Hallucinogens: Clinical Considerations, Neurobiology, and Treatment Considerations is a self-paced professional training designed for clinicians who want to better understand how hallucinogenic and dissociative substances affect perception, cognition, emotional processing, client presentation, diagnosis, and treatment planning. Hallucinogens represent a complex and clinically important category of psychoactive substances because their effects are often highly variable, context-dependent, and influenced by the individual’s psychological state, environment, trauma history, and patterns of use. This course provides a practical, clinically relevant overview of major hallucinogen categories, including serotonergic psychedelics such as LSD and psilocybin, dissociative substances such as ketamine, PCP, and dextromethorphan, and related substances with overlapping stimulant, empathogenic, or perceptual effects. Participants will explore the neurobiological mechanisms associated with hallucinogen use, including effects on serotonin, glutamate, dopamine, norepinephrine, cortical signaling, sensory integration, the default mode network, altered consciousness, and emotional salience. The training also addresses acute, subacute, and long-term clinical effects, including perceptual distortion, panic reactions, dissociation, impaired judgment, substance-induced psychosis, flashbacks, Hallucinogen Persisting Perception Disorder, anxiety, mood disturbance, and functional impairment. Clinical implications for assessment, differential diagnosis, and treatment are emphasized throughout the course, particularly in the context of hallucinogen-related presentations, co-occurring mental health conditions, trauma, polysubstance use, psychological vulnerability, and emerging cultural perceptions of psychedelic and dissociative substance use. Participants will also consider applied case examples to strengthen clinical decision-making, psychoeducation, risk assessment, treatment planning, r