Duration of undiagnosed bipolar disorder unrelated to treatment response

By Joanna Lyford, Senior medwireNews Reporter

The duration of undiagnosed bipolar disorder is unrelated to patients’ clinical status or their response to mood-stabilising medication, study findings indicate.

In two independent cohorts of patients with a first-time diagnosis of bipolar disorder, people with a longer duration of undiagnosed bipolar disorder and those with more severe disease at baseline had a similar or greater response to treatment than others, and within a timeframe of just 3 months or less.

“[T]here was no strong evidence that the benefit of taking mood stabilising medication in newly diagnosed [bipolar disorder] patients can vary as a function of the [duration of undiagnosed bipolar disorder]”, write Stacey McCraw (Black Dog Institute, Prince of Wales Hospital, Sydney, Australia) and co-authors in the Journal of Affective Disorders.

In the first of two studies, the team performed a cross-sectional analysis of 173 patients newly diagnosed with bipolar disorder who had a mean duration of undiagnosed bipolar disorder of 18.0 years.

The duration of undiagnosed bipolar disorder significantly correlated with age, scores on the Perceived Social Support scale and Friendship Scale, total number of lifetime stressors, number of paid jobs, longest job held, perfectionism score, social avoidance score and personal reserve score.

However, it did not correlate with disease severity measures such as number of hospitalisations and days spent in hospital, or estimated proportion of life spent in a mood episode.

In the second study, McCraw et al assessed 64 patients with newly diagnosed bipolar disorder and a mean duration of undiagnosed bipolar disorder of 19.9 years. Patients were evaluated at baseline and again after 3 months of treatment.

At 3 months, 80% of patients said they considered their medication to be moderately or extremely effective and 70% had noted a moderate to significant improvement in their mood symptoms. Clinicians’ independent assessments were in line with the patient reports.

There was no correlation between duration of undiagnosed bipolar disorder and the degree of change in mood symptoms, overall functioning or benefit of medication, report the authors; however, more severe depression or poorer functioning at baseline predicted a greater magnitude of treatment benefit over 3 months.

“Thus, consistent with our hypotheses, the majority of participants improved following the introduction of disorder-specific treatment, and [duration of undiagnosed bipolar disorder] was not able to discriminate between the likelihood of ‘improvement’ versus ‘no improvement’ status”, the team concludes.

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