Does depression lead to influenza? - A systematic literature analysis

Area of Science:

• Immunology
• Psychiatry
• Epidemiology

Background:

• Depression affects millions annually, while influenza causes significant morbidity and mortality.
• A hypothesis suggests depressive symptoms may impair immune function, but in vivo evidence is scarce.
• Understanding the link between depression and influenza is crucial for public health.

Purpose of the Study:

• To systematically review existing literature for a correlation between depression and influenza infection.
• To assess the current scientific evidence regarding the impact of depression on influenza susceptibility.

Main Methods:

• A comprehensive literature search was conducted across major databases (PsycINFO, MEDLINE, IPA, EMBASE).
• Search terms included "influenza" and "depression" and their derivations.
• Inclusion criteria required articles to be in English and involve human subjects.

Main Results:

• The search initially identified 799 unique articles; 10 met the inclusion criteria after review.
• A significant majority (70%) of the evaluated studies found no difference in hemagglutinin levels between depressed and non-depressed individuals.
• Limited scientific evidence was found to support a direct correlation.

Conclusions:

• This systematic review is the first to specifically examine the correlation between influenza infection and depression.
• The current body of scientific evidence is insufficient to establish a definitive link or determine influenza risk in patients with depression.
• Further research is warranted to explore this potential relationship.