Delineation of the clinical picture of Dysphoric/Mixed Hypomania

Investigating racing thoughts via ocular temporal windows: deficits in the control of automatic perceptual processes

BACKGROUND

Racing thoughts have been found in several states of bipolar disorder (BD), but also in healthy populations with subclinical mood alterations. The evaluation of racing thoughts relies on subjective reports, and objective measures are sparse. The current study aims at finding an objective neuropsychological equivalent of racing thoughts in a mixed group of BD patients and healthy controls by using a bistable perception paradigm.

METHOD

Eighty-three included participants formed three groups based on participants' levels of racing thoughts reported via the Racing and Crowded Thoughts Questionnaire. Participants reported reversals in their perception during viewing of the bistable Necker cube either spontaneously, while asked to focus on one interpretation of the cube, or while asked to accelerate perceptual reversals. The dynamics of perceptual alternations were studied both at a conscious level (with manual temporal windows reflecting perceptual reversals) and at a more automatic level (with ocular temporal windows derived from ocular fixations).

RESULTS

The rate of windows was less modulated by attentional conditions in participants with racing thoughts, and most clearly so for ocular windows. The rate of ocular windows was especially high when participants with racing thoughts were asked to focus on one interpretation of the Necker cube and when they received these instructions for the first time.

CONCLUSIONS

Our results indicate that in subjects with racing thoughts automatic perceptual processes escape cognitive control mechanisms. Racing thoughts may involve not only conscious thought mechanisms but also more automatic processes.

Reviewing the diagnostic validity and utility of mixed depression (depressive mixed states)

Objective

To review the diagnostic validity and utility of mixed depression, i.e. co-occurrence of depression and manic/hypomanic symptoms.

Methods

PubMed search of all English-language papers published between January 1966 and December 2006 using and cross-listing key words: bipolar disorder, mixed states, criteria, utility, validation, gender, temperament, depression-mixed states, mixed depression, depressive mixed state/s, dysphoric hypomania, mixed hypomania, mixed/dysphoric mania, agitated depression, anxiety disorders, neuroimaging, pathophysiology, and genetics. A manual review of paper reference lists was also conducted.

Results

By classic diagnostic validators, the diagnostic validity of categorically-defined mixed depression (i.e. at least 2–3 manic/hypomanic symptoms) is mainly supported by family history (the current strongest diagnostic validator). Its diagnostic utility is supported by treatment response (negative effects of antidepressants). A dimensionally-defined mixed depression is instead supported by a non-bi-modal distribution of its intradepression manic/hypomanic symptoms.

Discussion

Categorically-defined mixed depression may have some diagnostic validity (family history is the current strongest validator). Its diagnostic utility seems supported by treatment response.

Psychopathology of Mixed States

Mixed states are frequent clinical pictures in psychiatric practice but are not well described in nosologic systems. Debate exists as to defining mixed states. We review factor and cluster analytical studies and prominent clinical/conceptual models of mixed states. While mania involves standard manic symptoms and depression involves standard depressive symptoms, core additional features of the mixed state are, primarily, psychomotor activation and, secondarily, dysphoria. Those features are more pronounced in mixed mania than in mixed depression but are present in both.

Racing thoughts revisited: A key dimension of activation in bipolar disorder

BACKGROUND

Racing and crowded thoughts are frequently reported respectively in manic and mixed episodes of bipolar disorder (BD). However, questionnaires assessing this symptom are lacking. Here we aimed to investigate racing thoughts across different mood episodes of BD through a self-report questionnaire that we developed, the 34-item Racing and Crowded Thoughts Questionnaire (RCTQ). In addition to assessing its factor structure and validity, we were interested in the RCTQ's ability to discriminate mixed and non-mixed depression.

METHODS

221 BD patients and 120 controls were clinically assessed via the YMRS (mania) and the QIDS-C16 (depression), then fulfilled the RCTQ, rumination, worry, and anxiety measures. Three depression groups were operationalized according to YMRS scores: YMRS scores 2 > 6 and YMRS scores = 1 or 2, for respectively mixed and non-pure depression, and YMRS = 0 for pure-depression.

RESULTS

Confirmatory factor analysis showed that the three-factor model of the RCTQ yielded the best fit indices, which improved after the removal of redundant items, resulting in a 13-item questionnaire. Hypomanic and anxiety symptoms were the main predictors of scores; rumination was not a significant predictor. RCTQ results were similar between mixed groups and non-pure depression, and both were higher than in pure-depression.

LIMITATIONS

Patients' pharmacological treatment might have influenced the results.

CONCLUSIONS

The 13-item RCTQ captures different facets of racing thoughts heightened in hypomanic and mixed states, but also in depression with subclinical hypomanic/activation symptoms (e.g. non-pure depression characterized by enhanced subjective irritability), suggesting that it is particularly sensitive to activation symptoms in BD, and could become a valuable tool in the follow-up of patients.

Current irritability associated with hastened depressive recurrence and delayed depressive recovery in bipolar disorder

Background

Current irritability is associated with greater retrospective and current bipolar disorder (BD) illness severity; less is known about prospective longitudinal implications of current irritability. We examined relationships between current irritability and depressive recurrence and recovery in BD.

Methods

Outpatients referred to the Stanford BD Clinic during 2000–2011 were assessed with the Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation at baseline, and with the Clinical Monitoring Form during follow-up during up to 2 years of naturalistic treatment. Prevalence and clinical correlates of any current irritability in depressed and recovered (euthymic ≥8 weeks) BD patients were assessed. Kaplan–Meier analyses (Log-Rank tests) assessed relationships between current irritability and longitudinal depressive severity, with Cox Proportional Hazard analyses assessing potential mediators.

Results

Recovered BD outpatients with vs. without current irritability had significantly higher rates of 13/19 (68.4 %) other baseline unfavorable illness characteristics/current mood symptoms and hastened depressive recurrence (Log-Rank p = 0.020), driven by lifetime history of anxiety disorder and prior year rapid cycling, and attenuated by history of psychosis. Depressed BD outpatients with vs. without current irritability had significantly higher rates of 7/19 (36.8 %) other unfavorable illness characteristics/current mood symptoms and delayed depressive recovery (Log-Rank p = 0.034), NOT mediated by any assessed parameter.

Limitations

Limited generalizability beyond our predominately white, female, educated, insured American BD specialty clinic sample.

Conclusions

Current irritability was associated with hastened depressive recurrence and delayed depressive recovery in BD. Treatment studies targeting irritability may yield strategies to mitigate increased longitudinal depressive burden.

Phenomenological subtypes of mania and their relationships with substance use disorders

OBJECTIVE

The aim of the present study was to determine the distinct clusters of subtypes among patients with bipolar disorder (BD) and the relationship between the clinical features of BD patients, particularly substance use disorders (SUDs) and the clusters.

METHOD

The present study initially assessed 96 inpatients who were hospitalized in the psychiatric clinic of Bakırköy Prof. Mazhar Osman Training and Research Hospital for Psychiatry and Neurology, for a BD manic episode. All patients were evaluated during the initial 3 days of their admission using the Young Mania Rating Scale (YMRS), the Montgomery-Asberg Depression Rating Scale (MADRS),the Scale for the Assessment of Positive Symptoms (SAPS), the Michigan Alcoholism Screening Test (MAST) and a sociodemographic questionnaire. The factor structures of the psychopathological scale items were determined with factor analyses and based on the factor loadings, cluster analyses were performed. The relationships among the clusters and the clinical variables were then evaluated.

RESULTS

The factor analyses generated three factors: increased psychomotor activity, dysphoria, and psychosis. A hierarchical cluster analysis was applied to the three factor loadings, and revealed that factor 1 (increased psychomotor activity) was high in cluster 1 and that the effects of factors 2 (dysphoria) and 3 (psychosis) were high in cluster 2. Within cluster 1 (Psychomotor elevation), 39% of patients were diagnosed with an alcohol use disorder while 31.6% of patients in the cluster 2 (dysphoric-psychotic) were diagnosed with both alcohol and cannabis use disorders. Within cluster 2 (dysphoric-psychotic), 47.4% of patients had one suicide attempt and 21.1% of patients had two or more attempts during their lifetime.

CONCLUSION

There was a significant difference in the presence of SUDs between patients with psychomotor elevation and patients in dysphoric-psychotic cluster. This may be point out that pure manic patients with BD self-medicate using the sedative effects of alcohol and the causal relationship between cannabis and psychosis. Using a dimensional approach to study BD may enhance detection of the biological correlates of BD and improve the treatment and outcomes of the disorder.

First controlled treatment trial of bipolar II hypomania with mixed symptoms: quetiapine versus placebo

OBJECTIVES

To compare the efficacy and safety of adjunctive quetiapine (QTP) versus placebo (PBO) for patients with bipolar II disorder (BDII) currently experiencing mixed hypomanic symptoms in a 2-site, randomized, placebo-controlled, double-blind, 8-week investigation.

METHODS

Participants included 55 adults (age 18-65 years) who met criteria for BDII on the Structured Clinical Interview for DSM-IV-TR (SCID). Entrance criteria included a stable medication regimen for ≥2 weeks and hypomania with mixed symptoms (>12 on the Young Mania Rating Scale [YMRS] and >15 on the Montgomery Asberg Depression Rating Scale [MADRS] at two consecutive visits 1-3 days apart). Participants were randomly assigned to receive adjunctive quetiapine (n=30) or placebo (n=25).

RESULTS

Adjunctive quetiapine demonstrated significantly greater improvement than placebo in Clinical Global Impression for Bipolar Disorder Overall Severity scores (F(1)=10.12, p=.002) and MADRS scores (F(1)=6.93, p=.0138), but no significant differences were observed for YMRS scores (F(1)=3.68, p=.069). Side effects of quetiapine were consistent with those observed in previous clinical trials, with sedation/somnolence being the most common, occurring in 53.3% with QTP and 20.0% with PBO.

CONCLUSIONS

While QTP was significantly more effective than PBO for overall and depressive symptoms of BDII, there was no significant difference between groups in reducing symptoms of hypomania. Hypomania improved across both groups throughout the study.

Placebo-controlled study of quetiapine monotherapy in ambulatory bipolar spectrum disorder with moderate-to-severe hypomania or mild mania

BACKGROUND

There are no randomized, placebo-controlled data for quetiapine in outpatients with bipolar spectrum disorder (ambulatory BSD) and moderate-to-severe hypomanic or mild manic symptoms (hypomania/mild mania).

METHODS

An 8-week, randomized, double-blind, placebo-controlled trial of quetiapine in ambulatory BSD with hypomanic/mild manic symptoms, defined operationally as a score of >or=3 but <5 on the mania subscale of the Clinical Global Impressions Scale Modified for Bipolar Illness (CGI-BP) at baseline and one prior study visit, at least 3 days but no more than 2 weeks apart. The primary outcome measure was the rate of change in the Young Mania Rating Scale score (YMRS).

RESULTS

During the 8-week study period, patients receiving quetiapine (average daily dose=232mg) had a marginally greater rate of reduction in mean total YMRS score than patients receiving placebo (p=0.06). Additionally, CGI-BP mania (p=0.01) and the CGI-BP overall (p<0.001) scores were significantly reduced and the CGI-depression score (p=0.08) was marginally reduced in the quetiapine group. Six (32%) quetiapine patients and 8 (40%) placebo patients did not complete the trial.

LIMITATIONS

Small sample size and high attrition (36%).

CONCLUSION

Quetiapine was marginally more effective than placebo in reducing hypomanic/mild manic symptoms in ambulatory BSD as assessed by the YMRS. It was more effective than placebo in reducing manic symptoms and global bipolar symptoms as assessed by the CGI-BP. The drug's discontinuation rate was similar to placebo's. Controlled trials of quetiapine and other compounds with mood stabilizing properties in larger groups of ambulatory BSD patients with hypomanic/mild manic symptoms appear warranted.

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.

"Mixed hypomania" in children and adolescents: is it a pediatric bipolar phenotype with extreme diurnal variation between depression and hypomania?

BACKGROUND

Although DSM-IV and the literature on pediatric bipolarity recognize mania and mixed phases neither recognizes states of "mixed hypomania." There has been preliminary presentation of the latter phenomenon in the adult bipolar literature. The authors herein describe this phenomenon in a consecutive clinical series of bipolar children and adolescents.

METHODS

This exploratory study involved 47 consecutive bipolar patients between the ages of 7 and 17 years presenting to an outpatient clinic. They were evaluated using a structured instrument designed to ascertain the presence of major depressive episodes (MDE), hypomania, mania, psychotic disorders, behavioral disorders such as oppositional defiant disorder and conduct disorder and substance use disorders. We defined mixed hypomania as MDE and hypomania coexisting over at least 2 weeks.

RESULTS

Of 47 patients, 9 girls (42.9%) and 9 boys (34.6%) were bipolar II mixed. This paper focuses on them. The mean ages of the bipolar II girls and boys were 14.3 (1.9) years and 12.0 (3.4) years, respectively (p<0.05, t=2.45, df=17). This mixed subgroup tended to experience rising mood in the evening, often with spikes of euphoria; a history of late afternoon to evening increased talkativeness or pressured speech was common. Some patients exhibited flight of ideas. Psychomotor acceleration, heightened level of energy, and increased goal directed activity between 1900 and 0300 were frequently reported. Retrospectively obtained circadian information revealed, in most cases an age inappropriate phase delay of sleep onset: After falling asleep in the early hours of the morning the patients awoke feeling depressed, lethargic and as if they could sleep throughout much of the day.

LIMITATION

Cross-sectional, exploratory study based on a relatively small sample size and in need of replication in other clinical settings.

CONCLUSION

Mixed hypomania was a common phenomenon in pediatric bipolar II patients. It is apt to go unrecognized in cross-sectional assessments done in the morning or in the early or mid-afternoon. Those with this proposed phenotype would appear "depressed" at these times. Alternatively, what we have proposed can also be described as severe diurnal variation between depression and hypomania in the evening. Further study is required combining 24-hour clinical observation and state of the art technologically derived data.

Classifying mood disorders by age-at-onset instead of polarity

BACKGROUND

Polarity is the pillar of the current categorical unipolar-bipolar division of mood disorders. However, genetic studies on these polarity-based phenotypes have been largely inconclusive. Recent clinical and epidemiological studies seem to support more of a continuum than a splitting of mood disorders. A reshaping of the classification of mood disorders thus seems required. Age-at-onset and recurrence have been suggested to be more clinically and genetically useful in the phenotyping of mood disorders.

STUDY AIM

To test a classification of mood disorders based on age-at-onset, and to delineate its phenotypes.

METHODS

A total of 441 consecutive bipolar II disorder (BP-II) and 289 unipolar major depressive disorder (MDD) outpatients, presenting for treatment of a major depressive episode (MDE) in a clinical and research private practice, were assessed by a mood disorder specialist psychiatrist (FB) using a Structured Clinical Interview for the DSM-IV, modified for better probing past hypomania [Benazzi, F. Bipolar disorder-focus on bipolar II disorder and mixed depression. Lancet 2007a;369: 935-945]. The sample was divided according to age-at-onset. Age-at-onset was defined by the age at onset of the first MDE. Early-age-at-onset (EO) was defined as age at onset before 21 years, late-age-at-onset (LO) as onset at or after age 21 years. The study's current goal had not been planned when data were recorded between 1999 and 2006. Variables were compared in EO versus LO mood disorders, investigating phenotype differences. The main focus was on 'classic' diagnostic validators: MDE clinical picture, gender, course, and family history. Age, gender, BP-II, and mania/hypomania family history (possible confounding) were controlled for in the analyses. Logistic regression was used.

RESULTS

First, EO was regressed on each variable, one at a time, to find significant associations. Second, EO was regressed on all of the variables whose odds ratio (OR) was statistically significant in the previous analyses in order to find independent predictors. Independent predictors of EO mood disorder were history of hypomania, high recurrence, atypical depression, and family history of mania/hypomania. Controlling for BP-II (in addition to age and gender) did not impact the findings. The highest OR was that between EO and high recurrence (OR=4.00). Distinguishing MDE symptoms of EO mood disorder included hypersomnia and psychomotor agitation when controlling for age and gender, and, by controlling also for BP-II, hypersomnia only.

DISCUSSION

A close association among EO mood disorder, high recurrence, and bipolarity (history of hypomania, family history of mania/hypomania) was found. Compared to most previous studies testing EO versus LO in bipolar (mainly BP-I) or in unipolar MDD samples, the present study tested a mixed BP-II and MDD sample and controlled for polarity, reducing, as much as possible, the impact of polarity on the findings. EO (below age 21 years) was distinguished by hypersomnic depression, high recurrence, high history of hypomania, and high history of mania/hypomania. Replications are needed, especially in mixed samples also including BP-I. Results, if replicated, could have implications not only for clinical and genetic studies, but also for treatment (e.g., mood stabilizers could have better long-term effects than antidepressants in EO mood disorders, antidepressants could have negative long-term effects on EO).

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.

Defining mixed depression

BACKGROUND

Mixed depression, i.e. a major depressive episode plus co-occurring manic/hypomanic symptoms, has recently become the focus of research. However, it is still unclear if its definition should be based on specific manic symptoms or on a number/score of manic symptoms. Different definitions may have different diagnostic utility, such as treatment impacts.

STUDY AIM

Study aim was to test which definition of mixed depression was more supported, by using, as diagnostic validator, early age at onset on the basis of previous studies supporting its bipolar nature.

METHODS

Consecutive 336 Bipolar II Disorder (BP-II), and 224 Major Depressive Disorder (MDD) outpatients were cross-sectionally assessed for major depressive episode (MDE) and concurrent DSM-IV hypomanic symptoms when presenting for treatment of depression, by a mood disorder specialist psychiatrist using the Structured Clinical Interview for DSM-IV as modified by Akiskal and Benazzi (J Clin Psychiatry, 2005) and the Hypomania Interview Guide (HIG), in a private practice. Mixed depression was defined as co-occurrence of MDE and hypomanic symptoms. Early age at onset (EO) below 21 years was used as diagnostic validator.

RESULTS

Multivariable logistic regression of EO versus all within-MDE hypomanic symptoms, controlled for BP-II, showed that no specific symptom was independently associated with EO. By ROC analysis versus EO, the best combination of sensitivity and specificity, and the highest figure of correctly classified, were shown by a cutoff number >=3 symptoms, and by a cutoff HIG score >=8. Both cutoffs had similar strength of association with EO. Mixed depression defined by >=3 within-MDE hypomanic symptoms (A), or by a HIG score >=8 (B), were more frequent in EO group versus LO group (A: 70.5% versus 49.8%; B: 60.7% versus 40.9%; p<0.001), and in BP-II versus MDD (A: 72.3% versus 39.7%; p<0.001; positive predictive value for BP-II=73.1%; B: 63.9% versus 29.0%; p<0.001; positive predictive value for BP-II=76.7%).

DISCUSSION

Findings could support the diagnostic validity of a definition of mixed depression based on a cutoff number/score of within-depression hypomanic symptoms versus one based on specific symptoms, complementing and supporting previous studies using bipolar family history as validator. Diagnosing mixed depression has treatment impacts, such as careful use of antidepressants added to mood stabilising agents or no use of antidepressants, as recently shown by large naturalistic and controlled studies.

A relationship between bipolar II disorder and borderline personality disorder?

BACKGROUND

The relationship between DSM-IV-TR borderline personality disorder (BPD) and bipolar disorders, especially bipolar II disorder (BP-II), is still unclear. Many recent reviews on this topic have come to opposite or different conclusions.

STUDY AIM

The aim was to test the association between hypomania symptoms and BPD traits, as hypomania is the defining feature of BP-II in DSM-IV-TR.

METHODS

During follow-up visits in a private practice, consecutive 138 remitted BP-II outpatients were re-diagnosed by a mood disorder specialist psychiatrist, using the Structured Clinical Interview for DSM-IV (as modified by Benazzi and Akiskal for better probing hypomania). Soon after, patients self-assessed (blind to interviewer) the SCID-II Personality Questionnaire for BPD. Associations and confounding were tested by logistic regression, between each criteria symptom of hypomania (apart from "racing thoughts" and "distractibility", not assessed as probing focused mainly on behavioral, observable signs), and the entire set of BPD traits. Multivariate regression was also used to jointly regress the entire set of hypomanic symptoms on the entire set of BPD traits.

RESULTS

Mean (SD) age was 39.0 (9.8) years, females were 76.3%. Frequency of BPD traits ranged between 17% and 66% (e.g. impulsivity trait 41%, affective instability trait 63%), mean (SD) number of traits was 4.2 (2.3). The most common episodic hypomanic symptoms were elevated mood (91%) and overactivity (93%); frequency of excessive risky, impulsive activities (impulsivity) was 62%. By logistic regression the only significant association was between the episodic impulsivity of hypomania and the trait impulsivity of BPD. Multivariate regression of the entire set of hypomanic symptoms jointly regressed on the entire set of BPD traits was not statistically significant.

DISCUSSION

The core feature of BP-II, i.e. hypomania, does not seem to have a close relationship with BDP traits in the study setting, partly running against a strong association between BPD and BP-II and a bipolar spectrum nature of BPD.

A tetrachoric factor analysis validation of mixed depression

BACKGROUND

Mixed depression, i.e. a Major Depressive Episode plus co-occurring manic/hypomanic symptoms, has recently become the focus of research. However, its diagnostic validity and bipolar nature are still not firmly supported. A bipolar nature could have significant treatment impacts.

STUDY AIM

The aim was to psychometrically validate the concept of, and the bipolar nature, of mixed depression, by using (for the first time) tetrachoric factor analysis of its hypomanic symptoms.

METHODS

Consecutive 441 Bipolar II Disorder (BP-II), and 289 Major Depressive Disorder (MDD) outpatients were cross-sectionally assessed for Major Depressive Episode (MDE) and concurrent hypomanic symptoms (as binary variables) when presenting for treatment of depression, by a mood disorder specialist psychiatrist (FB), using the Structured Clinical Interview for DSM-IV (as modified by [Akiskal HS, Benazzi F. Optimizing the detection of bipolar II disorder in outpatient private practice: toward a systematization of clinical diagnostic wisdom. J Clin Psychiatry 2005; 66: 914-921.]) in a private practice. Consecutive 275 remitted BP-II were also assessed for past hypomania. Mixed depression was defined as co-occurrence of MDE and 3 or more, usually subthreshold, hypomanic symptoms.

RESULTS

In multivariable logistic regression, BP-II independent predictor variables were young onset age, MDE recurrences, mixed depression, and bipolar family history. Factor analysis of past hypomania symptoms found three factors: an "irritable mental overactivity" factor, an "elevated mood" factor, and a "motor overactivity" factor. Factor analysis of intradepression hypomanic symptoms in BP-II, and in MDD, found two similar mental and motor overactivity factors. Multivariate regression of the intradepression hypomanic factors versus bipolar validators, such as bipolar family history and young onset age, found significant associations.

DISCUSSION

Findings could support the diagnostic validity, and the bipolar nature, of mixed depression, on the basis of the close similarities found between the factor structure of inter-depression hypomania and intra-depression hypomanic symptoms. Impacts on treatment of a bipolar nature of mixed depression may be significant (e.g. more use of mood stabilising agents, less/no use of antidepressants).