After hanging around enough of my moronic MDMA-using mates, I’ve got a question to ask - why do pupils expand when affected by drugs? It happens on marijuana, alcohol and a whole lot of other illicit substances. So, does anyone have an answer?
I’ve never noticed it with Alcohol or Marijuana.
Marijuana increases blood flow to the eyes and the blood vessels become engorged in occasional users. Hence the blood-shot look of recent marijuana smokers. Marijuana also makes it impossible for you to cross your eyes.
With MDMA and LSD and similar psychoactives your pupils dilate to a great degree, sometimes to the point where the iris is invisible.
Other drugs cause the pupils to become unreactive, meaning exposure to brighter light won’t cause them to dilate.
There is a medical term for drug induced pupil dilation, but unfortunately I’ve forgetten it and can’t find it. Nor can I give you the biological reasons these drugs act the way they do on the eyes.
Are you sure? I used to smoke marijuana and hashish, and don’t remember ever having problems crossing my eyes. I can cross my eyes, hold one crossed, and rotate the other, and did it for a joke… I would think that my friends would have told me if it were not working! (I can even do wall-eyed…)
I can’t help with the term but I’m pretty sure the effects are borne out due changes in the sympathetic nervous system (or more accurately, sympathetic division of the ANS).
because many drugs of abuse are sympathomimetics (blocking the uptake of norepinephrine) or anticholinergics (blocking the activity of acetylcholine), which results in eye dilation (mydriasis).
Sympatholytics cause miosis, or pupic constriction. These are far less common drugs of abuse and include alpha and beta-blockers.
And that nonsense about not being able to cross your eyes while on marijuana is a common stoner myth.
QtM, MD
I think we have a winner.
With first hand experience, the Police use it as a “marijuana” sobriety test. Finger is placed just in front of your nose and you’re told to focus on it. You can’t fully converge or hold convergence. I’ve tried.
Now if you can provide me with a medical cite I’ll gladly admit I was imagining it all.
Damn, I would be hosed.
I can’t cross my eyes any time.
That’s not how it works, Eidolon. This is, after all, GQ. You make the assertion that marijuana keeps one from crossing their eyes, you need to provide a reputable medical cite.
Here’s a nice paper for you: It shows how marijuana affects involuntary (autonomic) nerve functioning of the oculomotor system, but leaves the voluntary functions under control:
Marijuana slows smooth pursuit eye tracking and reduces light reflex; Pickworth.; Addiction Research Center, National Institutes of Health (1997)
Also this:
from http://www.roads.dft.gov.uk/roadsafety/cannabis/5.htm This article draws on more of Dr. Pickworth’s research.
Basically cannabis affects the non-voluntary eye motion component, but not the voluntary.
So in short, you said it, you prove it.
As Qadcop points out, some chemicals dilate and some constrict the pupils. As far as the police using not being inability to hold convergence to real close objects I think it is meaningless. Some police use a lot of rough and ready methods that don’t have a lot of scientific backing. Can our lawyers comment on whether or not such a “failure to converge,” without any other signs, is sufficient cause for a drug arrest?
It’s not at all uncommon to see prisoners who have taken drugs where the ride has long finished but some effects take longer to leave the system.
Where I work it is well known among cons that drug testing does not take place at weekends, and some drugs can be taken on Friday and be clear enough to provide negative samples on the Monday when testing resumes.
One affect effect is that pupils can become very small, which is known in jail parlance as being “pinned”, as in pinholes I guess.
It might be a counter reaction to certain drugs that cause the pupil to widen, and when that drug has left the body, it is still overcorrecting.
Or it could be the direct reaction to some other drugs. Drugs in the opiate family cause the pupils to get very small…in fact, you’ll hears users often warn one another that there pupils are “pinned”.
From what you say, I assume you work in a prison. I can understand one who has a chance of release not wanting to screw it up by failing a drug test, but why would the lifers give a shit? Solitary? Torture?
Road Rash
There are often threads that ask questions about prisons and prison issues, so much so, that it gets tedious introducing every post I make, with…
I work in a Cat C prison in the UK as an instruction/workshops officer…
In the UK we do not have many natural life term prisoners, around 23 or so, and there are some others who will die in persons from age related conditions.
This means that at least 99% of UK prisoners will be released at some point, and in the case of serious crimes such as murder etc where the sentence is a tariff of a number of years plus a lifelong monitoring under licence conditions, then something like a positive test can screw up parole, or progression to an easier jail, at any rate it can cost such a prisoner years of time depending on when the date for the next parole hearing is set.
On the crossing the eyes bit, the claim that you can not cross them is BS. I am, in fact, doing it right now.