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Could you elaborate on that? If the idea is that dopamine causes schizophrenia (to oversimplify things), I don't see why increasing dopamine with a cigarette wo

by lars 15y ago

Could you elaborate on that? If the idea is that dopamine causes schizophrenia (to oversimplify things), I don't see why increasing dopamine with a cigarette would work as self-medication for a schizophrenic.

jarin 15y ago
"A brain chemical called dopamine may help encode what counts as relevant information in the human brain, researchers say." I think the theory is that a lack of dopamine is what causes schizophrenia, by making it harder for the brain to determine what information is relevant or not.
- lars 15y ago
  Aha. But I think it's the other way around, schizophrenia is treated by dopamine suppressors, so too much dopamine means the brain takes all information to be relevant.
- logjam 15y ago
  Schizophrenia is a complex disease, but most hypotheses have centered on hyperactive rather than hypoactive dopaminergic activity: http://en.wikipedia.org/wiki/Dopamine_hypothesis_of_schizophrenia http://en.wikipedia.org/wiki/Dopamine_hypothesis_of_schizoph... There is indeed greater nicotine use by those diagnosed with schizophrenia, but the reasons are likely complex. Self-treatment of some symptoms may be involved, but they may be more associated with nicotine's anxiolytic activity or relief of some of schizophrenia's negative symptoms (e.g., apathy), rather than positive symptoms like frank psychosis.
  - jarin 15y ago
    Ah, ok I misunderstood what I read.
- scythe 15y ago
  A lack of dopamine (especially in the extrapyramidal system) is what causes Parkinson's. An excess of dopamine (especially in the mesolimbic pathway) is what causes schizophrenia. Nicotine does increase dopamine in the brain, but only in the same way that my car plays music. It does that, but it's not really relevant to the way nicotine works -- nicotine acts to stimulate an ion channel called the nicotinic acetylcholine receptor. This ion channel stimulation causes several downstream effects, most notably the release of endorphins (biomolecules which mimic the function of morphine), and also the release of adrenaline (which increases focus and concentration).

by lars 15y ago

jarin 15y ago

"A brain chemical called dopamine may help encode what counts as relevant information in the human brain, researchers say." I think the theory is that a lack of dopamine is what causes schizophrenia, by making it harder for the brain to determine what information is relevant or not.

lars 15y ago
Aha. But I think it's the other way around, schizophrenia is treated by dopamine suppressors, so too much dopamine means the brain takes all information to be relevant.
logjam 15y ago
Schizophrenia is a complex disease, but most hypotheses have centered on hyperactive rather than hypoactive dopaminergic activity: http://en.wikipedia.org/wiki/Dopamine_hypothesis_of_schizophrenia http://en.wikipedia.org/wiki/Dopamine_hypothesis_of_schizoph... There is indeed greater nicotine use by those diagnosed with schizophrenia, but the reasons are likely complex. Self-treatment of some symptoms may be involved, but they may be more associated with nicotine's anxiolytic activity or relief of some of schizophrenia's negative symptoms (e.g., apathy), rather than positive symptoms like frank psychosis.
- jarin 15y ago
  Ah, ok I misunderstood what I read.
scythe 15y ago
A lack of dopamine (especially in the extrapyramidal system) is what causes Parkinson's. An excess of dopamine (especially in the mesolimbic pathway) is what causes schizophrenia. Nicotine does increase dopamine in the brain, but only in the same way that my car plays music. It does that, but it's not really relevant to the way nicotine works -- nicotine acts to stimulate an ion channel called the nicotinic acetylcholine receptor. This ion channel stimulation causes several downstream effects, most notably the release of endorphins (biomolecules which mimic the function of morphine), and also the release of adrenaline (which increases focus and concentration).