Methamphetamine and diphenhydramine effects on the rate of cognitive processing

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychopharmacology

Background:

• Cognitive processing speed is a key determinant of performance across various tasks.
• Stimulants like methamphetamine and anticholinergic drugs like diphenhydramine are known to affect cognitive functions, but their specific impacts on processing speed require further elucidation.

Purpose of the Study:

• To investigate the effects of methamphetamine and diphenhydramine on cognitive processing speed.
• To determine if these drugs differentially impact cognitive tasks based on their complexity.

Main Methods:

• A double-blind, placebo-controlled study involving 24 male subjects.
• Administration of oral methamphetamine (10 mg), diphenhydramine hydrochloride (100 mg), and placebo.
• Assessment of cognitive performance on three tasks measuring processing speed, time production, and divided attention before and after drug administration.

Main Results:

• Methamphetamine significantly increased the speed of visual scanning for a target stimulus compared to placebo and diphenhydramine.
• Methamphetamine did not improve performance on time-production or divided-attention tasks.
• Diphenhydramine did not significantly affect performance on any of the cognitive tasks but was associated with altered time perception.

Conclusions:

• Methamphetamine can enhance cognitive processing speed for simple, familiar operations like visual search.
• The benefits of methamphetamine on cognitive speed may not extend to tasks involving complex decision-making or divided attention.
• Diphenhydramine appears to influence time perception more than rapid cognitive processing performance.