With a little help from my ‘friends’: The mood- and cognition-enhancing effects of illicit substances

High levels of competition, workload, and pressure regarding study and work-related performance are very common in students' and young professionals' lives. To achieve and maintain high cognitive performance and counteract possible negative mood changes due to stress or pressure, the use of pharmacological interventions, such as illicit substances, to enhance cognitive performance and mood is not uncommon. These substances include cocaine, cannabidiol (CBD), a constituent of cannabis, and psychedelic substances like Lysergic Acid Diethylamide (LSD), in small doses (‘microdosing’). While most of the perceived effects of cocaine, CBD, and microdoses of LSD on mood and cognition seem positive, the evidence is mixed or based on user claims. Furthermore, additional factors such as an individual's trait and state at the time of substance use might influence the effects of cocaine, CBD and LSD on cognition and mood. This thesis objectively examined the proclaimed cognition and mood enhancing effects of cocaine, LSD, and CBD in placebo-controlled experimental studies, and assessed whether drug-induced enhancement on cognition and mood depended on personality traits such as empathy and anxiety, drug-induced states of arousal and positive mood, and baseline state of anxiety.