Psychoactive drugs exert their effects on the behavior, actions, and mental health states of a person by altering neuronal communication in the brain. This is done through neurotransmitters and the majority of drugs reach the brain by traveling in the blood. The time taken to reach the brain depends on the type of drug, the dosage, and the personal tolerance levels of the person. The tolerance levels of the person is influenced by the frequency of consumption and other bodily traits.