Mixed features: evolution of the concept, past and current definitions, and future prospects

Validity of the DSM-5 Mixed Features Specifier Interview

OBJECTIVES

To examine the reliability and validity of a semi-structured interview assessing the features of the DSM-5 mixed features specifier. Our goal was to develop an instrument that could be used for both diagnostic and severity measurement purposes.

METHODS

Four hundred fifty-nine psychiatric patients in a depressive episode were interviewed by a trained diagnostic rater who administered semi-structured interviews including the DSM-5 Mixed Features Specifier Interview (DMSI). We examined the inter-rater reliability and psychometric properties of the DMSI. The patients were rated on clinician rating scales of depression, anxiety, and irritability, and measures of psychosocial functioning, suicidality, and family history of bipolar disorder.

RESULTS

The DMSI had excellent joint-interview interrater reliability. More than twice as many patients met the DSM-5 mixed features specifier criteria during the week before the assessment than for the majority of the episode (9.4% vs. 3.9%). DMSI total scores were more highly correlated with a clinician-rated measure of manic symptoms than with measures of depression and anxiety. More patients with bipolar depression met the mixed features specifier than patients with MDD. Amongst patients with MDD, those with mixed features more frequently had a family history of bipolar disorder, were more frequently diagnosed with anxiety disorders, attention deficit disorder, and borderline personality disorder, more frequently had attempted suicide, and were more severely depressed, anxious, and irritable.

CONCLUSION

The DMSI is a reliable and valid measure of the presence of the DSM-5 mixed features specifier in depressed patients as well as the severity of the features of the specifier.

Examining the Relationships between the Incidence of Infectious Diseases and Mood Disorders: An Analysis of Data from the Global Burden of Disease Studies, 1990-2019

Mood disorders are among the commonest mental disorders worldwide. Epidemiological and clinical evidence suggests that there are close links between infectious diseases and mood disorders, but the strength and direction of these association remain largely unknown. Theoretical models have attempted to explain this link based on evolutionary or immune-related factors, but these have not been empirically verified. The current study examined cross-sectional and longitudinal associations between the incidence of infectious diseases and mood disorders, while correcting for climate and economic factors, based on data from the Global Burden of Disease Studies, 1990-2019. It was found that major depressive disorder was positively associated with lower respiratory infections, while bipolar disorder was positively associated with upper respiratory infections and negatively associated with enteric and tropical infections, both cross-sectionally and over a period of 30 years. These results suggest that a complex, bidirectional relationship exists between these disorders. This relationship may be mediated through the immune system as well as through the gut-brain and lung-brain axes. Understanding the mechanisms that link these groups of disorders could lead to advances in the prevention and treatment of both.

Clinical research diagnostic criteria for bipolar illness (CRDC-BP): rationale and validity

BACKGROUND

In the 1970 s, scientific research on psychiatric nosology was summarized in Research Diagnostic Criteria (RDC), based solely on empirical data, an important source for the third revision of the official nomenclature of the American Psychiatric Association in 1980, the Diagnostic and Statistical Manual, Third Edition (DSM-III). The intervening years, especially with the fourth edition in 1994, saw a shift to a more overtly "pragmatic" approach to diagnostic definitions, which were constructed for many purposes, with research evidence being only one consideration. The latest editions have been criticized as failing to be useful for research. Biological and clinical research rests on the validity of diagnostic definitions that are supported by firm empirical foundations, but critics note that DSM criteria have failed to prioritize research data in favor of "pragmatic" considerations.

RESULTS

Based on prior work of the International Society for Bipolar Diagnostic Guidelines Task Force, we propose here Clinical Research Diagnostic Criteria for Bipolar Illness (CRDC-BP) for use in research studies, with the hope that these criteria may lead to further refinement of diagnostic definitions for other major mental illnesses in the future. New proposals are provided for mixed states, mood temperaments, and duration of episodes.

CONCLUSIONS

A new CRDC could provide guidance toward an empirically-based, scientific psychiatric nosology, and provide an alternative clinical diagnostic approach to the DSM system.

Undetermined predominant polarity in a cohort of bipolar disorder patients: Prevalent, severe, and overlooked

OBJECTIVES

Predominant polarity (PP) is a concept used to define patients with bipolar disorder (BD) as presenting a tendency to manifest depressive (DPP) or manic (MPP) episodes. Still, the high percentage of patients with an undetermined PP (UPP), has been overlooked in most studies. Thus, we aimed to study UPP and outline its socio-demographic, clinical, and treatment-related features.

METHODS

Patients were recruited from a BD specialized unit. The sample was divided into three groups according to PP and socio-demographic and clinical variables were compared. Significant variables at univariate comparisons were included in multivariate logistic regression with UPP as the dependent variable.

RESULTS

A total of 708 BD patients were included, of which 437 with UPP (61.7%). UPP was associated with a higher number of affective relapses, when compared with DPP or MPP (χ2= 28.704, p<0.001). Mixed episodes (OR=1.398; CI=1.118-1.749), aggressive behaviour (OR=1.861; CI=1.190-2.913), seasonality (OR=2.025; CI= 1.289-3.501) and treatment with lamotrigine (OR= 2.101; CI=1.244-3.550) were significantly associated with UPP at the logistic regression.

LIMITATIONS

Recall bias may have occurred due to mixed episode diagnostic criteria change over the years. No data on the patients' follow-up has been reported on predominant polarity changes.

CONCLUSIONS

UPP is associated with a higher number of relapses, and different clinical variables related to a severe course of illness. Considering PP in patients with BD may guide the choice for differential treatment approaches having an impact on BD course of illness and patients' prognosis and recovery.

Pattern of occurrence of obsessive-compulsive symptoms in bipolar disorder

Apparent comorbidity between Bipolar Disorder (BD) and Obsessive-Compulsive Disorder (OCD) is a common condition, but its meaning has not been clarified yet. The present study aimed to evaluate the pattern of occurrence of obsessive-compulsive symptoms (OCS) in the different phases of BD. One hundred and sixty-five BD patients, 62 (37.5%) euthymic, 34 (20.6%) in hypomanic/manic phase, 43 (26%) in depressive phase and 26 (15.7%) in mixed state, were assessed with the Yale-Brown Obsessive-Compulsive Scale (YBOCS), the Hamilton Depression Rating Scale (HAM-D), the Young Mania Rating Scale (YMRS) and the Ruminative Response Scale (RRS). In the whole sample, the severity of OCS was associated to the severity of depressive symptoms. The highest severity of OCS (YBOCS total score) was observed in the mixed group and the lowest scores in the hypomanic/manic group. Our findings suggest that OCS in BD patients appear as a state-dependent phenomenon cycling with the mood phases, particularly exacerbating in the context of depressive and mixed states.

Dissociative Symptoms in Bipolar Disorder: Impact on Clinical Course and Treatment Response

Background: Dissociative symptoms are under recognized and scarcely studied by clinicians and researchers in patients with bipolar disorder (BD). We examined the relationship between dissociative symptoms and the psychotic features in patients with BD and assessed clinical and socio-demographic characteristics more frequently associated with dissociative symptoms and treatment response. Methods: Participants were 100 adult outpatients with BD. They were screened with semi-structured interview to collect socio-demographic and clinical characteristics; the Dissociative Experiences Scale-II (DES-II) and the ALDA scale were used to assess dissociative psychopathologies and response to treatment with mood stabilizers, respectively. Results: DES score (mean 31.7 ± 21.7) correlated with clinical variables, BD features, and course of illness. Psychotic symptoms, mixed features, and previous suicide attempts significantly predicted DES score [F _{(3, 47)} = 39.880, p < 0.001, R ² corrected = 0.713]. Dissociative symptoms were inversely correlated with poor response to treatment (r = -0.593; p < 0.001). Limitations: Cross-sectional design with a small sample and backward clinical assessment of psychotic symptoms. Conclusions: Dissociative phenomena are closely related to the presence of psychotic symptoms, mixed features, and previous suicide attempts in BD, especially in BD-I. Given the close association between dissociative and psychotic symptoms, this association could represent a diagnostic indicator of BD-I that may guide the clinician to plan the most appropriate treatment.

The 12-Item Self-Rating Questionnaire for Depressive Mixed State (DMX-12) for Screening of Mixed Depression and Mixed Features

For simultaneous screening of mixed features (MF) by DSM-5 and mixed depression (MD) by Benazzi, useful symptoms were extracted from our 12-item dimensional scale for depressive mixed state (DMX-12). Subjects were 190 consecutive cases with major depressive episode (MDE) who visited our clinic. Associations between symptomatological combinations of the DMX-12 and MF or MD were analyzed using receiver operating characteristic (ROC). The rate of MF was 4.2% while that of MD was 22.6%. Eight symptoms (overreactivity, inner tension, racing/crowded thought, impulsivity, irritability, aggression, risk-taking behavior, and dysphoria) with their AUC > 0.6 for ROC curves were specially focused on distinguishing patients with MF or MD from non-mixed patients. By using these 8 symptoms, 40.5% of the overall patients were screened as positive at the same cut-off value (≥13) for both MD and MF. The AUC of ROC curve and sensitivity/specificity were well balanced together with sufficient negative predictive values. The abovementioned 8 symptoms seem to be helpful for primary screening and negative check of DMX with considerable severity during MDE.

Homocysteine, chronotype and clinical course in bipolar disorder patients

Purpose: Higher homocysteine (HHcy) levels have been detected in bipolar disorder (BD) patients, and BD patients show circadian rhythm disorders even during remission. Here, we determined the homocysteine (Hcy) levels and chronotype of patients with BD during remission and investigated whether this was related to the clinical course of the disease. Materials and methods: In total, 80 BD outpatients were included. Clinical evaluation was conducted using the Hamilton Depression Rating Scale (HDRS), Young Mania Rating Scale (YMRS), Pittsburgh Sleep Quality Index (PSQI) and the Morningness-Eveningness Questionnaire (MEQ). Hcy, folic acid, vitamin B12 levels and protein consumption the day before clinical evaluation were measured.Results and conclusions: HHcy was found in 11 patients (8.8%), most of whom were males (n = 8, 72.7%). During the course of BD, patients with HHcy had significantly more mixed episodes than patients without HHcy (p = .007, z = -2696). In addition, patients with HHcy had significantly lower MEQ scores than patients without HHcy (p = .04, t = 2018). There was no significant difference in chronotype between patients with and without HHcy. The HHcy group had significantly lower levels of vitamin B12 (p = .003, t = 2870). There were no statistically significant differences in daily protein intake and folic acid levels between HHcy and non-HHcy groups. Our study showed a significant relationship between the number of mixed episodes and HHcy. In terms of potential confounds, patients who abused alcohol were excluded, but alcohol consumption was not evaluated. This result should be considered in BD and should be evaluated in larger samples of BD patients.

Temporal Structure of Mixed States: Does Sensitization Link Life Course to Episodes?

Susceptibility to combined depressive and manic syndromes correlates strongly with arousal-related symptoms including impulsivity, anxiety and agitation. This relationship to a driven, "mixed" activation-depression state, generated by a life-long process, was described in classical times. Course of illness in mixed states includes increased episode frequency, duration, earlier onset, and association with addiction- and trauma/stress-related disorders. Mixed episodes have catecholamine and hypothalamic-pituitary-adrenocortical activity increased beyond nonmixed states of similar symptom severity. These properties resemble behavioral sensitization, where salient, survival-related stimuli (traumatic or rewarding) can generate persistently exaggerated responses with disrupted arousal and reward, with potential for suicide and other severe consequences.

Mixed States: Historical Impact and Evolution of the Concept

Mixed states have been discussed for more than 2 millennia. The theoretic conception of the coexistence of presumably opposite symptoms of mood or of different psychic domains is well established, although obscured by the presumed separation between bipolar and depressive disorders. Moreover, the lack of response to treatments and severe psychopathology raise important issues requiring urgent solution. The aim of this article was to review the development of the concept of mixed states from the classic literature to modern nosologic systems and to claim for the need of a new paradigm to address the still-open issues about mixed states.

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.

Chris Cornell, the Black Hole Sun, and the Seasonality of Suicide

PURPOSE

Seattle-inspired rock and roll superstar Chris Cornell died by suicide in May 2017. In the northern hemisphere, May represents the peak of the widely replicated but still unexplained seasonal spring rhythm in suicide. Years earlier, Cornell had suffered openly from recurrent bouts of severe depression, and his early musical lyrics do indeed suggest an enduring sensitivity to the vicissitudes of depressed and suicidal states. Cornell's most famous song, Black Hole Sun, suggests a mixed mood state, the incidence of which also peaks in the spring. The present work explores Cornell's May suicide from a chronobiologic perspective.

METHODS

Review of Cornell's lyrics and literature on suicide.

RESULTS

Cornell's lyrics contain clear indicators of mixed depressive and seasonal imagery, highlighting 3 fundamental axioms of suicidology: (1) the yearly suicide rhythm peaks in May in the northern hemisphere, (2) mixed depressive states are particularly lethal, and (3) the suicide risk increases dramatically when recovering from depression and mood turns mixed.

CONCLUSIONS

Cornell, in his life and music, left us with a novel and important hypothesis about the spring seasonality of suicide, namely, that the yearly suicide risk becomes maximal when winter turns to spring and there emerges a deadly mixed mood state under a May photoperiod, i.e., the suicide risk is maximal when a Black Hole Sun occurs in May. It is hoped that Cornell's legacy and sensitive hypothesis inspire research into the etiology and treatment of the spring seasonality of suicide risk and mixed mood states.

LIMITATIONS

The Cornell hypothesis was formulated based in part on several speculative inferences regarding the course of his functioning just prior to his suicide.

Development of the 12-item questionnaire for quantitative assessment of depressive mixed state (DMX-12)

BACKGROUND

Conventional categorical criteria have limitations in assessing the prevalence and severity of depressive mixed state (DMX). Thus, we have developed a new scale for screening and quantification of DMX and examined the symptomatological structure and severity of DMX in individuals with major depressive episode (MDE).

METHODS

Subjects were 154 patients with MDE (57 males and 97 females; age 13-83 years). Our original Japanese version of the self-administered 12-item questionnaire to assess DMX (DMX-12), together with the Quick Inventory of Depressive Symptomatology Self-Report Japanese version (QIDS-SR-J) and global assessment of functioning, were administered to each participant. The symptomatological structure of the DMX-12 was examined by exploratory factor analysis. Multiple regression analyses were used to analyze factors contributing to the DMX-12 scale. The relationships of this scale with categorical diagnoses (mixed depression by Benazzi and mixed features by DSM-5) were also investigated.

RESULTS

A three-factor model of the DMX-12 was extracted from exploratory factor analysis, namely, "spontaneous instability", "vulnerable responsiveness", and "disruptive emotion/behavior". Multiple regression analyses revealed that age was negatively correlated with total DMX-12 score, while bipolarity and the QIDS-SR-J score were positively correlated. A higher score on the disruptive emotion/behavior subscale was observed in patients with mixed depression and mixed features.

CONCLUSION

The DMX-12 seems to be useful for screening DMX in conjunction with conventional categorical diagnoses. Severely depressed younger subjects with potential bipolarity are more likely to develop DMX. The disruptive emotion/behavior subscale of the DMX-12 may be the most helpful in distinguishing patients with DMX from non-mixed patients.

Is suicide risk a predictor of diagnosis conversion to bipolar disorder?

To assess predictors of the diagnosis of bipolar disorder is important since it is known that the early diagnosis is associated with a better response to the treatment. Thus, the aim of this systematic review is to assess the role of the suicide risk in the diagnosis conversion to bipolar disorder. We searched Pubmed, Bireme, Scopus, and PsycINFO with no year restriction for articles containing the words (suicidal or suicide or suicide risk or suicide attempt) and (conversion or switch) and (bipolar disorder or mania or hypomania or bipolar disorders). The review included four studies, with only one confirming that subjects who converted to bipolar disorder had higher rates of suicide risk than subjects who did not convert to bipolar disorder. The main limitation of this review is that few longitudinal studies assessed the predictors of conversion to bipolar disorders. In conclusion, suicide risk appears to be a predictor of bipolar disorder; nevertheless, more studies are needed to confirm this association.

Mixed states in bipolar and major depressive disorders: systematic review and quality appraisal of guidelines

OBJECTIVE

This systematic review provided a critical synthesis and a comprehensive overview of guidelines on the treatment of mixed states.

METHOD

The MEDLINE/PubMed and EMBASE databases were systematically searched from inception to March 21st, 2018. International guidelines covering the treatment of mixed episodes, manic/hypomanic, or depressive episodes with mixed features were considered for inclusion. A methodological quality assessment was conducted with the Appraisal of Guidelines for Research and Evaluation-AGREE II.

RESULTS

The final selection yielded six articles. Despite their heterogeneity, all guidelines agreed in interrupting an antidepressant monotherapy or adding mood-stabilizing medications. Olanzapine seemed to have the best evidence for acute mixed hypo/manic/depressive states and maintenance treatment. Aripiprazole and paliperidone were possible alternatives for acute hypo/manic mixed states. Lurasidone and ziprasidone were useful in acute mixed depression. Valproate was recommended for the prevention of new mixed episodes while lithium and quetiapine in preventing affective episodes of all polarities. Clozapine and electroconvulsive therapy were effective in refractory mixed episodes. The AGREE II overall assessment rate ranged between 42% and 92%, indicating different quality level of included guidelines.

CONCLUSION

The unmet needs for the mixed symptoms treatment were associated with diagnostic issues and limitations of previous research, particularly for maintenance treatment.

Characteristics of depressive and bipolar disorder patients with mixed features

OBJECTIVE

To assess differences between subjects with vs. without mixed features in major affective disorders.

METHODS

In 3099 out-patient subjects with DSM-5 major depressive disorder (MDD, n = 1921) or bipolar disorders (BD, n = 1178), we compared those with (Mx) vs. without (Non-Mx) mixed features (agitated-irritable depression or dysphoric [hypo]mania) in an index episode.

RESULTS

Prevalence of Mx averaged 21.9% [CI: 20.5-23.4] overall, ranking: BD-II > BD-I > MDD, and in BD depression ≥ [hypo]mania > MDD. Mx subjects were significantly more likely than Non-Mx cases to (i) have other mixed episodes, (ii) have higher irritable and agitated ratings, (iii) have more substance abuse, (iv) switch into mixed episodes, (v) have more suicide attempts and higher suicidal ratings, (vi) change diagnosis from depression to BD, (vii) have higher hypomania scores when depressed or depression scores when [hypo]manic, (viii) be unmarried or separated with fewer children and siblings, (ix) be diagnosed more with BD than MDD, (x) be unemployed, (xi) have BD, suicide and divorce among first-degree relatives, (xii) be female, (xiii) be younger at illness-onset. Both BD and MDD Mx subjects also received antidepressants less, but antipsychotics and mood-stabilizers more, alone and in combination with antidepressants.

CONCLUSIONS

Mood disorder subjects with agitated-irritable depression or dysphoric [hypo]mania differed from those without such mixed features, including having a less favorable clinical course and repeated mixed episodes. They may represent a distinct and prevalent, syndromal clinical subtype with prognostic and therapeutic significance.