Analysis was performed on the mean of the five assessments conducted 7.5, 8, 8.5, 9, and 9.5 hours post-dose (double-blind) The CTT is a task (duration of 8 minutes) of psychomotor function that entails using a slider to keep a cursor in alignment with a moving target on a visual display unit screen. The movement of the target is the function of an irregular sine wave, and cursor accuracy is measured by the mean tracking error - the difference between the centers of target and cursor in pixels, sampled 5 times per second, over the test. Lower scores are indicative of more accurate tracking.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind) . The CTT is a task (8 minute duration) of psychomotor function that entails using a slider to keep a cursor in alignment with a moving target on a visual display unit screen. The movement of the target is the function of an irregular sine wave, and cursor accuracy is measured by the MTE, the difference between the centers of target and cursor in pixels, sampled 5 times per second, over the test. Lower scores are indicative of more accurate tracking.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind) A further outcome derived from the CTT is a peripheral awareness task where the participant responds to a stimulus presented in the periphery of vision, while simultaneously attending to the tracking test. The mean reaction time, in milliseconds, to these stimuli over the trial period is taken as the response measure for this component of the divided attention task. A lower mean reaction time is indicative of better peripheral awareness.

Critical Flicker Fusion (CFF) is a validated cognitive assessment task that provides an index of central nervous system (CNS) activity and attention modulated motion detection. Participants are required to discriminate flicker from fusion, and vice versa, in a set of four light-emitting diodes arranged in a one-centimetre square. These diodes are held in foveal fixation when viewed at a distance of one metre. Individual thresholds are determined on four ascending and four descending scales. The mean of the four ascending presentations give the ascending threshold frequency in hertz.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind) The mean of the four descending presentations from the CFF give the descending threshold frequency in hertz.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind) The mean of the four ascending and four descending presentations of the CFF give the overall threshold frequency in hertz.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). The Digit Symbol Substitution Test (DSST) is a pen and paper test that consists of rows of blank squares paired with randomly assigned digits (between 0 and 9). Participants are required to substitute each digit with a different nonsense symbol, according to a key printed at the top of the sheet that indicates the nonsense symbol that corresponds to each digit. Participants are given 120 seconds in which to complete the test.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). The Digit Symbol Substitution Test (DSST) is a pen and paper test that consists of rows of blank squares paired with randomly assigned digits (between 0 and 9). Participants are required to substitute each digit with a different nonsense symbol, according to a key printed at the top of the sheet that indicates the nonsense symbol that corresponds to each digit. Participants are given 120 seconds in which to complete the test.

The N-Back task requires the participant to indicate, using the mouse, whether the current stimulus presented on the screen and the one immediately before it visually match (i.e., "one-back"). In the versions of the tests used in this study, the stimuli are presented on screen for 500 ms, and the interval between stimuli is 2500 ms, with a ratio of 1:2 of "match" trials to non-match trials. The duration of the test is 2 minutes. The percentage of correct responses is the percentage of correct responses given in 2 minutes.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). In "3-back" tasks, a comparison is made between the current stimulus and the two before the immediately preceding stimulus. In the versions of the tests used in this study, the stimuli are presented on screen for 500 ms, and the interval between stimuli is 2500 ms, with a ratio of 1:2 of "match" trials to non-match trials. The duration of the test is 2 min. The percentage of correct responses is the percentage of correct responses given in 2 min.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). Reaction time is the time taken to respond to a stimulus.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). Reaction time is the time taken to respond to a stimulus.

The Linear Analogue Rating Scale (LARS) is used as a measure of the subjective effects of psychoactive drugs. Participants mark a series of 10 cm (100 unit line) analogue scales (1-100, 100 = most impaired) relating to dizzy, clumsy, anxious, relaxed, tired, drowsy, alert, energetic, sad, and depressed, indicating their present feeling with regard to a mid-point, representing their "usual" state of mind before treatment began. The higher the score, the more impaired the participant feels. The Tiredness, Alertness, Energy, and Drowsiness scores are averaged to derive an overall Sedation score.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). The Anxiety, Depression, Relaxed, and Sadness scores are averaged to derive an overall "Mood" score (as described in Outcome Measure 14). Each item was assessed on a 1-100 point scale, where 100 indicates most impaired.

Analysis was performed on the individual assessments conducted at 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, and 11.5 hours post-dose (double-blind). The Dizziness and Clumsiness scores are averaged to derive an overall "Coordination" score (as described in Outcome Measure 14). Each item was assessed on a 1-100 point scale, where 100 indicates most impaired.