Final answer:
Stimulants increase brain activity and beta waves, causing alertness, while depressants slow brain activity, encouraging calming effects with slower waves. The consumption of these substances alters brainwave patterns, which affect consciousness and can potentially lead to addiction.
Step-by-step explanation:
The changes in brainwave activity when stimulants and depressants are taken vary significantly, as these substances have opposite effects on the central nervous system. Stimulants like caffeine, nicotine, and amphetamines such as Adderall increase brain activity, resulting in higher frequencies of beta waves, which are associated with alertness and wakefulness. On the other hand, depressants including ethanol and opioids like codeine and heroin lead to a decrease in brain activity, resulting in slower brainwave frequencies like alpha waves during wakefulness and theta and delta waves during stages of sleep, reflecting a calming effect and reduced anxiety.
Anxiolytics, such as benzodiazepines, and some antidepressants decrease abnormal excitement in the brain, effectively reducing anxiety and leading to brainwave patterns similar to those found in natural sleep states. Hence, the use of these substances can alter our consciousness, mood, perceptions, thinking, and behavior, which sometimes results in addiction.