Are Pupils Bigger or Smaller When Under the Influence?

Are Pupils Bigger or Smaller When Under the Influence?

If you’re looking for specific signs that someone you love is under the influence of drugs or alcohol, they may have gotten good at hiding the more obvious signs they have used. There are still some telltale indicators, however, and if you’re trying to determine the sobriety of someone, you need to understand how the body responds to the substance in question.
One of the key indicators you can look for has to do with the size of their pupils. However, if you haven’t had to deal with situations like these in the past, you may not know exactly how substances can affect the eyes. So you need to know the answer to a vital question — are pupils bigger or smaller when under the influence?

How Should Pupils React to Light While Sober?

Whether it’s alcohol, marijuana, or some other hard drug, knowing some of the key physical characteristics that show when someone has taken the substance can make a difference in their recovery. Our pupils naturally respond to the presence of light, and when you’re completely sober, they will quickly shrink when exposed to direct light. However, when you’re under the influence, the reaction time changes.

What Happens to Pupil Dilation? 

Whether it’s a few drinks or a hit of something, your body undergoes a wide range of physical, emotional, and chemical reactions—one of those deals directly with your eyes and their response to light. Everyone who has received an eye exam knows that your eye doctor will flash a light into your eyes to gauge your pupil’s response and sensitivity to light.

Under normal conditions, your eyes have a quick reaction time and retract when exposed to direct light. However, your pupils become noticeably more sluggish when you’re under the influence of drugs or alcohol. They will eventually contract like they normally would, but the response is often much slower, providing you with a clear indication of a narcotic or alcoholic substance at work.

Do Various Substances Affect Eyes Differently?

Dilated pupils may help you determine that there is a foreign substance at work, but how well does it inform you that it’s a particular substance? Do different drugs affect your pupils differently, or do your pupils respond in the same sluggish way every time?


Thanks to the ethanol in alcohol, your eyes react to it with mild to moderate symptoms. You may experience blurry vision, dilated pupils, or potential night blindness when you drink heavily. Your pupils will respond more sluggish than normal and take longer to contract when exposed to direct light. 


While your pupils may not dilate like alcohol, your vision may still experience impairments after smoking marijuana. Sometimes, you may experience mild hallucinations, visual impairment, and slower reactions. Red and glossy eyes are more likely to present as symptoms than pupil dilation. 

LSD and Mushrooms

When under the influence of hallucinogenic drugs such as LSD, mescaline, or psilocybin (mushrooms), the range of symptoms can include increased restlessness, sleep deprivation, and dilated pupils. More so than alcohol, pupil dilation has become one of the most associated physical reactions to taking “magic mushrooms.”

Get the Support You Need From a Trusted Drug Treatment Center in Mahanoy, City, PA

Whether you or someone you love is struggling with addiction, knowing how to identify the signs of substance abuse is crucial. When it comes to substances like beer, liquor, and psychedelics, dilated pupils can be signs of drug and alcohol disorders requiring a dedicated treatment program. Silver Pines Treatment Center has helped countless patients that have struggled with substance abuse find their road to recovery and receive the support they need to continue moving forward.

If you or a loved one needs personalized addiction treatment services, please don’t hesitate to reach out. Contact our team at 267.209.7313 to learn more about our services and admissions process.

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