Verbal fluency in bipolar disorders: A systematic review and meta-analysis

Area of Science:

• Psycholinguistics
• Neuroscience
• Clinical Psychology

Background:

• Bipolar disorder (BD) is characterized by mood dysregulation and language alterations.
• Patients with BD exhibit changes in semantic content, verbal associations, prosody, and speech speed.
• Verbal fluency tasks are commonly used to assess language retrieval in BD, but results are inconsistent.

Purpose of the Study:

• To quantify the verbal fluency impairment in bipolar disorder patients.
• To investigate the influence of task type and mood state on these deficits.

Main Methods:

• A systematic literature search was performed across major databases (MEDLINE, EBSCOHost, Google Scholar).
• Data from 39 studies involving 52 independent groups of BD patients were meta-analyzed.

Main Results:

• A moderate verbal fluency impairment was observed in BD patients compared to healthy controls (d=0.61).
• Significant differences in category fluency were found between euthymic and manic patients.
• Few studies examined depressive or mixed episodes, and heterogeneity in BD populations was noted.

Conclusions:

• Bipolar disorder patients exhibit moderate verbal fluency deficits.
• Mood state significantly impacts category fluency performance in BD.
• Distinguishing semantic from phonological processes is crucial for verbal fluency assessments in BD.