No, an employer may accept a negative/dilute test result as a negative test. If the employer wants a retest it may do so, however, it must be stated in the employer's policy and the employer must require a retest of all individuals that have a negative/dilute result in the same testing category.
Alcohol affects activity of such neurotransmitters as glutamate, GABA, and dopamine; caffeine blocks the action of the neurotransmitter adenosine. Such changes are studied in the field of psychopharamacology, which concerns the effects of drugs on the mind and brain. This field investigates both recreational drugs such as alcohol, caffeine, marijuana, cocaine, and LSD, and therapeutic drugs such as antidepressants and antipsychotics.
Dr. Charles Sophy, discusses the effects drugs and alcohol have on the human brain. Dr. Sophy describes how the brain is affected by changes in the balance of chemicals. This in turn makes changes to mood, anxiety levels and behaviors. He explains how the brain of an addict and non-addict differs.