Adherence to (compliance with) drug treatment is important. However, only about half the people who leave a doctor's office with a prescription take the drug as directed. Among the many reasons people give for not adhering to drug treatment, forgetfulness is the most common.
Definition of periodical. 1  1 : periodic 1. 2  2a : published with a fixed interval between the issues or numbersb : published in, characteristic of, or connected with a periodical.
Periodical is a term used to describe any publication that is published multiple times (periodically). Periodicals include materials such as popular magazines, scholarly journals, and newspapers. It is important to understand the difference between a popular and a scholarly periodical. When you are doing research, most of your sources should be scholarly. Often popular periodicals are called magazines and scholarly periodicals are called journals.