Cognitive mechanisms underlying depressive disorders in ADHD: A systematic review

Area of Science:

• Neuroscience
• Psychiatry
• Developmental Psychology

Background:

• Attention-deficit/hyperactivity disorder (ADHD) significantly increases the risk of major depressive disorder (MDD) in young adults.
• The neurobiological mechanisms underlying this comorbidity are not well understood.

Purpose of the Study:

• To explore ADHD-specific neurocognitive impairments as potential mechanisms linking ADHD and MDD.
• To identify pre-existing risk markers for depression in individuals with ADHD.

Main Methods:

• Systematic literature searches were conducted in EBSCOhost, PubMed, and Cochrane Reviews following PRISMA guidelines.
• Two searches focused on cognitive dysfunctions in MDD and reaction time variability in MDD, analyzing meta-analyses and original studies.

Main Results:

• Cognitive deficits observed during acute depression overlap with some ADHD-related impairments.
• Executive dysfunctions (selective attention, verbal fluency, working memory) and long-term memory issues appear to be shared impairments.
• These shared deficits may represent pre-existing risk markers for depression.

Conclusions:

• Specific neurocognitive mechanisms, particularly executive functions and memory, may mediate developmental pathways from ADHD to MDD.
• These findings could inform future depression prevention strategies for individuals with ADHD.