In People v. Vanzandt, 287 Ill. App. 3d 836, 845, 223 Ill. Dec. 186, 679 N.E.2d 130 (1997), the defendant was acquitted of DUI but was found guilty of driving under the combined influence of alcohol and drugs. At trial, the defendant presented evidence that he was diabetic and that he had taken insulin several hours previously during the evening before his arrest. He contended that his behavioral symptoms were the result of a hypoglycemic attack. The defendant in Vanzandt never admitted to "being under the influence" of insulin. The reviewing court concluded that there was no evidence offered that would indicate that insulin, either by itself or in combination with alcohol, would render a person incapable of driving safely. Although the officer testified that alcohol would affect a diabetic's blood sugar level and this in turn would affect a person's coordination and ability to think clearly, the reviewing court concluded that the officer was not qualified to give expert testimony on the complex physiological effects that alcohol produces in diabetics. Because the State otherwise failed to produce any evidence that the defendant was under the combined influence of alcohol and insulin, the reviewing court reversed the conviction.