Differential diagnosis of bipolar affective disorder type II and borderline personality disorder: analysis of the affective dimension.

Background: Differential diagnosis between bipolar affective disorder type II and borderline personality disorder can be problematic yet a priority for effective treatment planning. Diagnosis is problematic when symptoms do not present enough intensity or duration to clear the issue but also when there is a relative overlap of criteria between both disorders. If for many patients, the diagnosis is more easily differentiated, confounding conditions are found in 20% of cases for which it becomes a significant issue.

Method: A research with the key words affective instability, borderline personality disorder, and bipolar disorder on Medline and Psych-Info was done. Other references were found through this review in related articles. Comparison of data about the affective dimensions concerning bipolar disorder and borderline personality disorder was noted.

Results: Affective instability is a confounding factor: quality and intensity of affects, speed of fluctuations, affective response to social stress, and its modulation are core elements of affective instability that need to be analyzed to clarify a proper diagnosis.

Limitations: There is further necessity for research about affective instability in the 2 diagnoses.

Conclusions: Making a valid differential diagnosis has an important clinical value in order for the clinician to plan proper treatment. Analysis of the affective experience and its qualitative and quantitative facets can help establish it.