Functioning worsens in patients with bipolar, MDD only during depressive episodes

A longitudinal study assessing illness progression in patients with bipolar disorder and major depressive disorder found a worsening of patient function with depressive episodes, but an overall improvement in functioning over 5 years.

The study, which was published in Psychiatry Research, sought to assess the progression of functional impairment over time in young adults with bipolar disorder and MDD, particularly when patients were in states of euthymia.

The researchers hypothesized that significant illness progression would take place most prominently during states of patient euthymia.

“Emerging adulthood is a stage of life where significant transitions occur, including in mood disorder severity, and thus this could be a population especially sensitive to detecting changes in functioning,” Clarisse de Azambuja Farias and colleagues wrote. “Since there is even less information on the progression of major depression, the group consisting of individuals with MDD was added both to offer novel information and to act as an active control group.”

The study assessed 231 young adults aged 18 to 24 years from Pelotas, Brazil, over a period of 5 years using the Mini International Neuropsychiatric Interview, once at baseline and again 5 years later to determine the progression of mental disorders among the sample. Researchers also used the Structured Clinical Interview for DSM-IV to confirm patient diagnosis and the reliability of data. Among the sample, 83 participants were diagnosed with major depression and 55 with bipolar disorder (33 type I and 22 type II). Additionally, a control group of 93 participants with no diagnosed condition was included to provide a baseline.

The Functioning Assessment Short Test (FAST) was used to assess significant elements of participants’ lives, including autonomy, occupational functioning, cognition, relationships and leisure time across a 24-item scale. Increased impairment of the patient is associated with a higher FAST score. The FAST test was also given at both baseline and after 5 years.

“In the final adjusted multivariable model, contrary to our hypothesis, there was no significant effect of time on functioning,” Farias and colleagues wrote. “The bipolar disorder group had significantly more functional impairments in comparison to those with major depression and no mood disorders. Current depressive episodes also had a significant main effect, whereas (hypo)manic episodes did not have a significant effect.”

A total of 207 of the 231 participants returned for the follow-up assessment after the 5-year period. Despite the association between mood disorders and significant functioning impairment, the researchers found improvement in functioning between the two assessments when only time was considered.

According to the study, 76% of MDD participants were in a depressive episode at the first assessment compared to 32% after 5 years. Additionally, of the participants with bipolar disorder, 60% were in a depressive episode, and 20% were in a manic or hypomanic episode at the beginning of the study, dropping to 29% and 12%, respectively, at the second check-in.

Lower FAST scores were associated with functional improvements at the end of the 5-year period in both the major depression and bipolar disorder groups, (P = .012 and P = .009 respectively). The control group however, showed no functional improvement at the end of the 5-year period (P = .926), according to the study. The researchers noted that depression severity was not significantly different in those suffering depressive episodes at the follow-up assessment, but that depressive episodes had a significant interaction with time in patients with bipolar disorder, demonstrating a worsening of disability at follow-up regardless of diagnosis. Contrary to the initial hypothesis, euthymia was not associated with more functional impairment in participants with mood disorders.

“Individuals in euthymia may even improve their functioning, as our data indicate, but relapsing or sustaining depressive symptoms often results in further functional impairments,” Farias and colleagues wrote. “These findings should be taken into consideration to reinforce early intervention proposals.”