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.
Psychoactive substances often bring about subjective (although these may be objectively observed) changes in consciousness and mood that the user may find rewarding and pleasant (e.g. euphoria) or advantageous (e.g. increased alertness) and are thus reinforcing.here are many ways in which psychoactive drugs can affect the brain. Each drug has a specific action on one or more neurotransmitter or neuroreceptor in the brain. Drugs that increase activity in particular neurotransmitter systems are called agonists.