Final answer:
Alcohol is the drug that high school seniors most commonly use, and it is recognized as a depressant with serious potential side effects including poor coordination, slurred speech, and at very high doses, life-threatening consequences.
Step-by-step explanation:
Among high school seniors, the most widely used drug is alcohol. According to various studies and reports, the recreational use of psychoactive substances such as alcohol is common. Alcohol is considered a depressant, and its use can lead to various symptoms depending on the dose. Low doses can result in mild sedation and poor coordination, while higher doses can lead to more severe impairments like slurred speech, trouble walking, and vomiting. In extreme cases, consuming alcohol can lead to respiratory depression, coma, or even death. It is important to recognize that despite being a legal substance, alcohol can pose significant risks, particularly to teenagers and young adults.
Marijuana is another commonly used psychoactive drug, although its legal status varies across jurisdictions. Less common drugs used by high school seniors might include stimulants, opioids, and classic hallucinogens like LSD. While illegal substance use such as LSD is generally lower among high school seniors than the use of alcohol, awareness and education on the risks associated with all types of drug use are essential.