Quality of life among bipolar disorder patients misdiagnosed with major depressive disorder.
OBJECTIVE
Bipolar disorder is frequently misdiagnosed as major depressive disorder (MDD). We aim to quantify the prevalence of misdiagnosed bipolar disorder among the depression population and evaluate the quality-of-life (QOL) impact of misdiagnoses.


METHODS
Data were collected from 2 self-administered, cross-sectional studies in 2003. Patients participating in The Bipolar Disorder Misdiagnosis Study (N = 1156) were previously diagnosed with depression, experienced a depressive episode within the past year, and had no previous diagnosis of bipolar disorder or schizophrenia. Patients who experienced a manic episode in the past year, based on DSM-IV criteria, were classified as misdiagnosed. Patients participating in The Bipolar Disorder Project (N = 1214) self-reported a diagnosis of bipolar disorder and were recruited through community mental health centers and support groups. Quality of life was assessed via the Psychological General Well-Being (PGWB) Index and Medical Outcomes Study 8-Item Short-Form Health Survey (SF-8). Demographic differences between groups were controlled using linear regression models.


RESULTS
Of the diagnosed MDD sample, 14.3% met criteria for misdiagnosed bipolar disorder. When controlling for demographic differences, the PGWB overall score for the misdiag-nosed averaged 12.77 (p < .001) points lower than that of MDD patients and 9.55 (p < .001) points lower than that of diagnosed bipolar disorder patients. The average SF-8 mental component summary score for the misdiagnosed was 5.85 (p < .001) points lower than that of MDD patients and 3.18 (p = .002) points lower than that of diagnosed bipolar disorder patients.


CONCLUSIONS
Misdiagnosis is associated with poorer QOL than MDD or diagnosed bipolar disorder, which are recognized as having a considerable impact on QOL.
Awad
A George
AG
Humber River Regional Hospital, Toronto, Ontario, Canada.
Rajagopalan
Krithika
K
Bolge
Susan C
SC
McDonnell
Diana D
DD