Psychopathologic structure of bipolar disorders: exploring dimensional phenotypes, their relationships, and their associations with bipolar I and II disorders.

BACKGROUND: Given its diverse disease courses and symptom presentations, multiple phenotype dimensions with different biological underpinnings are expected with bipolar disorders (BPs). In this study, we aimed to identify lifetime BP psychopathology dimensions. We also explored the differing associations with bipolar I (BP-I) and bipolar II (BP-II) disorders. METHODS: We included a total of 307 subjects with BPs in the analysis. For the factor analysis, we chose six variables related to clinical courses, 29 indicators covering lifetime symptoms of mood episodes, and 6 specific comorbid conditions. To determine the relationships among the identified phenotypic dimensions and their effects on differentiating BP subtypes, we applied structural equation modeling. RESULTS: We selected a six-factor solution through scree plot, Velicer's minimum average partial test, and face validity evaluations; the six factors were cyclicity, depression, atypical vegetative symptoms, elation, psychotic/irritable mania, and comorbidity. In the path analysis, five factors excluding atypical vegetative symptoms were associated with one another. Cyclicity, depression, and comorbidity had positive associations, and they correlated negatively with psychotic/irritable mania; elation showed positive correlations with cyclicity and psychotic/irritable mania. Depression, cyclicity, and comorbidity were stronger in BP-II than in BP-I, and they contributed significantly to the distinction between the two disorders. CONCLUSIONS: We identified six phenotype dimensions; in addition to symptom features of manic and depressive episodes, various comorbidities and high cyclicity constructed separate dimensions. Except for atypical vegetative symptoms, all factors showed a complex interdependency and played roles in discriminating BP-II from BP-I.

Lifetime psychopathological characteristics associated with comorbid obsessive-compulsive disorder in clinically stable patients with chronic schizophrenia.

Obsessive-compulsive symptoms (OCS) commonly occur in the course of schizophrenia. The aim of this study was to investigate the rate of obsessive-compulsive disorder (OCD) in patients with chronic schizophrenia and evaluate lifetime correlates of the comorbidity. Subjects were clinically stable patients with chronic schizophrenia (n = 320). Patients having comorbid OCD and those without OCD were compared in terms of symptoms dimensions and cognitive function. OCD was found in 20.6 % of subjects. Earlier age at onset, male gender, higher level of education, comorbid panic disorder, and specific phobia were associated with comorbid OCD. In terms of lifetime symptoms, depression (p = 0.001) and anxiety (p = 0.014) showed significant association with the comorbidity, which corroborates with our previous study findings regarding OCD in bipolar disorder. In addition, decreased emotional response (p = 0.016), less formal thought disorder (p = 0.007), and less prodromal impairment (p = 0.005) were independently associated with the comorbidity. The OCD group showed better performance in working memory domain (p = 0.027) while other cognitive domains did not show any significant difference between the two groups. Association of OCSs with depressive symptoms and other comorbid anxiety disorders seems to be a common finding across schizophrenia and bipolar disorder. This study also suggests that comorbidity of OCD in schizophrenia is associated with less impairment of thought process and cognitive function throughout the disease course.