Driving requires concentration, motor skills and concern for the safety of everyone on the road. Psychoactive substance use or misuse has the potential of making driving unsafe. It puts both the driver, passengers and other road users at a great risk. Under the influence of substances, drivers are prone to motor vehicle collision and accidents. This could be worsened if they are suffering from mental conditions that can affect their mood, judgement, cognition and behaviour.
Depressive symptoms have been linked to driving alter drinking, and psychological distress has been associated with risky driving behaviours (Stoduto et al, 2008) and (Scott-Parker et al., 2012). Mania can reduce alertness, worsen judgement or make drivers easily distractible and could lead to impaired driving. Different substances have different effects on the brain of theuser depending on their mechanism of action, amount consumed and the health history of the user among other factors. Marijuana slows reaction time, impairs judgement and decrease motor coordination and alcohol impairs judgement also. As a result, the drivers who used them will be unable to judge time and distance properly.
Sedatives such as benzodiazepines cause dizziness and drowsiness which put drivers at risk of accidents. Cocaine and similar drugs can produce aggression and reckless driving in users. Combination of drugs such as alcohol and marijuana is responsible for most lane weaving while driving (Hartman et al., 2013).
