Neurotransmitters: Relationship to Impulsivity and Aggression
Over the past three decades, behavioral and learning disorders have evolved into chronic conditions affecting children and adolescents in the United States. Both educators and physicians are reporting an increase in the number of children with these disorders. Of these disorders, Attention Deficit/Hyperactivity Disorder (AD/HD) is steadily increasing in prevalence.
The number of special education programs for children suffering from AD/HD has expanded in the last decades. Additionally, a marked increase in the use of prescription medications has also been observed for children and adults suffering from AD/HD.
According to the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) AD/HD is a mental disorder characterized by "a persistent pattern of inattention and/or hyperactivity-impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development.
DSM-IV Criteria for ADHD
Six or more of the following symptoms of inattention have been present for at least 6 months to a point that is disruptive and inappropriate for developmental level:
- 1. Often does not give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
- Often has trouble keeping attention on tasks or play activities.
- Often does not seem to listen when spoken to directly.
- Often does not follow instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions).
- Often has trouble organizing activities.
- Often avoids, dislikes, or doesn't want to do things that take a lot of mental effort for a long period of time (such as schoolwork or homework).
- Often loses things needed for tasks and activities (e.g. toys, school assignments, pencils, books, or tools).
- Is often easily distracted.
- Is often forgetful in daily activities.
Six or more of the following symptoms of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for developmental level:
- Often fidgets with hands or feet or squirms in seat.
- Often gets up from seat when remaining in seat is expected.
- Often runs about or climbs when and where it is not appropriate (adolescents or adults may feel very restless).
- Often has trouble playing or enjoying leisure activities quietly.
- Is often "on the go" or often acts as if "driven by a motor".
- Often talks excessively.
- Often blurts out answers before questions have been finished.
- Often has trouble waiting one's turn.
- Often interrupts or intrudes on others (e.g., butts into conversations or games).
Individuals diagnosed with ADHD share similarities among behavioral symptoms. However, the underlying causes may be heterogeneous due to a combination of several, biological, psychological and social factors.
Additionally, research has indicated that several biochemical factors may play a role in AD/HD. This includes food allergies and sensitivity to food additives such as flavor enhancers, coloring agents, as well as preservatives. Heavy metal toxicities (aluminum, lead, mercury) and other environmental toxins from air, food and water, vitamin deficiencies (B1, B3, B6), mineral (iron, selenium, zinc, copper, calcium, magnesium) and amino acid (tryptophan, tyrosine, phenylalanine) abnormalities, essential fatty acids (omega-3 series) and phospholipid deficiencies, thyroid disorders as well as genetic predisposition can all play a role in AD/HD.
AD/HD has been associated with deficiencies in the neurotransmitters Norepinephrine and Epinephrine. Both of these neurotransmitters are involved in cognitive function. As such, the prescription medication commonly used for AD/HD (Ritalin) is thought to provide a stimulating effect in the Central Nervous System resulting in increased release of the neurotransmitters Norepinephrine and Dopamine.