Camilo J. Ruggero

New Dimensions in the Quantitative Classification of Mental Illness

CONTEXT Patterns of comorbidity among mental disorders are thought to reflect the natural organization of mental illness. Factor analysis can be used to investigate this structure and construct a quantitative classification system. Prior studies identified 3 dimensions of psychopathology: internalizing, externalizing, and thought disorder. However, research has largely relied on common disorders and community samples. Consequently, it is unclear how well the identified organization applies to patients and how other major disorders fit into it. OBJECTIVE To analyze comorbidity among a wide range of Axis I disorders and personality disorders (PDs) in the general outpatient population. DESIGN Clinical cohort study. SETTING A general outpatient practice, the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project. PARTICIPANTS Outpatients (N = 2900) seeking psychiatric treatment. MAIN OUTCOME MEASURES The Structured Clinical Interview for DSM-IV and the Structured Interview for DSM-IV Personality. RESULTS We tested several alternative groupings of the 25 target disorders. The DSM-IV organization fit the data poorly. The best-fitting model consisted of 5 factors: internalizing (anxiety and eating disorders, major depressive episode, and cluster C, borderline, and paranoid PDs), externalizing (substance use disorders and antisocial PD), thought disorder (psychosis, mania, and cluster A PDs), somatoform (somatoform disorders), and antagonism (cluster B and paranoid PDs). CONCLUSIONS We confirmed the validity of the 3 previously found spectra in an outpatient population. We also found novel somatoform and antagonism dimensions, which this investigation was able to detect because, to our knowledge, this is the first study to include a variety of somatoform and personality disorders. The findings suggest that many PDs can be placed in Axis I with related clinical disorders. They also suggest that unipolar depression may be better placed with anxiety disorders than with bipolar disorders. The emerging quantitative nosology promises to provide a more useful guide to clinicians and researchers.

The Hierarchical Taxonomy of Psychopathology (HiTOP) : A Dimensional Alternative to Traditional Nosologies

The reliability and validity of traditional taxonomies are limited by arbitrary boundaries between psychopathology and normality, often unclear boundaries between disorders, frequent disorder co-occurrence, heterogeneity within disorders, and diagnostic instability. These taxonomies went beyond evidence available on the structure of psychopathology and were shaped by a variety of other considerations, which may explain the aforementioned shortcomings. The Hierarchical Taxonomy Of Psychopathology (HiTOP) model has emerged as a research effort to address these problems. It constructs psychopathological syndromes and their components/subtypes based on the observed covariation of symptoms, grouping related symptoms together and thus reducing heterogeneity. It also combines co-occurring syndromes into spectra, thereby mapping out comorbidity. Moreover, it characterizes these phenomena dimensionally, which addresses boundary problems and diagnostic instability. Here, we review the development of the HiTOP and the relevant evidence. The new classification already covers most forms of psychopathology. Dimensional measures have been developed to assess many of the identified components, syndromes, and spectra. Several domains of this model are ready for clinical and research applications. The HiTOP promises to improve research and clinical practice by addressing the aforementioned shortcomings of traditional nosologies. It also provides an effective way to summarize and convey information on risk factors, etiology, pathophysiology, phenomenology, illness course, and treatment response. This can greatly improve the utility of the diagnosis of mental disorders. The new classification remains a work in progress. However, it is developing rapidly and is poised to advance mental health research and care significantly as the relevant science matures.

Development of a measure of experiential avoidance: The Multidimensional Experiential Avoidance Questionnaire.

Experiential avoidance (EA) has been conceptualized as the tendency to avoid negative internal experiences and is an important concept in numerous conceptualizations of psychopathology as well as theories of psychotherapy. Existing measures of EA have either been narrowly defined or demonstrated unsatisfactory internal consistency and/or evidence of poor discriminant validity vis-à-vis neuroticism. To help address these problems, we developed a reliable self-report questionnaire assessing a broad range of EA content that was distinguishable from higher order personality traits. An initial pool of 170 items was administered to a sample of undergraduates (N = 312) to help evaluate individual items and establish a structure via exploratory factor analyses. A revised set of items was then administered to another sample of undergraduates (N = 314) and a sample of psychiatric outpatients (N = 201). A 2nd round of item evaluation was performed, resulting in a final 62-item measure consisting of 6 subscales. Cross-validation data were gathered in 3 new, independent samples (students, N = 363; patients, N = 265; community adults, N = 215). The resulting measure (the Multidimensional Experiential Avoidance Questionnaire, or MEAQ) exhibited good internal consistency, was substantially associated with other measures of avoidance, and demonstrated greater discrimination vis-à-vis neuroticism relative to preexisting measures of EA. Furthermore, the MEAQ was broadly associated with psychopathology and quality of life, even after controlling for the effects of neuroticism.

Diagnostic shifts during the decade following first admission for psychosis.

OBJECTIVE Diagnostic shifts have been prospectively examined in the short term, but the long-term stability of diagnoses has rarely been evaluated. The authors examined diagnostic shifts over a 10-year follow-up period. METHOD A cohort of 470 first-admission patients with psychotic disorders was systematically assessed at baseline and at 6-month, 2-year, and 10-year follow-ups. Longitudinal best-estimate consensus diagnoses were formulated after each assessment. RESULTS At baseline, the diagnostic distribution was 29.6% schizophrenia spectrum disorders, 21.1% bipolar disorder with psychotic features, 17.0% major depression with psychotic features, 2.4% substance-induced psychosis, and 27.9% other psychoses. At year 10, the distribution changed to 49.8%, 24.0%, 11.1%, 7.0%, and 8.1%, respectively. Overall, diagnoses were changed for 50.7% of study participants at some point during the study. Most participants who were initially diagnosed with schizophrenia or bipolar disorder retained the diagnosis at year 10 (89.2% and 77.8%, respectively). However, 32.0% of participants (N=98) originally given a non-schizophrenia diagnosis had gradually shifted to a schizophrenia diagnosis by year 10. The second largest shift was to bipolar disorder (10.7% of those not given this diagnosis at baseline). Changes in the clinical picture explained many diagnostic shifts. In particular, poorer functioning and greater negative and psychotic symptom ratings predicted a subsequent shift to schizophrenia. Better functioning and lower negative and depressive symptom ratings predicted the shift to bipolar disorder. CONCLUSIONS First-admission patients with psychotic disorders run the risk of being misclassified at early stages in the illness course, including more than 2 years after first hospitalization. Diagnosis should be reassessed at all follow-up points.

Development and Validation of New Anxiety and Bipolar Symptom Scales for an Expanded Version of the IDAS (the IDAS-II)

The original Inventory of Depression and Anxiety Symptoms (IDAS) contains 11 nonoverlapping scales assessing specific depression and anxiety symptoms. In creating the expanded version of the IDAS (the IDAS-II), our goal was to create new scales assessing other important aspects of the anxiety disorders as well as key symptoms of bipolar disorder. Factor analyses of the IDAS-II item pool led to the creation of seven new scales (Traumatic Avoidance, Checking, Ordering, Cleaning, Claustrophobia, Mania, Euphoria) plus an expanded version of Social Anxiety. These scales are internally consistent and show strong convergent and significant discriminant validity in relation to other self-report and interview-based measures of anxiety, depression, and mania. Furthermore, the scales demonstrate substantial criterion and incremental validity in relation to interview-based measures of DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, fourth edition) symptoms and disorders. Thus, the expanded IDAS-II now assesses a broad range of depression, anxiety, and bipolar symptoms.

Psychiatric diagnoses in patients previously overdiagnosed with bipolar disorder.

OBJECTIVE In a previous article from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we reported that bipolar disorder is often overdiagnosed in psychiatric outpatients. An important question not examined in that article was what diagnoses were given to the patients who had been overdiagnosed with bipolar disorder. In the present report from the MIDAS project, we examined whether there was a particular diagnostic profile associated with bipolar disorder overdiagnosis. METHOD Eighty-two psychiatric outpatients reported having been previously diagnosed with bipolar disorder that was not confirmed when they were interviewed with the Structured Clinical Interview for DSM-IV (SCID). Psychiatric diagnoses were compared in these 82 patients and in 528 patients who were not previously diagnosed with bipolar disorder. Patients were interviewed by a highly trained diagnostic rater who administered a modified version of the SCID for DSM-IV Axis I disorders and the Structured Interview for DSM-IV Personality for DSM-IV Axis II disorders. This study was conducted from May 2001 to March 2005. RESULTS The most frequent lifetime diagnosis in the 82 patients previously diagnosed with bipolar disorder was major depressive disorder (82.9%, n = 68). The patients overdiagnosed with bipolar disorder were significantly more likely to be diagnosed with borderline personality disorder compared to patients who were not diagnosed with bipolar disorder (24.4% vs 6.1%; P < .001). A previous diagnosis of bipolar disorder was also associated with significantly higher lifetime rates of major depressive disorder (P < .01), posttraumatic stress disorder (P < .05), impulse control disorders (P < .05), and eating disorders (P < .05), although only the association with impulse control disorders remained significant after controlling for the presence of borderline personality disorder. CONCLUSIONS Psychiatric outpatients overdiagnosed with bipolar disorder were characterized by more Axis I and Axis II diagnostic comorbidity in general, and borderline personality disorder in particular.

Borderline Personality Disorder and the Misdiagnosis of Bipolar Disorder

Recent reports suggest bipolar disorder is not only under-diagnosed but may at times be over-diagnosed. Little is known about factors that increase the odds of such mistakes. The present work explores whether symptoms of borderline personality disorder increase the odds of a bipolar misdiagnosis. Psychiatric outpatients (n=610) presenting for treatment were administered the Structured Clinical Interview for DSM-IV (SCID) and the Structured Interview for DSM-IV Personality for DSM-IV axis II disorders (SIDP-IV), as well as a questionnaire asking if they had ever been diagnosed with bipolar disorder by a mental health care professional. Eighty-two patients who reported having been previously diagnosed with bipolar disorder but who did not have it according to the SCID were compared to 528 patients who had never been diagnosed with bipolar disorder. Patients with borderline personality disorder had significantly greater odds of a previous bipolar misdiagnosis, but no specific borderline criterion was unique in predicting this outcome. Patients with borderline personality disorder, regardless of how they meet criteria, may be at increased risk of being misdiagnosed with bipolar disorder.

Screening for Bipolar Disorder and Finding Borderline Personality Disorder

OBJECTIVE Bipolar disorder and borderline personality disorder share some clinical features and have similar correlates. It is, therefore, not surprising that differential diagnosis is sometimes difficult. The Mood Disorder Questionnaire (MDQ) is the most widely used screening scale for bipolar disorder. Prior studies found a high false-positive rate on the MDQ in a heterogeneous sample of psychiatric patients and primary care patients with a history of trauma. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services project, we examined whether psychiatric outpatients without bipolar disorder who screened positive on the MDQ would be significantly more often diagnosed with borderline personality disorder than patients who did not screen positive. METHOD The study was conducted from September 2005 to November 2008. Five hundred thirty-four psychiatric outpatients were interviewed with the Structured Clinical Interview for DSM-IV and Structured Interview for DSM-IV Personality Disorders and asked to complete the MDQ. Missing data on the MDQ reduced the sample size to 480. Approximately 10% of the study sample were diagnosed with a lifetime history of bipolar disorder (n = 52) and excluded from the initial analyses. RESULTS Borderline personality disorder was 4 times more frequently diagnosed in the MDQ positive group than the MDQ negative group (21.5% vs 4.1%, P < .001). The results were essentially the same when the analysis was restricted to patients with a current diagnosis of major depressive disorder (27.6% vs 6.9%, P = .001). Of the 98 patients who screened positive on the MDQ in the entire sample of patients, including those diagnosed with bipolar disorder, 23.5% (n = 23) were diagnosed with bipolar disorder, and 27.6% (n = 27) were diagnosed with borderline personality disorder. CONCLUSIONS Positive results on the MDQ were as likely to indicate that a patient has borderline personality disorder as bipolar disorder. The clinical utility of the MDQ in routine clinical practice is uncertain.

Comparing Methods for Scoring Personality Disorder Types Using Maladaptive Traits in DSM-5

The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th ed.) Section III will include an alternative hybrid system for the diagnosis of personality disorder (PD). This alternative system defines PD types partly through specific combinations of maladaptive traits, rather than by using a set of polythetic diagnostic criteria. The current report utilizes a large sample of undergraduates (n = 1,159) to examine three dimensional methods for comparing an individual’s trait profile to each PD type. We found that the sum of an individual’s scores on the assigned traits obtained large convergent correlations (Mdn r =.61) and best reproduced the patterns of PD discriminant correlations observed within the DSM-IV measure. We also tested the DSM-5 Section III model algorithms and compared them with different thresholds for assigning categorical diagnoses. Frequency rates using the algorithms were greatly reduced, whereas requiring half of the assigned traits produced rates that more closely approximated current prevalence estimates. Our research suggests that DSM-5 Section III trait model can reproduce the DSM-IV-TR PD constructs and identifies effective methods of doing so.

Ten‐year diagnostic consistency of bipolar disorder in a first‐admission sample

OBJECTIVES A number of reports have examined the stability of the diagnosis of schizophrenia, but fewer studies have considered the long-term consistency of a bipolar diagnosis or factors that influence the likelihood of a diagnostic change. The present study sought to estimate how consistently a bipolar diagnosis was made across a 10-year period and factors associated with consistency, particularly demographic and clinical characteristics, childhood-related factors, and illness course. METHODS The sample included 195 first-admission patients presenting with psychosis who were assessed soon after hospitalization and at 6-month, 2-year, and 10-year follow-up and diagnosed with bipolar disorder on at least one of these assessments. Diagnoses were made using best-estimate procedures and were blind to all previous consensus diagnoses. Respondents who were consistently diagnosed with bipolar disorder were compared to those whose diagnosis shifted across assessments. RESULTS Overall, 50.3% (n = 98) of the 195 respondents were diagnosed with bipolar disorder at every available assessment, but 49.7% (n = 97) had a diagnostic shift to a non-bipolar disorder at least once over the course of the 10-year study. Childhood psychopathology and poorer illness course were among the few variables associated with increased odds of a change in diagnosis. CONCLUSIONS Even with optimal assessment practices, misdiagnosis of bipolar disorder is common, with complex clinical presentations often making it difficult to consistently diagnose the disorder over the long term.