Prodromal Symptoms in Depression: A Systematic Review

Area of Science:

• Psychiatry and Behavioral Sciences
• Clinical Psychology
• Neuroscience

Background:

• Understanding prodromal symptoms of unipolar depression offers a longitudinal perspective beyond traditional cross-sectional approaches.
• A staging model of unipolar depression highlights the importance of identifying early, pre-onset symptoms.

Purpose of the Study:

• To conduct an updated systematic review of clinical studies on prodromal symptoms of unipolar depression.
• To adhere to PRISMA guidelines for a comprehensive and transparent review process.

Main Methods:

• Systematic literature search across PubMed, Scopus, and Web of Science databases.
• Inclusion of longitudinal studies focusing on prodromal symptoms and signs in adults with primary unipolar depression diagnosis.
• Analysis of findings categorized by study design: retrospective and prospective.

Main Results:

• Twenty-five studies were included, confirming a distinct prodromal symptomatology preceding unipolar depression.
• Common prodromal symptoms include anxiety, tension, irritability, and somatic complaints.
• The duration of the prodromal phase varied significantly (less than a month to several years) but was consistent within individuals across episodes, showing a link to residual symptoms.

Conclusions:

• The study addresses the under-researched area of prodromal depression, offering practical clinical value.
• Findings provide insights into depression's pathogenesis and course, potentially leading to earlier and more effective recurrence treatment.
• Defining the prodromal phase requires integrating symptom identification, biomarkers, and neuroimaging.