Etiologic classification of attention-deficit/hyperactivity disorder

Area of Science:

• Neurobiology
• Developmental Pediatrics
• Environmental Health

Background:

• Attention-deficit/hyperactivity disorder (ADHD) is a common neurobiological syndrome affecting 5% of children and adolescents.
• While highly heritable, acquired environmental factors also play a role in ADHD etiology.
• Previous research suggests links between ADHD symptoms and brain trauma, viral encephalitis, and MRI-identified brain volumetric changes.

Purpose of the Study:

• To provide an overview of environmental factors contributing to ADHD etiology.
• To encourage increased research into organic causal factors for ADHD.
• To highlight the potential for preventive measures and specific therapies targeting environmental causes of ADHD.

Main Methods:

• Review of existing literature on environmental influences in ADHD.
• Discussion of prenatal, perinatal, and postnatal risk factors.
• Examination of childhood illnesses, toxins, drugs, and controversial factors like diet and iron deficiency.

Main Results:

• Identified prenatal risks: maternal smoking/alcohol use, prematurity, hypoxic-ischemic encephalopathy, thyroid deficiency.
• Identified perinatal/postnatal risks: viral infections, meningitis, encephalitis, head injury, epilepsy, toxins, drugs.
• Discussed controversial factors: diet sensitivities and iron deficiency as potential contributors to ADHD.

Conclusions:

• Early recognition and intervention for environmental ADHD etiologies are crucial.
• Preventing environmental causes may decrease the need for medication-based symptom management.
• Further research into organic causal factors is essential for developing targeted ADHD therapies.