The effects of methamphetamine on driving performance and behavior: A thematic linking of consumption patterns and cognitive-behavioral outcomes from in-depth interviews with methamphetamine users.

Objective: This study sought to investigate the thematic links between methamphetamine (MA) users' consumption patterns; their perceptions about the effects that MA has on their thoughts, feelings, and behavior; and their tendency to drive following MA consumption.

Methods: Seventeen MA users were recruited through a combination of social media advertising and third-party outreach. Participants completed a semi-structured interview lasting approximately 30 min. Interview data were analyzed using thematic analysis to identify key patterns undermining impaired driving behavior.

Results: An overarching theme revealed that participants' beliefs about MA use and their tendency to drive while intoxicated were largely dependent on their history and patterns of MA use. Three primary profiles of MA users were identified: (a) sporadic users, who used "speed" infrequently and in the context of social situations; (b) progressed users, who described similar initial patterns but had progressed to frequent use of more potent "crystal" MA and displayed characteristics of substance dependency; and (c) regressed users, who acknowledged a previous history of problematic use, but had since reduced their use patterns significantly. Where sporadic users tended to perceive MA as detrimental to their attention and behavior on the road, progressed users commonly believed that MA positively influenced their driving. However, it was typically acknowledged among all users that regardless of intoxication, extended MA use could lead to significant driving risk due to the severe cognitive (erratic thinking) and behavioral (aggression) symptoms associated with fatigue and the 'come down' of MA. Finally, the analysis showed that the tendency to drive while intoxicated was contextual to participants' beliefs about the associated cognitive-behavioral outcomes of MA use.

Conclusions: The findings highlight how MA use patterns and perceptions contribute to impaired driving behaviors. These insights can inform the development of more targeted interventions addressing the interconnected issues of substance dependence and drug-impaired driving.