Screening for bipolar disorder: does gender distort scores and case-finding estimates?

BACKGROUND: Gender differences in rates of bipolar disorder have been described, with most studies reporting males as over-represented in those diagnosed with a bipolar I disorder and females over-represented in those diagnosed with a bipolar II disorder. This could reflect true differences in prevalence or measurement error emerging from screening or case-finding measures. We examine the possible contribution of the latter by examining one screening measure-the Mood Swings Questionnaire (MSQ). METHODS: We analyse MSQ data from a large sample of age- and gender-matched bipolar I and bipolar II patients (and their composite group). Gender differences were examined in terms of prevalence and severity of MSQ symptoms, MSQ sub-scales scores and total MSQ scores, employing univariate and differential item functioning (DIF) analyses. RESULTS: Both male and female bipolar I patients reported higher total MSQ and higher mysticism MSQ sub-scale scores than their male and female bipolar II counterparts. There were no gender differences when bipolar I, bipolar II and composite bipolar groups were separately examined on both total and sub-scale MSQ scores, suggesting that gender does not impact on MSQ scoring. When item analyses of bipolar I and II groups were undertaken separately, a number of differences emerged, but as few were consistent across bipolar sub-types such differences could reflect chance and failure to control for multiple comparisons. The over-representation of some items in females and some in males may have contributed to the comparable total and sub-scale scores. LIMITATIONS: Large sample size and only one measure (i.e. MSQ) examined. CONCLUSION: As total and sub-scale MSQ scores were uninfluenced by gender we can conclude that this screening test is not confounded by gender and, if representative of other such screening measures, would indicate that any differential prevalence of the bipolar disorders identified in community studies possibly reflects gender differences in their occurrence rather than artefactual consequences of screening measures having a gender bias.

The impact of being newly diagnosed with a bipolar disorder and the short-term outcome of disorder-specific management.

OBJECTIVES: The aim of the study was to determine the impact of a first-time diagnosis of bipolar disorder in patients previously generally managed as having a unipolar disorder, and to quantify the impact of disorder-specific management strategies for such newly diagnosed patients over the following three months. METHODS: A total of 157 patients receiving a diagnosis of bipolar disorder for the first time by a psychiatrist at a specialist depression clinic completed a research interview and questionnaires, with 106 (68%) also completing 12-week quantitative and qualitative evaluations. Assessing psychiatrists undertook baseline and follow-up assessments recording management changes, reactions to the diagnosis and global changes in functioning over time. RESULTS: The majority of patients had a positive response to receiving a diagnosis of bipolar disorder, and most implemented a number of clinician-suggested bipolar management strategies. Patients showed improvement on five of the six self-report measures over the three-month study period. Multivariate analyses quantified lamotrigine as making the most distinctive contribution to 'improver' status, particularly for the bipolar II disorder subset. CONCLUSIONS: Results are encouraging in identifying a generally positive acceptance of a diagnosis of bipolar disorder, improved outcome following the introduction of diagnostic-specific management components, and a distinctive contribution of lamotrigine to improved three-month outcome.

Self-reported creativity in bipolar disorder: prevalence, types and associated outcomes in mania versus hypomania.

BACKGROUND: Bipolar (BP) disorder has been linked to creativity following investigation of prominent artists and controlled trials of creativity in BP disorder patients. However, it is unclear whether creativity is differentially expressed across the BP I and BP II subtypes. METHODS: 219 patients (aged 19-63 years) diagnosed with BP disorder by clinical interview and DSM-IV criteria were asked whether they tended to be more creative during hypo/manic episodes, and answered five questions about personality styles associated with creativity. Qualitative analyses were performed on a smaller subset of 69 BP patients (n=19 BP I, n=50 BP II) who provided written responses of the types of creative activities engaged in when hypo/manic and any perceived advantages or disadvantages of their creative pursuits. RESULTS: 82% of BP patients affirmed being creative when hypo/manic, with comparable results for the BP I and BP II subtypes (84% and 81% respectively). Both BP subtypes engaged mostly in writing, painting, work or business ideas and 'other' forms of art; however BP II patients were more likely to draw and be musical. Both subgroups reported the consequences of feeling good, being productive or quitting their project. BP I patients were more likely to overspend during their creative highs while BP II patients were more likely to experience improved focus and clarity. BP patients affirming creative highs were significantly more likely to report creative personality styles more generally outside of a mood episode. LIMITATIONS: BP patients' self-reported creative activities were not retrospectively judged for quality or originality and so may reflect common creative abilities rather than exceptional quality. The impact of depressive episodes on creativity was not assessed. Uneven sample sizes in the BP I and BP II subgroups may have compromised statistical power. CONCLUSION: Creativity during hypo/manic episodes was extremely common in both BP subtypes. While some nuances in activity type and outcomes were observed, no significant creative phenotype specific to BP I or BP II disorder emerged.

Differentiation of bipolar I and II disorders by examining for differences in severity of manic/hypomanic symptoms and the presence or absence of psychosis during that phase.

BACKGROUND: DSM-IV criteria for mania/hypomania overlap considerably. We sought to examine the utility of a model differentiating bipolar I and II disorders by weighting the presence or absence of psychosis during manic/hypomanic episodes as opposed to simply weighting symptom severity. METHODS: A set of 632 patients with a so-assigned clinical bipolar I or II disorder diagnosis contributed to the principal analyses, and a subset of 210 was included in a comparative analyses of DSM-assigned diagnoses. We also examined the impact of duration of highs on symptom patterns and the extent to which depressive episodes were psychotic or non-psychotic melancholic in type. RESULTS: There were no group differences for bipolar I and II patients (clinical or DSM groups) by age, gender, age of onset or age of formal bipolar diagnosis. Clinically assigned bipolar I patients returned higher severity scores than bipolar II patients on manic/hypomanic symptoms, but such differentiation was limited. Clinically-assigned bipolar I patients were more likely than bipolar II patients to be diagnosed with psychotic depression, and had lower rates of non-melancholic depression. Duration of highs had some impact on the phenomenology of highs, but not on the phenomenology of depression. LIMITATIONS: We cannot establish the degree to which clinicians validly differentiated those with bipolar disorder, and accurately judged the lifetime presence of psychotic features and of depressive subtype differentiation. CONCLUSIONS: Findings support the utility of an alternative model to DSM-IV in weighting the respective presence or absence of psychotic symptoms during highs in differentiating bipolar I and II disorders.

Validation of a new prototypic measure of melancholia.

Multiple approaches have been adopted in an attempt to effectively identify and discriminate melancholic and non-melancholic depressive subtypes. We recently developed the Sydney Melancholia Prototype Index (SMPI) which incorporates antecedent and illness course variables as well as symptoms, with clinician-rated and self-rated SMPI versions, and with the former having been shown to have superior sensitivity and specificity in discriminating melancholic from non-melancholic depression. The aim of this study was to further evaluate the capacity of the SMPI to identify melancholia in comparison to DSM-based and clinician-judged assignments. The sample comprised 214 patients diagnosed with melancholic or non-melancholic depression according to a detailed clinical assessment and by the Mini International Neuropsychiatric Structured Interview (MINI) assessing formal DSM-IV melancholia criteria. DSM-IV assignment to melancholic versus non-melancholic depression was contrasted with clinician-judged allocation, the combination of these two strategies ("concordant diagnoses"), and to the SMPI (CR or clinician-rated and SR or self-report versions), with the likely validity of each approach examined against historical ascriptions for melancholia. DSM-IV criteria assigned the highest percentage of the sample with a melancholic diagnosis (64%), whereas the SMPI-SR assigned the smallest percentage with a melancholic diagnosis (37%). DSM-IV assignment was associated with the fewest number of validating variables, whilst SMPI-CR and independent clinician diagnosis were associated with the greatest number of differentiating variables including negative childhood experiences, past and recent stressors, satisfaction with life and perceived social support. These comparative analyses provide further support for the SMPI-CR in identifying and discriminating melancholic depression from non-melancholic depression. Replication of these findings in other samples with independent raters is recommended.

Does age impact on rating melancholic and non-melancholic depressive symptoms?

BACKGROUND: Melancholic depression has long evaded attempts at accurate definition. A range of factors may influence symptom reporting and so compromise definitional attempts. One possible factor is age, and its possible influence led to the current study examining the impact of age on the reporting of melancholic and non-melancholic depressive symptoms. METHODS: A set of 32 self-rated depression items from the SDS depression measure and weighted to both melancholic and non-melancholic depressions were analysed for any impact of age in clinically diagnosed melancholic and non-melancholic depressed patients. RESULTS: Melancholic and non-melancholic patients did not differ by gender, severity of depression or duration of current episode. None of the melancholic items from the SDS showed a linear increase with age. Analyses of factor analytic derived constructs identified one factor as evidencing a linear decrease (rather than increase) in scores with age in the melancholic patients. Differential item functioning was only found for melancholic patients' scores on the 'non-melancholic scale', with a decrease across age. Simulated data revealed, for the same scale, a decrease in both melancholic and non-melancholic patients. LIMITATIONS: Our assessment strategies effectively excluded those with severe melancholia and who were unable to complete self-report measures, and may have contributed to study findings. As we had few patients over the age of 70, age effects in elderly patients may have missed identification. CONCLUSIONS: We found no evidence for melancholic symptoms to increase in severity with age. To the contrary, some items decreased in severity with age in both melancholic and non-melancholic patients. Overall study results are reassuring in indicating that age is unlikely to distort analyses seeking to differentiate those with melancholic and non-melancholic depressive conditions.

Do practitioners managing mood disorders work to a sub-typing or a 'one size fits all' model?

OBJECTIVE: To assess whether psychiatrists in the community operate to a sub-typing model of mood disorders when choosing psychotropic medications. METHOD: Patients assessed through the Black Dog Institute depression clinic provided information on their previously prescribed and current medications, on how effective they found them and whether they had to be ceased due to side-effects. The prevalence of each medication trialled was analysed according to diagnosis (bipolar I, bipolar II, unipolar melancholic depression or unipolar non-melancholic depression). RESULTS: Analyses indicate that psychiatrists prescribe medications differentially in line with diagnosis. This effect was found in both previously prescribed and currently prescribed medications, and was most distinct for mood stabiliser and antipsychotic medications. Several medications, in contrast, appeared to have been trialled by the majority of patients, regardless of diagnosis. Analyses of effectiveness and cessation due to side-effects were compromised by small sub-sample sizes. CONCLUSIONS: Psychiatrists in the community appear to operate to a sub-typing model of mood disorders, preferentially prescribing many medications according to mood disorder sub-type.

The categorisation of dysthymic disorder: can its constituents be meaningfully apportioned?

BACKGROUND: Since its introduction in DSM-III, the validity of dysthymia has been debated. Our objective is to further examine the concept of dysthymia in an outpatient sample, and explore whether its constituents can be meaningfully apportioned. METHODS: 318 patients attending the Black Dog Institute Depression Clinic were assessed by the Mini-International Neuropsychiatric Interview, and completed several self-report measures, in addition to a clinical assessment by an Institute psychiatrist. The characteristics of patients with major depressive disorder (MDD), dysthymic disorder and double depression were examined. Latent Class Analysis (LCA) and Latent Profile Analysis (LPA) were then conducted with the aim of detecting distinct classes based on depressive symptomatology and personality domains, respectively. Finally, clinicians' formulations of the study patients were examined. RESULTS: Depression groups mainly differed on parameters of severity. Although LCA and LPA analyses indicated the presence of distinct classes, these only moderately correlated with the MINI-diagnosed groups. Finally, there was evidence for considerable heterogeneity within clinicians' formulations of dysthymia. LIMITATIONS: Inadequate sample numbers for various measures limited the power of the LPA and our sample was weighted to patients with a more severe depressive condition which may affect the detection of a distinct 'dysthymic' personality profile. CONCLUSIONS: Despite employing a variety of techniques, we were unable to obtain a clear homogeneous picture of dysthymia. Rather, there was evidence for a distinct heterogeneity in clinician-derived diagnoses. These findings allude to the questionable discriminant validity of dysthymia and may encourage future research and discussion on this important topic.

A diagnostic profile of those who return a false positive assignment on bipolar screening measures.

OBJECTIVES: Our aim was to identify the diagnostic profile of patients classified as 'false positives' on two bipolar screening measures; the Mood Swings Questionnaire (MSQ) and the Mood Disorders Questionnaire (MDQ). METHODS: A total of 1534 patients attending the Black Dog Institute Depression Clinic completed the MSQ-46, and a smaller subset of 852 completed the MDQ. All patients underwent clinical assessment by one or more Institute psychiatrists. RESULTS: Using clinical assignment (i.e. bipolar vs. unipolar) as the criterion measure for assessing the screening measures, the overall agreement rates were 84% for the MSQ-46 and 74% for the MDQ. Patients identified as 'false positives' were most likely to be clinically diagnosed as having a unipolar non-melancholic depression (37% for MSQ-46; 46% for MDQ), or a primary anxiety condition with secondary non-melancholic depression (19% for MSQ-46; 15% for MDQ). In addition, within the unipolar non-melancholic group, 46% of the MSQ-46 assigned false positives and 63% of the MDQ assigned false positives had co-morbid anxiety conditions. CONCLUSIONS: These findings suggest that patients with anxiety conditions account for a significant proportion of false positive diagnoses on bipolar screening tests - a finding that should be conceded in the development and refinement of such screening measures and in clinical assessment of the possibility of a bipolar disorder.

Does testing for bimodality clarify whether the bipolar disorders are categorically or dimensionally different to unipolar depressive disorders?

BACKGROUND: It has been held that if bipolar disorder is categorically distinct, it should differentiate from unipolar depressive disorders by showing bimodality or a 'zone of rarity' in bipolar symptom scores. Two previous studies have failed to demonstrate bimodality. We undertook a third study. METHODS: A total of 1106 patients attending the Black Dog Institute Depression Clinic completed the Mood Disorders Questionnaire (MDQ), in addition to undergoing clinical assessment by an Institute psychiatrist. RESULTS: The distributions of scores for the total number of hypomanic symptoms endorsed by unipolar and bipolar patients were both skewed, with the bipolar group endorsing a high number of hypomanic symptoms and the unipolar group endorsing few symptoms--and so giving the impression of an 'even' distribution generated by two quite distinctly differing sub-groups. However, formal statistical analyses involving mixed modelling provided no clear evidence that a bimodal distribution provided a better fit to the data than a unimodal one. CONCLUSIONS: Failure to statistically demonstrate a 'point of rarity' did not marry with visual inspection of the plotted data--which clearly suggested two groups putatively capturing those with bipolar and unipolar disorders respectively. The paper considers some limitations to the emphasis on 'bimodality' in differentiating potentially differing conditions.