Final answer:
b) Suppression
Consistent barbiturate use leads to suppression of the reticular formation, a part of the brain that contributes to wakefulness and can cause drowsiness or sedation.
Step-by-step explanation:
The effect of consistent barbiturate drug use on the reticular formation is suppression. Barbiturates are central nervous system depressants that interact with the GABA neurotransmitter system, increasing the inhibitory effect of GABA and leading to a sedative effect. This interaction generally causes a decrease in the activity of the neural circuits within the reticular formation, which is involved in regulating wakefulness and sleep-wake transitions among other functions.
Because the reticular formation plays a crucial role in maintaining consciousness and alertness, its suppression by barbiturates can lead to drowsiness, sedation, or even coma with an overdose. In contrast, substances that are central nervous stimulants, such as cocaine and amphetamine, would lead to hyperactivity in the reticular formation.