If the chemical in question affects the animal mind in some way, then the field of pharmacology is termed “ psychopharmacology.” Psychopharmacology focuses specifically on how drugs affect behavior, moods, and thinking. Psychopharmacologists study everything from how medicines can be used to remedy mental disorders (like depression) to how drugs such as morphine and nicotine cause addiction.

Too much of any drug (an overdose) causes adverse effects, and may even cause the organism to die. Another branch of pharmacology, toxicology, is the examination of why overdoses occur, how much of a drug causes an overdose, and, most importantly, the intervention necessary to prevent death. Toxicologists also try to determine effective antidotes for poisons.

If a drug is supposed to be used as medicine, like the pill you've taken for your headache, scientists in the field of clinical pharmacology decide how that pill could be used effectively. Pharmaceutical researchers discover new drugs; doctors prescribe them. Clinical pharmacologists bridge the two by determining how much of the drug a person should take (its correct dosage) to minimize any harmful side effects without altering the potency (effectiveness) of the drug.

Professionals in research pharmacology and the more familiar pharmacist that you see in a hospital or drug store have gone through years of training in biology, chemistry, biochemistry, and physics in order to become qualified to work in the pharmaceutical field. The result of this training is a PharmD., the “Doctor of Pharmacy.” The steps required to achieve a PharmD. differ between countries. In many countries, a PharmD. is earned after completing a Bachelor's Degree. In the United States, students complete a PharmD. in six consecutive years: two years of pre-pharmacy followed by acceptance into the four year professional degree program.