Final answer:
Irene is likely experiencing the effects of LSD, a hallucinogen known to induce significant sensory and perceptual changes.
Step-by-step explanation:
Irene, age 26, has reported experiencing mystical experiences and heightened awareness, which are symptomatic of hallucinogen use. Among the options provided, LSD (Lysergic acid diethylamide) is most likely to induce such effects. LSD is a potent mood and perception-altering substance capable of causing profound sensory and perceptual changes, including vivid visual hallucinations, distortions in body sensations, and a skewed perception of the passage of time. LSD comes in various forms including 'microdots' and 'window panes', and is characterized by how it can significantly alter a person's reality.