Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and impulsivity that begins in childhood and can persist into adulthood. The mainstay of treatment for ADHD is stimulant medication, which is thought to work by increasing the brain’s ability to focus and pay attention. Stimulants like methylphenidate (Ritalin) and amphetamine salts (Adderall) help regulate key chemicals in the brain and nerves that are implicated in ADHD symptoms. So what exactly happens when someone with ADHD takes one of these stimulant medications?
How do stimulants work in the brain?
Stimulants work primarily by increasing the amount of dopamine and norepinephrine available in the brain. Specifically, they block their reabsorption, causing a buildup of these chemicals between neurons. Dopamine and norepinephrine are neurotransmitters that play important roles in executive functioning of the brain, which controls abilities like attention, concentration, memory, motivation and impulse control. People with ADHD are thought to have imbalances or deficiencies in dopamine and norepinephrine compared to those without ADHD. By increasing the availability of these chemicals in the brain, stimulants can improve communication between brain cells and lead to better focus and task completion.
Immediate effects
Stimulants typically begin working within 30 to 60 minutes of being taken. Effects are often felt quickly and can last for 4-12 hours, depending on the formulation. The immediate effects of stimulants in people with ADHD include:
- Improved concentration and focus – Ability to pay attention is enhanced.
- Increased attention span – They can focus for longer periods of time.
- Improved motivation – They feel more motivated to complete tasks.
- Decreased distractibility – Easier to ignore distractions and interruptions.
- Reduced hyperactivity – Excess motor activity is calmed.
- Improved memory – Recall and attention to detail is enhanced.
- More energy and alertness – Feel more awake and attentive.
- Improved organization – They can plan and arrange tasks more efficiently.
Many report feeling like their mind has “woken up” and they are able to think clearly and sit still to concentrate after taking stimulants. The effects help counteract the ADHD symptoms of inattention, hyperactivity and impulsivity.
How stimulants affect the brain
Research utilizing brain imaging technology has shown that stimulants cause several measurable changes in brain activity for those with ADHD:
- Increased activity in the prefrontal cortex – The area of the brain responsible for executive functioning shows improved activation and blood flow after a dose of stimulants in people with ADHD. This is the part of the brain involved with organization, planning, focus and impulse control.
- Calming of the basal ganglia – Hyperactivity in this region of the brain is associated with ADHD and is dampened when taking stimulants.
- Increased dopamine transmission – PET scans show stimulants facilitate the release and prevent the reuptake of the neurotransmitter dopamine, increasing its level and activity between neurons.
- Increased norepinephrine – Stimulants similarly boost levels of norepinephrine, which also aids concentration, attention and memory.
- Normalized glucose metabolism – Abnormal glucose uptake in certain brain regions appears to be normalized by stimulants in those with ADHD.
This evidence demonstrates that stimulants trigger specific changes in neurotransmitter levels and associated energy use that lessen ADHD symptoms.
Effects on executive functioning
Numerous studies have shown that stimulants improve various aspects of executive functioning in those with ADHD. Executive functions are cognitive processes that regulate thoughts and behaviors. Components of executive functioning that are enhanced by stimulant medication include:
- Impulse control
- Focus and sustained attention
- Organization and planning
- Working memory
- Self-monitoring
- Emotional regulation
These changes in executive abilities underlie improved concentration, decreased hyperactivity, better memory and increased ability to complete tasks.
Impact on dopamine and motivation
In addition to cognitive enhancement, some research suggests stimulants may alter motivation levels in those with ADHD. Brain imaging studies hint that abnormalities in dopamine pathways may be at play. Dopamine not only regulates attention and focus, but also plays a key role in motivation and reward-seeking behavior.
Stimulants may work to normalize deficient dopamine signaling linked to motivation. There is some evidence they can enhance task saliency and make work seem more rewarding. This may partially explain observations of increased motivation and persistence in completing tasks when taking stimulants.
Effect on energy levels
Many people with ADHD report feeling more energetic and awake after taking stimulant medication. There are a few reasons stimulants may increase energy:
- Activation of the central nervous system – Stimulants stimulate the central nervous system, just like caffeine does. This temporary stimulation can cause a feeling of increased energy and alertness.
- Dopamine effects – By increasing dopamine levels, stimulants may replicate their activating and energizing effects.
- Improved focus – Allowing greater focus can translate to feeling more awake. Some hypothesize that inattentiveness may actually create a sensation of fatigue.
However, stimulants likely won’t create energy not already there. They don’t remove the need for adequate sleep and rest. But they can help combat symptoms of fatigue and low energy associated with challenges in sustaining focus and effort that are common in ADHD.
Physical effects
In addition to cognitive and energetic effects, stimulants also exert several physical changes:
- Appetite reduction – Stimulants commonly lead to decreased appetite and weight loss.
- Improved fine motor coordination – Ability to perform physical tasks requiring coordination is enhanced.
- Increased blood pressure and heart rate – Stimulants activate the sympathetic nervous system, causing a modest increase in blood pressure and resting pulse.
- Dilation of bronchial passages – Opening airways slightly can benefit those with asthma.
- Increased body temperature – Core body temp may raise slightly.
- Headaches – Vasoconstriction caused by stimulants can sometimes trigger headaches.
- Digestive issues – Some experience nausea, stomach pain or constipation from stimulants.
These types of physiological effects vary between individuals but are worth noting. Be sure to let your doctor know if any worrisome side effects occur.
Response in those without ADHD
It’s important to understand that stimulants affect those with and without ADHD very differently. In people who don’t have ADHD, stimulants usually cause over-stimulation, resulting in:
- Jitteriness, nervousness and anxiety
- Rapid speech
- Insomnia
- Fast heart rate and increase in blood pressure
- Sweating
- Headaches
- Euphoria and a “high” at certain dosages
Because of this potential for misuse, stimulant medications are classified as controlled substances with strict regulations on prescribing and dispensing. Their paradoxical calming and performance-enhancing effects seem unique to those with ADHD.
Long-term benefits
The benefits of stimulants are not limited to the hours they are acting. Research shows that, with continued use, stimulants can produce lasting improvements in those with ADHD:
- Better school and work performance – Grades and productivity tend to improve.
- Increase in focused activities – More time is spent engaged in tasks instead of being distracted.
- Improved driving ability – Fewer instances of speeding and accidents are reported.
- Decreased rule breaking and criminal behaviors – Less impulsivity translates to staying out of trouble.
- Reduced substance abuse – Having ADHD raises the risk of drug abuse. Stimulants may lower rates of smoking, drinking and illicit drug use.
- More social engagement – Interacting with peers improves, possibly due to an increased ability to focus during conversation.
While the immediate effects wear off as the medication leaves the body, persisting benefits continue to build through ongoing treatment. However, stimulants are most effective when combined with behavioral interventions and lifestyle changes.
Are there downsides?
Stimulants provide significant benefits for most people with ADHD, but some potential downsides do exist:
- Disruptions in sleep – Stimulants may cause insomnia, especially if taken too late in the day.
- Appetite loss – Medication can lead to temporary loss of appetite and weight loss.
- Growth suppression – Children may experience slower growth rates.
- Mood swings – Some report irritability or depressive symptoms as medication wears off.
- Headaches – Stimulant medications commonly produce headaches in some users.
- Rebound effects – Hyperactivity or loss of focus may temporarily worsen as the stimulant leaves the body.
- Diversion for misuse – These controlled substances carry a risk of abuse and diversion by those without ADHD.
Under a doctor’s supervision, adverse effects can usually be managed by adjusting the medication dosage or formulation. Tolerance to side effects also often develops over time. But stimulants are not for everyone, and other non-stimulant medications may be considered.
Risk of abuse and addiction
There are common misconceptions that stimulant medications used to treat ADHD share a high risk of abuse and addiction. However, studies show that actual rates of misuse are relatively low when stimulant medications are prescribed appropriately:
- Less than 5% of children and adolescents with ADHD abuse their prescribed stimulants.
- About 5-10% of college students misuse stimulant medications, using diverted pills to aid studying.
- Only about 1 in 400 patients misuse their stimulant prescriptions.
- Rates of actual dependence are very rare, affecting an estimated 1 in 550 patients with ADHD taking stimulants.
While the chance exists, good prescribing practices, patient monitoring and education greatly limit problems. For people with ADHD, stimulants at therapeutic doses do not tend to create a “high” or euphoria like those seeking recreational use.
Proper dosing is key
Stimulants are very effective when dosed properly for an individual’s needs. However, both under and overdosing can cause problems:
Low Doses
- May provide limited help for ADHD symptoms
- Less improvement in focus, attention and hyperactivity
- School and work performance may still suffer
High Doses
- Can cause anxiety, irritability, jitteriness
- Trouble sleeping and loss of appetite
- Increase side effects like headaches and stomachaches
- Potentially increases risk of abuse and addiction
Finding the “Goldilocks” dose that provides optimal benefits with minimal side effects is key. Doctors adjust doses and timing over time for best results. Patience is required to attain the full benefits.
Use in children and adolescents
While stimulants are widely used and effective in children and teens with ADHD, their developing brains may have enhanced sensitivity:
- Dosing is started low and increased more slowly.
- Smaller body size means side effects are noticed sooner.
- Higher drug clearance results in shorter duration of benefits.
- Rebound activation can be more prominent as medication wears off.
- Good sleep and nutrition help counteract reduced appetite and weight loss.
- Growth rate and weight gain monitoring assures proper development.
Doctors remain vigilant for any concerning effects, but decades of experience support overall safety and efficacy in youth when used carefully.
Stimulant medications prescribed for ADHD
There are a variety of stimulant medications used to treat ADHD. Commonly prescribed options include:
Methylphenidate
- Ritalin, Concerta, Daytrana patch, Quillivant XR, Metadate CD
- Act for 4-6 hours (short acting) or 8-12 hours (long acting formulations)
- Available in tablet, patch, capsule and liquid forms
Amphetamine
- Adderall, Adderall XR, Evekeo, Mydayis, Vyvanse
- Act for 4-6 hours (short acting) or 8-14 hours (long acting formulations)
- Available in tablet, capsule and chewable tablet forms
Methamphetamine
*(limited use)
- Desoxyn
- Acts for 4-6 hours
- Available as tablet
Other Stimulants
- Dexedrine, Procentra, Zenzedi
- Imidacloprid, modafinil
The most commonly used prescriptions are extended release versions of methylphenidate and amphetamine. These provide long-lasting symptom relief. Your doctor will help decide which is most appropriate.
Non-stimulant options
While stimulants are the first line medication for ADHD, non-stimulant options are also available:
- Atomoxetine (Strattera)
- Guanfacine (Intuniv) and clonidine (Kapvay)
- Bupropion (Wellbutrin)
- Tricyclic antidepressants, like imipramine (Tofranil)
These target norepinephrine and dopamine through different pathways. They may be considered if stimulants cause intolerable side effects or are ineffective. However, more research needs to confirm their efficacy.
Lifestyle changes and therapies
Medication alone is usually not sufficient as a treatment for ADHD. Lifestyle modifications and behavioral therapies to help organizational, social and coping skills are key:
- Counseling and cognitive behavioral therapy
- Education plans and classroom accommodations
- Parent training and support groups
- Schedules, routines and environmental adaptation
- Skills coaching and behavioral interventions
Combining stimulant medication with these additional therapies results in the best outcomes in minimizing the impact of ADHD.
Conclusion
Stimulant medications like Ritalin and Adderall are the most common and effective pharmacological treatment for ADHD. In the brain, stimulants increase dopamine and norepinephrine levels, which strengthen signals between neurons that are impaired in ADHD. This results in enhanced ability to focus, decreased impulsivity and hyperactivity, improved memory and motivation.
Those with ADHD report feeling more attentive, calm, focused and clear-headed within an hour of taking stimulants. Brain scans confirm stimulants normalize activity in brain regions lacking in ADHD. Not only do stimulants provide immediate symptom relief, but ongoing treatment is associated with better academic and work performance, social skills and long-term outlook.
While proper medication can be life changing, stimulants must be carefully dosed for each individual. Their use also needs monitoring for side effects and supplemented with teaching healthy habits and coping skills. But when medication is combined with lifestyle changes, therapy and adjustments, stimulants can be tremendously helpful in managing ADHD challenges.