What Drugs Cause Dilated Pupils?

The signs of drug use can sometimes include changes in a person’s eyes. What drugs cause dilated pupils, and why do they have this effect?

Learn more about our addiction treatment in Northern California or verify your insurance now.

Why Do Drugs Affect Your Pupils?

Before we talk about what drugs cause dilated pupils, let’s first look at why certain substances have this effect.

Normally, your pupils (the dark spots in the center of your eyes) will increase or decrease in size to maintain your vision various lighting conditions. When you’re in a brightly lit area, your pupils will contract, or get smaller, to limit the amount of light that reaches the retina. In darker environments, your pupils will expand to let in more light.

Some drugs can also cause changes in pupil size due to their impact on your autonomic nervous system. The two primary parts of this system are:

• The sympathetic nervous system, which triggers the body’s “fight or flight” response to perceived dangers
• The parasympathetic nervous system, which controls “rest and digest” functions 

Drugs that stimulate the sympathetic nervous system cause dilated (enlarged) pupils, which would naturally occur to enhance vision when facing an imminent threat. Drugs that block the sympathetic nervous system or stimulate the parasympathetic system can have the opposite effect, causing pinpoint (constricted) pupils. 

What Drugs Cause Dilated Pupils?

The clinical term for dilated or expanded pupils is mydriasis. Drugs that can have this effect include:

• Stimulants such as cocaine (both powder and crack), amphetamine, and methamphetamine (crystal meth)
• Opioids such as heroin, morphine, fentanyl, and many prescription painkillers
• Hallucinogens including LSD, psilocybin (magic mushrooms or shrooms), and DMT

Some other substances, such as certain prescription medications, can also cause dilated pupils. Before you start to take any prescription drug, you should always talk to your doctor or pharmacist to ensure that you’re aware of any potential side effects, including dilated pupils.

Other Signs of Drug Use

In addition to altering the size of a person’s pupils, both legal and illicit drugs can also cause a range of noticeable physical and psychological changes. Factors that can influence the type and severity of these changes include:

• Which kind of drug a person used
• How much of the drug they took
• If they have any physical or mental health concerns

Below, we’ll look at the effects of two common categories of drugs, stimulants and depressants.

Stimulants

Stimulants are substances that trigger increased activity within the central nervous system (CNS), which delivers messages between the brain and other parts of the body. This category includes legal drugs such as caffeine and nicotine, prescription medications such as Adderall and Ritalin, and illicit drugs such as cocaine, crack, and meth.

Physical signs of stimulant use can include:

• Excessive perspiration
• Elevated heart rate
• Rapid breathing
• High energy level
• Increased talkativeness
• Heightened libido
• Minimal need for sleep

Psychological effects of stimulants can include:

• Improved confidence
• Racing thoughts
• Impulsivity
• Anxiety
• Panic
• Paranoia

Depressants

Depressants have the opposite effect on the CNS. Instead of speeding the delivery of messages between the brain and other body parts, they cause a slowdown in CNS functioning. 

Examples of commonly used depressants include opioids, alcohol, and benzodiazepines.

Somone who has been using a depressant may have physical symptoms such as:

• Easing of pain
• Slowed heart rate and breathing
• Delayed physical responsiveness
• Poor balance and coordination
• Difficulty staying awake

The psychological impact of depressant use can include:

• Improved mood
• Altered perceptions of time and space
• Delayed reaction time
• Confusion and disorientation
• Memory problems

Addiction Warning Signs

The signs above can indicate that a person is currently under the influence of a drug, but they can’t necessarily indicate if a person has become dependent on the drug. 

Once a person’s substance use crosses the line from a choice to a compulsion, they may begin to exhibit a range of additional physical, psychological, and behavioral warning signs, such as:

• Using substances in larger amounts or for longer periods of time than they intended
• Neglecting to pay bills, missing appointments, and failing to meet other obligations because of their drug use
• Continuing to use drugs even after they’ve had physical, psychological, or social problems that were either caused or worsened by their prior use
• Exhibiting significant changes in mood, attitude, and energy
• Having unexplained financial problems
• Neglecting their appearance
• Unintentionally gaining or losing weight
• Withdrawing from family and friends
• Being secretive or deceptive about their activities and whereabouts
• Lying about the amount and frequency of their drug use
• Trying to buy, borrow, or steal medications that were prescribed to someone else
• Reducing or ending their participation in important social or work-related activities
• Using drugs in ways that pose a clear physical danger, such as by combining multiple substances or driving while under the influence
• Developing tolerance, which means they need to use more of a substance to experience effects that they could previously achieve with smaller doses
• Having withdrawal symptoms when they attempt to curtail their drug use

If you are concerned that someone in your life has become addicted to alcohol or another drug, a good first step would be to have them assessed by their doctor or a qualified addiction expert. 

Receiving an accurate diagnosis can help them understand the scope of the challenge they’re facing, and the professional who conducts their assessment should also be able to recommend appropriate treatment options.

Find Addiction Treatment in Northern California

Bright Future Recovery offers a full continuum of personalized programming for adults who have become addicted to alcohol and other drugs. We also provide dual diagnosis services for patients whose struggles with addiction accompanied by anxiety, depression, PTSD, and other co-occurring mental health concerns.

Treatment options at our rehab in Northern California include:

• Detoxification (detox)
• Residential program
• Partial hospitalization program (PHP)
• Intensive outpatient program (IOP)
• Virtual (online) outpatient program

A member of our team will be happy to discuss the features and benefits of each of these programs with you, and help you determine which ones may be best for you or your loved one.

To learn more about our programs and services, or to schedule a free assessment, please visit our Contact page or call us today.