Over the weekend I saw the movie Limitless.


In that, the main character takes a drug, and he says that because of his prolonged usage of the drug, his synapses changed permanently.

This is not the first time I have heard such a claim. For example, that a heroin users' brain chemistry and balance changes after its first use.

So I was wondering:

  • Can the prolonged usage of drugs permanently change your neurology and thus your personality?

  • Do people who take anti-depressants for a while, and then stop, become less depressed individuals?

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    Absolutely. We find that patients on long-term daily opioid have very significantly reduced pain thresholds.
    – user2466
    Commented Jun 26, 2011 at 13:03
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    Surely the passage of time itself can be correlated with synapse change, irrespective of drug use. All is flux.
    – James
    Commented Jun 26, 2011 at 20:35
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    @James: True. But we can follow 2 groups over time. Group A was 'exposed' to the drug; group B, the control, is 'unexposed'. Now we can see what difference the drug use itself had on the people in the groups.
    – user2466
    Commented Jun 27, 2011 at 4:24
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    I wonder if you would get better responses if you split your two questions in separate posts. For your second question, you need to provide evidence that it is a notable claim for it to be on topic. Has anyone actually made this claim, or are you just wondering? (Or was anti-depressants the type of drug used in Limitless?)
    – Oddthinking
    Commented Jun 30, 2011 at 5:29
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    @Itai, oh so you are just looking for a general answer about all drugs; they don't need to address anti-depressants (like Randolf's)? Then I would remove the anti-depressant line. It is confusing.
    – Oddthinking
    Commented Jun 30, 2011 at 10:20

1 Answer 1


This document, Chronic Amphetamine Use and Abuse, goes into great detail on the effects of chronic amphetamine use and abuse, and will hopefully help to answer your question:


Neurotoxic Effects of Stimulant Drugs

"Sustained high-dose administration of amphetamines (especially methamphetamine) to experimental animals produces a persistent depletion of [dopamine] which is associated with terminal degeneration (62, 182, 195), as well as neuronal chromatolysis in the brain stem, cortex and striatum (42, 182). ..."

I expect that different drugs will have different effects, both long-term and short-term, and since you didn't specify a particular drug I thought amphetamines would be a good one to look at because crystal meth in particular is known to be one of the dangerous ones (particularly with illegal meth labs, that police keep having to shut down, and then reports on the radio follow with observations that there may have been attempts to save money or create something unique by substituting or mixing in other chemicals which, if true, could result in the creation of an even more dangerous substance).

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    Any information on long-term Opiate use?
    – Nobody
    Commented Jun 30, 2011 at 10:45
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    @rmx: I couldn't find anything with a quick search, although from official Canadian Government sources (including legislative) there seems to be a strong concern about long-term treatment strategies (that should be a "red flag" to anyone who's considering using Opiates) -- this Google Search which will focus on this type of information (hopefully it will be helpful to you): google.com/search?q=long-term+opiate+use+site:gc.ca Commented Jun 30, 2011 at 18:55
  • For the interaction of opioid tolerance and pain sensitivity, the work of LR Watkins is the place to look. See Watkins LR, Hutchinson MR, Johnston IN, Maier SF (2005) Glia: novel counter-regulators of opioid analgesia. Trends in Neurosciences 28:661-669. for a good review. In layperson's terms: the body has inbuilt systems to adjust its pain sensitivity. When you consistently mute the system with opiates, it responds by "turning the volume up". Not only do the opiates lose effectiveness, but the baseline levels of pain increase as well.
    – Craig
    Commented Nov 1, 2011 at 12:57
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    @Craig opiates don't just alter your pain treshold, they also alter your personality. Many people taking them long term tend to get more aggressive, short tempered, argumentative (I've seen this close up sadly).
    – jwenting
    Commented Sep 17, 2013 at 5:18

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