Background: Despite increasing interest in dimensional psychopathology and the use of symptom clusters in clinical research, factor analytic studies of mania are rare. Most studies included not only manic patients, but also patients with a mixed episode or other severe mental disorders. We aimed at further elucidating the symptom structure of manic states.
Methods: As part of a national survey of acute psychiatric inpatient care, all patients admitted to a random sample of Italian public and private facilities during an index period underwent a standardized assessment, including the 24-item Brief Psychiatric Rating Scale (BPRS-24). Eighty-eight patients (90% of all manic patients admitted) with an ICD-10 diagnosis of Bipolar Affective Disorder, Current Episode Manic with complete data were included in this study. Principal axis factor analysis with Varimax rotation was performed on BPRS-24 items.
Results: Four factors were extracted, explaining 51% of total variance. They were interpreted as Mania, Disorganization, Positive Symptoms, and Dysphoria. The distribution of the Disorganization factor was positively skewed, with most patients relatively free from disorganization symptoms and some patients showing varying degrees of severity.
Limitations: The sample size was relatively small; also, patients were not administered a structured diagnostic interview. However, reasonably large samples are usually sufficient when communalities are high. Also, the manic episode is a clear-cut diagnostic entity easily identified by experienced clinicians, and the independent BPRS-24 ratings corroborated the diagnosis.
Conclusions: The identification of a Mania, Positive Symptoms, and Dysphoria factor is consistent with most previous studies. The identification of a Disorganization factor in a sample including only manic patients is a new finding that may have clinical implications, as its distribution suggests the possibility of distinguishing two patient groups, which may require different interventions to achieve optimal therapeutic response. The factorially derived BPRS-24 subscales may be useful for evaluation of treatment effects in clinical trials of antimanic agents.