A chronic deficit of serotonin (5-HT) at the synapse may trigger symptoms of ADHD.
People with ADHD have at least one defective gene, the DRD2 gene that makes it difficult for neurons to respond to dopamine, the neurotransmitter that is involved in feelings of pleasure and the regulation of attention.
Abstract. Recent research has suggested that serotonin, in addition to dopamine, may be involved in the development of attention deficit hyperactivity disorder (ADHD). Serotonin regulates dopaminergic neurotransmission in some areas of the brain via several 5-HT receptors including 5-HT1B.
Causes of ADHD
Recent studies link genetic factors with ADHD. In addition to genetics, scientists are studying other possible causes and risk factors including: Brain injury. Exposure to environmental risks (e.g., lead) during pregnancy or at a young age.
ADHD brains have low levels of a neurotransmitter called norepinephrine. Norepinephrine is linked arm-in-arm with dopamine. Dopamine is the thing that helps control the brain's reward and pleasure center.
If your child has ADHD, they may be low in dopamine but high in something called dopamine transporters. That's because their low dopamine may actually result from having too many of the transporters that take dopamine out of their brain cells.
Indeed, ADHD brains struggle to sustain motivation when rewards are mild or are linked to long-term gratification. As a result, ADHD brains search for stimulation that can increase dopamine more quickly and intensely. Ultimately, the pursuit of pleasurable rewards may become a potent form of self-medication.
Differences Between an ADHD Brain and a Non-ADHD Brain
Since the two go hand-in-hand, experts believe that lower levels of dopamine and norepinephrine are both linked to ADHD. An imbalance in the transmission of dopamine in the brain may be associated with symptoms of ADHD, including inattention and impulsivity.
Genetics. ADHD tends to run in families and, in most cases, it's thought the genes you inherit from your parents are a significant factor in developing the condition. Research shows that parents and siblings of someone with ADHD are more likely to have ADHD themselves.
While there's no known specific cause for ADHD, varying dopamine levels, norepinephrine, and serotonin in the brain can contribute to the severity of its symptoms.
Some inherited genetic disorders may affect the body's ability to make or metabolize serotonin. Lifestyle and other factors that may also play a role include: Hormonal shifts, such as due to beginning or stopping hormone replacement therapy, menopause, pregnancy, or advancing age. Lack of sunlight.
The ADHD brain has been described as an “interest-based nervous system”: It seeks high-stimulation situations, stronger incentives, and more immediate rewards, which trigger a quick and intense release of dopamine and with it a rush of motivation. Hyperfocus. Dopamine is the brain's most intense reward.
Executive functions have other roles which affect how someone thinks. In people with ADHD, these executive dysfunctions impact thinking in numerous ways. People with ADHD don't really think faster than people without it, but it can sometimes seem like they do. People with ADHD do think differently though, in a sense.
Stimulant medications that treat ADHD can prevent the reuptake of dopamine, increasing brain levels of the chemical. Lifestyle changes can also help, especially in conjunction with standard ADHD treatments. Exercise, a healthy diet, and therapy all offer potential benefits.
Adults with ADHD may find it difficult to focus and prioritize, leading to missed deadlines and forgotten meetings or social plans. The inability to control impulses can range from impatience waiting in line or driving in traffic to mood swings and outbursts of anger. Adult ADHD symptoms may include: Impulsiveness.
Attention-deficit/hyperactivity disorder (ADHD) is one of the most common mental disorders affecting children. Symptoms of ADHD include inattention (not being able to keep focus), hyperactivity (excess movement that is not fitting to the setting) and impulsivity (hasty acts that occur in the moment without thought).
Boys have a big boost in testosterone, and girls see a rise in estradiol, a type of estrogen. These changes in hormone levels can have important effects on kids with ADHD. For example, high levels of testosterone can affect brain circuits in a way that causes more symptoms of the condition.
Due to this lack of dopamine, people with ADHD are "chemically wired" to seek more, says John Ratey, M.D., professor of psychiatry at Harvard Medical School in Boston. "Eating carbohydrates triggers a rush of dopamine in the brain," he says. "It's the drive for the feeling of satiety."
Executive attention is your ability to filter out distracting or extraneous material from your awareness. ADHD brains don't love this to begin with- it takes a lot of its energy- lack of sleep depletes the resource so significantly it can feel like the filter never even existed.
Some signs that you might be understimulated include: Lack of motivation. Physical hyperactivity. A sense of unease, making you feel "flat" or irritable.
Low dopamine symptoms can include a lack of enthusiasm for things you usually enjoy and are interested in. Plus, having low dopamine may have a low sex drive. You may also experience physical troubles such as insomnia, tremors, muscle spasms, stiffness, and difficulty moving.