Certain substances cause pupils to expand dramatically, serving as a visible clue to recent drug use. When examining which drugs make your pupils large, stimulants like cocaine and meth (methamphetamine) consistently trigger this reaction by overstimulating the nervous system. Hallucinogens such as LSD and psilocybin mushrooms can also cause pronounced dilation by altering brain chemistry and sensory perception. Even some prescription medications can produce this effect as an unexpected side effect.
Understanding these physical signs can provide valuable insight into potential substance use. While dilated pupils don’t automatically indicate drug abuse, recognizing this symptom can help start important conversations.
Stimulant Drugs Known to Enlarge Pupils
Certain stimulant drugs can cause your pupils to dilate, a condition known as mydriasis. This occurs due to the drugs’ effects on the sympathetic nervous system, leading to increased levels of neurotransmitters like dopamine and norepinephrine.
Here are some examples of stimulants that can cause pupil dilation:
Cocaine
A powerful stimulant that blocks the reuptake of dopamine, norepinephrine, and serotonin, leading to increased levels of these neurotransmitters in the brain. This action stimulates the sympathetic nervous system, resulting in dilated pupils.
Methamphetamine (crystal meth)
A potent stimulant that increases the release of dopamine and norepinephrine. This surge in neurotransmitters leads to heightened alertness and energy, along with pupil dilation.
MDMA (ecstasy/molly)
A synthetic drug that functions as both a stimulant and a hallucinogen. It both increases the release of and blocks the reuptake of serotonin, norepinephrine, and dopamine. This can lead to enhanced mood, energy, and pupil dilation.
Adderall (amphetamine/sextroamphetamine)
A prescription medication used for treating ADHD and narcolepsy. It increases the levels of norepinephrine and dopamine in the brain, which can cause pupil dilation as a side effect.
Ritalin
Similar to Adderall, Ritalin is used to treat ADHD. It works by blocking the reuptake of dopamine in the brain, potentially leading to dilated pupils.
Bath Salts (synthetic cathinones)
A category of synthetic drugs that are chemically related to amphetamines. They can cause severe agitation, hallucinations, and pupil dilation due to their stimulant effects.
Ephedrine
A sympathomimetic drug that stimulates the release of and blocks reuptake of norepinephrine. It can cause pupil dilation by activating adrenergic receptors in the iris.
Pseudoephedrine
Commonly found in over-the-counter decongestants, pseudoephedrine can stimulate the release of norepinephrine. This can lead to pupil dilation.
Hallucinogens that Influence Pupil Size
Hallucinogens, such as LSD, psilocybin (found in magic mushrooms), and mescaline, can cause your pupils to dilate. This dilation is typically temporary and subsides as the effects of the drug wear off.
Natural Substances that Affect Pupil Size
Belladonna, also known as deadly nightshade, contains atropine, a compound that dilates pupils by blocking the parasympathetic nervous system’s signals to the eye muscles. This action prevents the pupil from constricting, resulting in noticeable enlargement.
Historically, belladonna was used in Italy to dilate pupils for cosmetic purposes. Today, atropine derived from belladonna is utilized in ophthalmology to dilate pupils during eye examinations and surgeries .
Anticholinergic Agents that Affect Pupil Dilation
Certain medications work by affecting specific receptors in the eyes, particularly one called M3 that is very important for how the eye muscles function. By antagonizing these receptors, anticholinergic drugs not only dilate the pupil but can also relax the ciliary muscle, affecting the eye’s ability to focus on nearby objects. This dual action is beneficial during eye examinations and certain surgical procedures.
Anticholinergic agents cause pupil dilation by blocking acetylcholine, a neurotransmitter responsible for activating the iris sphincter muscle. Medications like atropine and cyclopentolate are commonly used in ophthalmology to dilate pupils.
When Should Dilated Pupils Prompt Medical Attention?
Dilated pupils can be a normal response to changes in light or emotional stimuli. However, if pupils remain dilated without a clear cause, it’s important to seek medical attention.
Persistent dilation may indicate underlying issues such as neurological disorders, head trauma, or adverse reactions to medications or drugs. Certain recreational substances, including LSD, MDMA, and methamphetamines, can cause pupil dilation. Additionally, medications like antihistamines, antidepressants, and anti-nausea drugs may also lead to dilated pupils. This is not always an indicator that something has gone wrong. But it should be considered in considering the person’s overall health.
If you experience symptoms like blurred vision, sensitivity to light, headaches, dizziness, confusion, or if one pupil is larger than the other, it’s crucial to consult a healthcare provider promptly. These could be signs of serious conditions such as stroke, brain injury, or other neurological issues. Seeking immediate medical care is recommended in these situations to prevent lasting damage.
Is Pupil Dilation a Reliable Indicator of Drug Use?
Pupil dilation can be a sign of drug use, but it’s not always reliable. Certain substances, like stimulants (e.g., amphetamines, cocaine) and hallucinogens (e.g., LSD, MDMA), are known to cause pupils to dilate. However, other factors such as lighting conditions, emotional states, and medical conditions can also influence pupil size.
While dilated pupils can be an indicator of recent drug use, they should not be solely relied upon to determine drug use. Recent drug use also does not always indicate that that person is addicted to drugs they have used recently. It’s more important to consider them as one potential sign that is taken into account with others that say more about the person’s overall life and habits.
What are Common Signs of Drug Addiction?
While pupil dilation can be a physical indicator of addiction, it’s important to consider a combination of behavioral, physical, and psychological symptoms.
Behavioral Signs of Addiction
- Neglecting responsibilities at work, school, or home
- Engaging in secretive or suspicious behavior
- Acting defensive when drug use is questioned
- Sudden changes in friends, favorite hangout spots, or hobbies
- Unexplained need to borrow money or financial problems
- Withdrawal from social engagements
- Experiencing legal issues, such as arrests for disorderly conduct, DUI, or theft
Physical Signs of Addiction
- Bloodshot eyes, or pupils are larger (or smaller) than usual more frequently
- Changes in appetite
- Disturbed sleep or altered sleeping patterns
- Sudden weight loss or gain
- Deterioration of physical appearance and/or personal grooming habits
- Unusual smells on breath, body, or clothing
- Tremors
- Slurred or suddenly rapid speech
- Impaired coordination
- Withdrawal symptoms, such as shaking hands or physical cravings
Psychological Signs of Addiction
- Unexplained change in personality or attitude
- Sudden mood swings or angry outbursts
- Irritability
- Lethargy
- Periods of unusual hyperactivity, agitation, or giddiness
- Lack of motivation
- Shows signs of anxiety, fear, or paranoia without apparent cause
It’s important to remember that no one drug causes every person to behave the same. But there are patterns, and people in a person’s life can be observant and track changes over time in deciding how to confront the person about their drug use.
Get Help For Addiction At First Steps Recovery
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You don’t have to worry about addiction taking over your life and body. We at First Steps Recovery are here to help support your journey to recovery and help you heal in a holistic way. To learn more or begin the admission process, contact us today.
Dr. Curl is the Medical Director and primary on-site provider for First Steps Recovery. He is a Board Certified Internist and Addiction Medicine Specialist having attended the David Geffen School of Medicine at UCLA and completing his residency at Mount Auburn Hospital with Harvard Medical School. Following several years work as an internist and physiatrist (physical medicine and rehabilitation). Dr. Curl completed the Addiction Medicine Fellowship at Howard University in Washington DC and participated as a RAM Scholar (Research in Addiction Medicine). While part of the fellowship, Dr. Curl pursued research investigating the barriers to expanding and improving medication for opioid use disorder. Following his fellowship, Dr. Curl spearheaded the Opiate Use Disorder outpatient clinic and worked in the Department of Psychiatry and Behavioral Sciences within the Howard University Hospital. In 2023, Dr. Curl completed his Board Certification in Addiction Medicine.
