Which of the following are considered central nervous stimulants?

Central nervous stimulants are substances that increase neural activity in the brain, leading to enhanced alertness, attention, and energy levels. Amphetamines are a prime example of central nervous stimulants. They work primarily by increasing the levels of certain neurotransmitters, such as dopamine and norepinephrine, in the brain, resulting in heightened wakefulness and increased focus.

In contrast, opiates, barbiturates, and alcohol have depressant effects on the central nervous system. Opiates are primarily used for pain relief but can cause drowsiness and sedation. Barbiturates are sedatives that can also lead to decreased brain activity, and alcohol is a well-known depressant that impairs cognitive functions and motor coordination.

This understanding of the effects and classifications of these substances is crucial for crime scene analysts, as recognizing the type of drug involved in a situation can significantly impact the interpretation of evidence and the investigation's direction.