Causes
Ingesting a great deal of alcohol in a short amount of time causes alcohol to quickly enter the bloodstream. Mixing alcohol with normal soft drinks, rather than diet drinks delays the dizzying effects of alcohol because the sugary mixture slows the emptying of the stomach, so that drunkenness occurs less rapidly.
The dizzying effects of alcohol upset the fragile mechanism that the inner ear uses to balance.
"Balance in the body is monitored principally by two systems, both of which are affected by alcohol sending abnormal impulses to the brain, that the body is rotating, causing disorientation and making the eyes spin round to compensate."
This "upset" has been seen in experiments in which human subjects were given clinical tests of the vestibular system before and after ingesting alcohol. The alcohol apparently causes the ampullary cupula in the semicircular canal to become lighter than the surrounding fluid (endolymph), which causes the system to become sensitive to gravity in addition to rotational acceleration.
The spins are often reported when alcohol is mixed with cannabis, since both may cause dizziness and magnify each other's effects. Smoking after drinking especially intensifies the effects of the alcohol, often resulting in nausea.
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