A prospective study of inter-episode consistency of manic and mixed subtypes of bipolar disorder

The CANMAT and ISBD Guidelines for the Treatment of Bipolar Disorder: Summary and a 2023 Update of Evidence

Bipolar disorder is a complex and heterogeneous psychiatric condition that affects more than 2% of the population. The assessment and treatment of bipolar disorder can be a challenge for clinicians, given its clinical complexity and the rapidly changing treatment landscape with the growing range of treatment options that are becoming available for various phases of the illness. To help clinicians navigate the complexity involved in the assessment and management of bipolar disorder, the guidelines of the 2018 Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) synthesized the evidence on the efficacy, safety, and tolerability of treatments for bipolar disorder and translated it into first-, second-, and third-line treatment recommendations. The main objective of this contribution is to provide clinicians with a summary of the 2018 CANMAT/ISBD guideline recommendations with the addition of any new evidence for the treatment of bipolar disorder across the lifespan.

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.

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.

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.

Mixed states in bipolar disorder - changes in DSM-5 and current treatment recommendations

OBJECTIVE

Mixed states in affective disorders represent a particular challenge in clinical routine, characterized by a complicated course of treatment and a worse treatment response.

METHODS

Clinical features of mixed states and the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria are presented and critical discussed. We then performed a systematic review using the terms 'bipolar', 'mixed' and 'randomized' to evaluate current treatment options.

RESULTS

For pharmacological treatment of mixed states in total, there is still insufficient data from RCTs. However, there is some evidence for efficacy in mixed states from RCTs for atypical antipsychotics, especially olanzapine, aripiprazole and asenapine as well as mood stabilizers as valproate and carbamazepine.

CONCLUSIONS

Mixed states are of a high clinical relevance and the DSM-5 criteria substantially reduced the diagnostic threshold. Besides advantages of a better characterization of patients with former DSM-IV-defined mixed episodes, disadvantages arise for example differential diagnoses with a substantial overlap in symptoms such as borderline personality disorders. Atypical antipsychotics, valproate and carbamazepine demonstrated efficacy in a limited sample of RCTs.

LIMITATIONS

The number of RCTs in the treatment of mixed states is highly limited. Furthermore, nearly all studies were funded by pharmaceutical companies which may lead to an underestimation of classical mood stabilizers such as lithium.

The significance of mixed states in depression and mania

The DSM-5 definition of mixed features "specifier" of manic, hypomanic and major depressive episodes captures sub-syndromal non-overlapping symptoms of the opposite pole, experienced in bipolar (I, II, and not otherwise specified) and major depressive disorders. This combinatory model seems to be more appropriate for less severe forms of mixed state, in which mood symptoms are prominent and clearly identifiable. Sub-syndromal depressive symptoms have been frequently reported to co-occur during mania. Similarly, manic or hypomanic symptoms during depression resulted common, dimensionally distributed, and recurrent. The presence of mixed features has been associated with a worse clinical course and high rates of comorbidities including anxiety, personality, alcohol and substance use disorders and head trauma or other neurological problems. Finally, mixed states represent a major therapeutic challenge, especially when you consider that these forms tend to have a less favorable response to drug treatments and require a more complex approach than non-mixed forms.

Role of substance abuse comorbidity and personality on the outcome of depression in bipolar disorder: harm avoidance influences medium-term treatment outcome

Comorbid conditions are frequent in bipolar disorder (BD) and may complicate the treatment and course of illness. We investigated the role of substance use disorder (SUD), axis II personality disorders (PD) and continuous personality traits on the medium-term outcome (6 months) of treatment for bipolar depression. One hundred and thirty-nine BD patients meeting criteria for a depressive episode were included in the study. SUD and PD were diagnosed according to structured interviews. Personality dimensions were evaluated by the Temperament and Character Inventory. Depressive severity over time was evaluated by the Hamilton Rating Scale for Depression. Neither PD nor SUD influenced the outcome of depression. Variables independently associated with a poor outcome were a high baseline severity and high scores for the temperamental trait of Harm Avoidance. Though several limitations characterize the present study, neurotic personality traits seem to be associated with a slower recovery from depressive symptoms in BD, independently from their initial severity.

Association between median family income and self-reported mood symptoms in bipolar disorder

OBJECTIVE

There is broad consensus from epidemiologic research that lower socioeconomic status is related to poorer health. This study investigated the relation between median family income and self-reported mood symptoms in patients with bipolar disorder who reside in the United States.

METHODS

Two hundred eighty-four patients with bipolar disorder provided daily self-reported mood ratings for 6 months (50,054 days of data). Regardless of income, all patients were treated by a psychiatrist, took psychotropic medications, and participated in computerized self-monitoring throughout the study. Median family income was obtained from US census tract data. The association between income and mood was analyzed using income as both a continuous and categorical variable. Demographic characteristics were compared by income group. Education level was included in the analysis a priori.

RESULTS

Both the continuous and categorical approaches found a positive association between income and euthymia, a negative association between income and manic/hypomanic symptoms including those due to mixed states, and no association between income and depressive symptoms. Patients in the lower-income group spent 12.4% fewer days euthymic than those in the upper-income group and 9.7% fewer days euthymic than those in the middle-income group. Patients in the lower-income group spent 7.1% more days with manic/hypomanic symptoms than those in the upper-income group. There was no association between education and income.

CONCLUSION

Median family income is associated with mood symptoms in patients with bipolar disorder. Inclusion of income as a measure of socioeconomic status is recommended for future studies of outcome in bipolar disorder.

Insight in bipolar disorder: relationship to episode subtypes and symptom dimensions

BACKGROUND

The study of insight in bipolar disorder has received limited attention, despite its potential impact on treatment compliance and prognosis. In the current study we compare insight levels during different phases of bipolar disorder, and consider its relationship to symptoms dimensions and epidemiologic variables.

METHODS

Insight ratings obtained from 156 bipolar subjects in any phase of bipolar disorder were compared. A regression analysis was also conducted to identify symptom dimensions predictive of insight levels.

RESULTS

Greater impairments in insight were observed during pure manic episodes than during mixed or depressed episodes, or during euthymia. Depressive symptoms were associated with better insight. Improvements in insight with treatment were neither complete nor universal. Lack of insight was unrelated to age, years of illness, age of first psychiatric illness, or lifetime number of hospitalizations.

CONCLUSIONS

Although psychosis may be associated with impaired insight, other variables also impact on degree of impaired insight. Specifically, depressed mood appears to be associated with preservation of insight. That relationship may transcend strict syndromal diagnosis.

Continuum of depressive and manic mixed states in patients with bipolar disorder: quantitative measurement and clinical features

Bipolar mixed states combine depressive and manic features, presenting diagnostic and treatment challenges and reflecting a severe form of the illness. DSM-IV criteria for a mixed state require combined depressive and manic syndromes, but a range of mixed states has been described clinically. A unified definition of mixed states would be valuable in understanding their diagnosis, mechanism and treatment implications. We investigated the manner in which depressive and manic features combine to produce a continuum of mixed states. In 88 subjects with bipolar disorder (DSM-IV), we evaluated symptoms and clinical characteristics, and compared depression-based, mania-based, and other published definitions of mixed states. We developed an index of the extent to which symptoms were mixed (Mixed State Index, MSI) and characterized its relationship to clinical state. Predominately manic and depressive mixed states using criteria from recent literature, as well as Kraepelinian mixed states, had similar symptoms and MSI scores. Anxiety correlated significantly with depression scores in manic subjects and with mania scores in depressed subjects. Discriminant function analysis associated mixed states with symptoms of hyperactivity and negative cognitions, but not subjective depressive or elevated mood. High MSI scores were associated with severe course of illness. For depressive or manic episodes, characteristics of mixed states emerged with two symptoms of the opposite polarity. This was a cross-sectional study. Mixed states appear to be a continuum. An index of the degree to which depressive and manic symptoms combine appears useful in identifying and characterizing mixed states. We propose a depressive or manic episode with three or more symptoms of the opposite polarity as a parsimonious definition of a mixed state.

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.

Manic symptoms and impulsivity during bipolar depressive episodes

OBJECTIVES

In contrast to the extensive literature on the frequent occurrence of depressive symptoms in manic patients, there is little information about manic symptoms in bipolar depressions. Impulsivity is a prominent component of the manic syndrome, so manic features during depressive syndromes may be associated with impulsivity and its consequences, including increased risk of substance abuse and suicidal behavior. Therefore, we investigated the prevalence of manic symptoms and their relationships to impulsivity and clinical characteristics in patients with bipolar depressive episodes.

METHODS

In 56 bipolar I or II depressed subjects, we investigated the presence of manic symptoms, using Mania Rating Scale (MRS) scores from the Schedule for Affective Disorders and Schizophrenia (SADS), and examined its association with other psychiatric symptoms (depression, anxiety, and psychosis), age of onset, history of alcohol and/or other substance abuse and of suicidal behavior, and measures of impulsivity.

RESULTS

MRS ranged from 0 to 29 (25th-75th percentile, range 4-13), and correlated significantly with anxiety and psychosis, but not with depression, suggesting the superimposition of a separate psychopathological mechanism. Impulsivity and history of substance abuse, head trauma, or suicide attempt increased with increasing MRS. Receiver-operating curve analysis showed that MRS could divide patients into two groups based on history of alcohol abuse and suicide attempt, with an inflection point corresponding to an MRS score of 6.

DISCUSSION

Even modest manic symptoms during bipolar depressive episodes were associated with greater impulsivity, and with histories of alcohol abuse and suicide attempts. Manic symptoms during depressive episodes suggest the presence of a potentially dangerous combination of depression and impulsivity.

Bipolar II and the bipolar spectrum

In studies made in the last decade, patients consulting doctors because of depression and anxiety have very often turned out to suffer from bipolar type II and similar conditions with alternating depression and hypomania/mania (the bipolar spectrum disorders - BP). Specifically, about every second patient seeking consultation because of depression has been shown to suffer from BP, mainly bipolar type II. BP is often concealed by other psychiatric conditions, e.g. recurrent depression, psychosis, anxiety, addiction, personality disorder, attention-deficit hyperactivity disorder and eating disorder. BP shows strong heredity. Relatives of patients with BP also have a high frequency of the psychiatric conditions just mentioned. Conversion ("switching") from recurrent unipolar depressions (recurrent UP) to BP is common in very long longitudinal studies (over decades). Mood-stabilizing medicines are recommended to a great extent in the treatment of BP, since anti-depressive medicines are often not effective and involve a substantial risk of inducing mood swings. Particularly in the long-term pharmacological treatment of depression in BP anti-depressive medicines may worsen the condition, e.g. inducing a symptom triad of dysphoria, irritability and insomnia: ACID (antidepressant-associated chronic irritable dysphoria).

Toward a clinical delineation of dysphoric hypomania - operational and conceptual dilemmas

OBJECTIVE

Unlike dysphoric mania, we are unaware of any formal studies of dysphoric hypomania (DH). For this reason, DH is not formally recognized by DSM-IV and ICD-10. Analogous to the DSM-IV approach in the diagnosis of manic mixed state, in this exploratory study we operationalized DH as coexisting full syndromal hypomanic and major depressive states.

METHODS

In an Italian outpatient private practice setting, 320 BP-II outpatients [meeting DSM-IV criteria except for shorter (> or =2 days) floor duration for history of hypomanic episodes] were further interviewed with the modified SCID-CV for the simultaneous presence of hypomanic and depressive signs and symptoms during the index presenting affective episode or its exacerbation. Hypomania always included irritable mood plus at least four hypomanic signs and symptoms. Such non-euphoric hypomania had to last at least 1 week.

RESULTS

Only 45 (14.0%) met our proposed criteria for DH. Less stringently defined depressive mixed states (DMX) were excluded from further analyses. When compared with 120 of the 320 (37.5%) 'pure' BP-II (i.e., not meeting mixed state criteria), DH emerged as an irritable affective state, demonstrated a significantly higher rate of females, mood lability, racing/crowded thoughts, distractibility, increased talkativeness, psychomotor agitation, and increased goal-directed drives. Psychomotor agitation/activation had a specificity of 87% and sensitivity of 94%, correctly classifying 92% of cases of DH.

CONCLUSIONS

The DSM-IV concept of dysphoric manic mixed state can be extended to DH. In the latter, eutrophic exuberance is replaced by irritable-labile mood, and the hypomanic expansiveness finds expression in mental, psychomotor and behavioral activation that could involve increased drives (e.g., travel, substances, and sex) and social disinhibition. It is useful to contrast the foregoing picture of DH as hypomanic exuberance muted by leaden paralysis, with that of our previous work on DMX as a major depressive mixed state with more subtle excitatory hypomanic intrusions. We discuss methodologic, theoretical and practical implications of categorical (DH) and dimensional (DMX) conceptualizations of mixed states beyond mania.

Using technology to improve longitudinal studies: self-reporting with ChronoRecord in bipolar disorder

OBJECTIVES

Longitudinal studies are an optimal approach to investigating the highly variable course and outcome associated with bipolar disorder, but are expensive and often have missing data. This study validates patient self-reported mood ratings using a home computer-based system (ChronoRecord) with clinician mood ratings on the Hamilton Depression Rating scale (HAMD) and Young Mania Rating scale (YMRS), and investigates the patient acceptance of the technology.

METHODS

After brief training, outpatients with bipolar disorder were given the software version of an established paper based self-reporting form (ChronoSheet) to install on a home computer. Every day for 3 months, patients entered mood, medications, sleep, life events, and menstrual data. Weight was entered weekly.

RESULTS

Eighty of 96 (83%) patients returned 8662 days of data. The mean days of data returned was 114.7 +/- 32.3 SD The mean percentage of days missing for mood data was 6.1% +/- 9.3 SD, equivalent to missing 7.3 day of the 114.7 days. Self-reported ratings were strongly correlated with clinician HAMD ratings (-0.683, p < 0.001).

CONCLUSIONS

This study demonstrates concurrent validity between ChronoRecord and HAMD. Patients with bipolar disorder showed high acceptance of a computer-based system for self-reporting of daily data. Automation of data collection can reduce missing data and eliminate errors associated with data entry. This technology also enables on-going feedback for both patient and researcher during a long-term study.

Long-term inter-episode stability of syndromes underlying mania

OBJECTIVE

To explore the stability of diverse manic presentations across manic recurrences.

METHOD

A total of 253 bipolar patients who experienced two or more hospitalizations, because of consecutive manic (or mixed) episodes, during a 20-year period were included. All patients had second hospitalizations with an mean interval of 773 days, while 126 and 91 patients had third and fourth hospitalizations with mean intervals of 1559 and 2237 days from the index hospitalization, respectively. Seven symptom scores, previously factor-validated, were calculated.

RESULTS

Depressive mood, irritable aggression, psychomotor/thought inhibition, mania, emotional lability/agitation and psychosis were moderately correlated across the index and subsequent hospitalizations.

CONCLUSION

A majority of diverse manic presentations were stable across manic recurrences. The stability was not restricted to two consecutive recurrences but appeared widespread over the long-term course of bipolar disorder. The finding may serve for the development of more effective long-term treatment strategies and a clinically more reasonable subtyping of mania.

Proposed multidimensional structure of mania: beyond the euphoric-dysphoric dichotomy

BACKGROUND

Although the construct of depression has been subjected to numerous factor analytic studies and phenomenological subtypes of clinical relevance have been delineated, this is not the case for mania. The few available studies have reported at least two factors, which consist of euphoric versus dysphoric-hostile subtypes. Our objective was to replicate and further enrich this literature.

METHODS

In the EPIMAN French National Study we systematically evaluated 104 DSM-IV hospitalized manic patients in four university centers in different regions of France. Psychiatrists completed the Beigel-Murphy Manic State Rating Scale (MSRS), as well as the HAM-D(17), affective temperament scales, and the GAF Axis V from DSM-IV. Categorization of patients into pure versus dysphoric mania was made on the basis of clinical diagnosis, independent from psychometric measures.

RESULTS

On principal component analysis of the MSRS, three factors explained the largest variance: a global manic (23.3% variance), paranoid-hostile (14.8% variance), and psychotic (9.1% variance). After varimax rotation, we obtained seven independent factors: F1 Disinhibition-instability, F2 Paranoia-hostility, F3 Deficit, F4 Grandiosity-psychosis, F5 Elation-euphoria, F6 Depression, and F7 (Hyper)sexuality. We could not demonstrate significant correlations between the individual factors and impaired functioning on GAF. However, depressive and, to some extent, cyclothymic temperaments correlated with F6 Depression. Finally, intergroup comparisons between pure versus dysphoric mania diagnosed clinically showed high levels of F3 Deficit and F5 Elation in the pure, and of F6 Depression in dysphoric, mania; F2 Paranoia-hostility did not discriminate these two clinical forms of mania.

LIMITATIONS

Although the present analyses on the Beigel-Murphy represent the largest sample studied to date, they are still underpowered and do not guarantee a stable factorial structure. Our findings are cross-sectional and require prospective validation.

CONCLUSIONS

Our data suggest that 'dysphoria' as used in the literature to qualify mania is insufficiently precise, and is best further specified as 'depressive' versus 'irritable.' Moreover, our data extend the rich multidimensional phenomenology of mania beyond the existing literature: we submit that disinhibition-instability (a core 'activation' component) can, on the one hand, be associated with distinct emotional presentations (euphoric, depressive, or irritable-hostile), as well as psychotic and deficit symptomatology on the other.

Seasonal variation of mixed and pure episodes of bipolar disorder

BACKGROUND

Although seasonal patterns of manic episodes have been reported, the seasonal variation of mixed states of bipolar disorder has received little attention. In the current report we address that concern as well as the overall seasonality of manic episodes.

METHODS

The seasonal pattern of 304 psychiatric hospital admissions for treatment of mixed or manic bipolar episodes over a 3-year period were analyzed employing two definitions of mixed manic states: DSM-III-R and an ROC derived definition.

RESULTS

The frequency of all manic episodes combined peaked in early spring, with a nadir in late fall. Pure manic admissions showed a similar pattern. Mixed manic admissions had a significantly different pattern, with a peak in late summer and a nadir in November. The differences between pure and mixed manic admissions were demonstrated with the use of the ROC definition for mixed states.

LIMITATIONS

Effects of medications and medication non-compliance may dampen natural seasonal patterns of episodes.

CONCLUSIONS

The different seasonal pattern of mixed and pure manic episodes support the separation of mixed episodes as a distinct clinical subtype.