How does cocaine effect your reaction time?

Cocaine is a stimulant. This means that it increases physiological and nervous activity within the body. At low doses, users experience a temporary enhancement to their hand/eye coordination and reflexes. As the dose is increased, however, there is a marked drop in response time. The abnormally large increase in neuron activity caused by the drug essentially overloads the brain's ability to process information efficiently. This hyper-active state generally results in erratic and erroneous thought processes that are detrimental to performance.

In some users, cocaine can induce a state of hypervigilance - an enhanced state of visio/audio sensitivity with the sole purpose of seeking out threats. The perceived omnipresent danger causes the body to release stress hormones such as cortisol and adrenaline which increase the bodies response times. Heavy users that regularly experience this level of stress will invariably damage their mental health. Anxiety, panic attacks, paranoia and hallucinations are not uncommon.