressive poles and the full mixed state (DSM-IV definition). The frequency of dysphoria was 17.5% in pure depression, 22.7% in pure mania and 73.3% in full mixed state. Two threshold effects were identified: (1) the frequency of dysphoria increased from 17.5 to 61.1% (p = 0.002) when the number of manic symptoms in DSM-IV depressed patients increased from 0 to 1, and (2) dysphoria increased from 14.3 to 69.2% (p = 0.057) when the number of depressive symptoms increased from 2 to 3 in DSM-IV manic patients.

CONCLUSION

Dysphoria is strongly but not necessarily associated with mixed states. When used as a clinical marker for mixed states, dysphoria confirms the modern delimitations of sub-threshold mixed states by specifying the required number of symptoms of the opposite polarity (which could be lower for depressive mixed states than for manic mixed states). The study has limitations related to the inclusion of patients who are not drug-free, to the definition of dysphoria and to the sample size.

Testing predictors of bipolar-II disorder with a 2-day minimum duration of hypomania

The study's aim was to find if features often reported to distinguish bipolar and depressive disorders could predict bipolar-II disorder (BP-II). Consecutive major depressive episode (MDE) outpatients, including 284 with BP-II and 196 with major depressive disorder (MDD), were interviewed with the Structured Clinical Interview for DSM-IV, Hypomania Interview Guide, and Family History Screen, in a private practice. The minimum duration of past hypomania was 2 days. Mixed depression was defined as an MDE plus three or more intradepressive, non-euphoric hypomanic symptoms. BP-II predictors were early onset (<20 years), many recurrences (>4 MDEs), bipolar family history, mixed depression, and atypical depressions. Bipolar family history had the highest positive predictive value (PPV) (80.8%) but low sample frequency (32.7%); early onset had high PPV (75.2%) and a sample frequency of 37.0%; many recurrences had the highest frequency (70.4%) but the lowest PPV (66.5%). Combinations of three or more predictors had high PPV (79.0%) and a sample frequency of 46.6%. Predictors and combinations of predictors may correctly identify 75% to 80% of BP-II, reducing the misdiagnosis of BP-II as MDD (by prompting careful probing for hypomania history), and improving treatment of depression (as antidepressants alone may worsen BP-II course). As PPV is related to disease prevalence, findings need to be replicated in different settings.

Is there a continuity between bipolar and depressive disorders?

BACKGROUND

Recent studies questioned the current categorical split of mood disorders into bipolar disorders (BP) and depressive disorders (MDD).

METHODS

Medline database search of papers from the last 10 years on the categorical-dimensional classification of mood disorders. Various combinations of the following key words were used: mood disorders, bipolar, unipolar, major depressive disorder, spectrum, category/categorical, classification, continuity. Only English language clinical papers were included, review papers were excluded, similar papers selected by quality. The number of papers found was 1,141. The number of papers selected was 109.

RESULTS

The continuity/spectrum between BP (mainly BP-II) and MDD was supported by the following findings:(1) high frequency of mixed states (mixed mania, mixed hypomania, mixed depression, i.e. co-occurring depression and noneuphoric manic/hypomanic symptoms) because opposite polarity symptoms in the same episode do not support a hypomania/mania-depression splitting; (2) MDD was the most common mood disorder in BP probands' relatives; (3) no bimodal distribution of distinguishing symptoms between BP and MDD; (4) bipolar signs not uncommon in MDD; (5) many MDD shifting to BP; (6) many lifetime manic/hypomanic symptoms in MDD; (7) correlation between lifetime manic/hypomanic symptoms and MDD symptoms; (8) hypomania factors in MDD; (9) MDD often recurrent; (10) similar cognitive style. The categorical distinction between BP (mainly BP-I) and MDD was supported by the following findings: (1) BP more common in BP probands' relatives; (2) lower age at BP onset; (3) females as common as males in BP-I, more common than males in MDD; (4) BP-I depression more atypical and retarded, MDD depression more sleepless and agitated; (5) BP more recurrent.

CONCLUSIONS

Focusing on mood spectrum's extremes (BP-I vs. MDD), a categorical distinction seems supported. Focusing on midway disorders (BP-II and MDD plus bipolar signs), a continuity/spectrum seems supported. Results seem to support both a categorical and a dimensional view of mood disorders.

Challenging the unipolar-bipolar division: does mixed depression bridge the gap?

BACKGROUND

Mixed states, i.e., opposite polarity symptoms in the same mood episode, question the categorical splitting of mood disorders in bipolar disorders and unipolar depressive disorders, and may support a continuum between these disorders. Study aim was to find if there were a continuum between hypomania (defining BP-II) and depression (defining MDD), by testing mixed depression as a 'bridge' linking these two disorders. A correlation between intradepressive hypomanic symptoms and depressive symptoms could support such a continuum, but other explanations of a correlation are possible.

METHODS

Consecutive 389 BP-II and 261 MDD major depressive episode (MDE) outpatients were interviewed, cross-sectionally, with the Structured Clinical Interview for DSM-IV, the Hypomania Interview Guide (to assess intradepressive hypomanic symptoms) and the Family History Screen, by a mood disorders specialist psychiatrist in a private practice. Patients presented voluntarily for treatment of depression when interviewed drug-free and had many subsequent follow-ups after treatment start. Mixed depression (depressive mixed state) was defined as the combination of MDE (depression) and three or more DSM-IV intradepressive hypomanic symptoms (elevated mood and increased self-esteem were always absent by definition), a definition validated by Akiskal and Benazzi.

RESULTS

BP-II, versus MDD, had significantly lower age at onset, more recurrences, atypical and mixed depressions, bipolar family history, MDE symptoms and intradepressive hypomanic symptoms. Mixed depression was present in 64.5% of BP-II and in 32.1% of MDD (p=0.000). There was a significant correlation between number of MDE symptoms and number of intradepressive hypomanic symptoms. A dose-response relationship between frequency of mixed depression and number of MDE symptoms was also found.

CONCLUSIONS

Differences on classic diagnostic validators could support a division between BP-II and MDD. Presence of intradepressive hypomanic symptoms by itself, and correlation between intradepressive hypomanic symptoms and depressive symptoms could instead support a continuum. Other explanations of such a correlation are possible. Depending on the method used, a BP-II-MDD continuum could be supported or not.

Mixed depression and the dimensional view of mood disorders

BACKGROUND

Mixed depression (MxD), i.e. depression plus cooccurring noneuphoric manic/hypomanic symptoms, questions the current categorical dividing of mood disorders into bipolar disorders and depressive disorders, and supports a dimensional approach. The study aim was to test a dimensional approach to mood disorders by looking for a progressive grading of age at onset and bipolar family history loading between bipolar II disorder (BP-II) and major depressive disorder (MDD).

METHODS

Consecutive 389 BP-II and 261 MDD major depressive episode outpatients were interviewed (off psychoactive drugs) with the Structured Clinical Interview for DSM-IV, the Hypomania Interview Guide (to assess intradepressive noneuphoric hypomanic symptoms), and the Family History Screen, by a mood disorder specialist psychiatrist in a private practice. BP-II and MDD MxD and non-MxD were compared on age at onset and bipolar family history loading (the diagnostic validators). A dose-response was tested between the number of intradepressive hypomanic symptoms and bipolar family history loading, and a correlation was tested between the number of intradepressive hypomanic symptoms and age at onset.

RESULTS

MxD was present in 64.5% of BP-II and in 32.1% of MDD. There were significant differences in classic diagnostic validators (onset age, bipolar family history). The comparisons between BP-II and MDD MxD and non-MxD on age at onset and bipolar family history found a clear and significant grading in age at onset from BP-II MxD to MDD non-MxD (a progressive increase), and a clear and significant grading in bipolar family history loading from BP-II MxD to MDD non-MxD (a progressive decrease). A dose-response relationship was found between the number of intradepressive hypomanic symptoms and bipolar family history loading. The area under the ROC curve was small. A significant correlation was found between the number of intradepressive hypomanic symptoms and age at onset.

CONCLUSIONS

The presence of MxD in a significant proportion of MDD, the progressive grading of age at onset and bipolar family history from BP-II MxD to MDD non-MxD, the dose-response relationship between intradepressive hypomanic symptoms and bipolar family history loading, and the correlation between intradepressive hypomanic symptoms and age at onset could support a dimensional approach to mood disorders (BP-II and MDD). On the other hand, the significant differences on classic diagnostic validators could support a categorical distinction. A mixed approach (dimensional and categorical) to mood disorders could be supported.

Various forms of depression

The current subtyping of depression is based on the Diagnostic and Statistical Manual of Mental Disorders, 4th ed, Text Revision (DSM-IV-TR) categorical division of bipolar and depressive disorders. Current evidence, however, supports a dimensional approach to depression, as a continuum/spectrum of overlapping disorders, ranging from bipolar I depression to major depressive disorder. Types of depression which have recently been the focus of most research will be reviewed: bipolar II depression, mixed depression, agitated depression, atypical depression, melancholic depression, recurrent brief depression, minor depressive disorder, seasonal depression, and dysthymic disorder. Most research has focused on bipolar II depression, mixed depression (defined by depression and superimposed manic/hypomanic symptoms), and atypical depression. Mixed depression, by its combination of opposite polarity symptoms, has been found to be common by systematic probing for co-occurring manic/hypomanic symptoms. Mixed depression is a treatment challenge for clinicians, because antidepressants alone (ie, not protected by mood-stabilizing agents) may worsen its manic/hypomanic symptoms, such as irritability and psychomotor agitation, which the Food and Drug Administration (FDA) has listed as possible precursors to suicidality.

A continuity between bipolar II depression and major depressive disorder?

BACKGROUND

A recent series of studies has questioned the current categorical split of mood disorders into bipolar and depressive disorders. Mixed states, especially mixed depression (i.e., depression plus co-occurring, noneuphoric, hypomanic symptoms) might support a continuity between bipolar II (BP-II) depression and major depressive disorder (MDD). The aim of the study was to assess the distribution of intradepressive hypomanic symptoms rating between BP-II and MDD depressions. A bi-modal distribution would support a categorical distinction, and no bi-modality would support continuity.

METHODS

Consecutive 389 BP-II and 261 MDD major depressive episode (MDE) outpatients were interviewed (off psychoactive drugs) with the Structured Clinical Interview for DSM-IV, the Hypomania Interview Guide (HIG, to assess intradepressive hypomanic symptoms), and the Family History Screen, by a mood specialist psychiatrist in a private practice. Mixed depression was defined as MDE plus 3 or more intradepressive, noneuphoric hypomanic symptoms, a definition validated by Akiskal and Benazzi. The distribution of intradepressive hypomanic symptoms rating was studied by Kernel density estimate and by histogram.

RESULTS

BP-II depression, versus MDD depression, had significantly lower age at onset, was significantly more likely to be atypical and mixed, had more depression recurrences, and a higher bipolar family history loading. BP-II depression, versus MDD depression, had significantly more irritability, racing/crowded thoughts, distractibility, psychomotor agitation, talkativeness, increased goal-directed activity, and excessive risky activities. HIG scores were significantly higher in BP-II. The distribution of intradepressive hypomanic symptoms rating showed no bi-modality in the entire depression sample.

CONCLUSIONS

Interpretation of study findings relies on the method used to define a categorical disorder. By using classic diagnostic validators (such as family history and age at onset), BP-II and MDD depressions would seem to be distinct disorders. Instead, by using the 'bi-modality' approach, a continuity would seem to be supported. Which of these methods for classification is the best has yet to be shown.

Mood patterns and classification in bipolar disorder

PURPOSE OF REVIEW

The aim of this review is to highlight recent studies that have questioned the current split of mood disorders into the categories of bipolar and depressive disorders.

RECENT FINDINGS

A continuity between bipolar disorders (mainly bipolar II disorder) and major depressive disorder was supported by several lines of evidence: depressive mixed states (mixed depression) and dysphoric (mixed) hypomania (opposite polarity symptoms in the same episode do not support the splitting between mania/hypomania and depression); family history, major depressive disorder is the most common mood disorder in relatives of bipolar probands; lack of points of rarity between the depressive syndromes of bipolar II disorder and major depressive disorder; bipolar features in major depressive disorder; major depressive disorder shifting to bipolar disorders; history of manic/hypomanic symptoms in major depressive disorder and correlation between lifetime manic/hypomanic symptoms and depressive symptoms in major depressive disorder; factors of hypomania inside major depressive disorder; recurrent course of major depressive disorder; depression more common than mania and hypomania in bipolar disorders; trait mood lability in major depressive disorder.

SUMMARY

This review of the recent findings on the relationship between bipolar disorders (especially bipolar II disorder) and depressive disorders seems to support a continuity among mood disorders, and runs against the current classification of mood disorders dividing them into independent categories. Further research is needed in the area, in part because of its possible treatment impact.

The relationship of major depressive disorder to bipolar disorder: continuous or discontinuous?

Recent studies have questioned current diagnostic systems that split mood disorders into the independent categories of bipolar disorders and depressive disorders. The current classification of mood disorders runs against Kraepelin's unitary view of manic-depressive insanity (illness). The main findings of recent studies supporting a continuity between bipolar disorders (mainly bipolar II disorder) and major depressive disorder are presented. The features supporting a continuity between bipolar II disorder and major depressive disorder currently are 1) depressive mixed states (mixed depression) and dysphoric (mixed) hypomania (opposite polarity symptoms in the same episode do not support a splitting of mood disorders); 2) family history (major depressive disorder is the most common mood disorder in relatives of bipolar probands); 3) lack of points of rarity between the depressive syndromes of bipolar II disorder and major depressive disorder; 4) major depressive disorder with bipolar features such as depressive mixed states, young onset age, atypical features, bipolar family history, irritability, racing thoughts, and psychomotor agitation; 5) a high proportion of major depressive disorders shifting to bipolar disorders during long-term follow-up; 6) a high proportion of major depressive disorders with history of manic and hypomanic symptoms; 7) factors of hypomania present in major depressive disorder episodes; 8) recurrent course of major depressive disorder; and 9) depressive symptoms much more common than manic and hypomanic symptoms in the course of bipolar disorders.