Hallucinogen-related disorders are primarily caused by the use of hallucinogenic substances, which include drugs such as LSD, psilocybin (the active compound in magic mushrooms), and mescaline, among others. These substances alter perception, mood, and cognitive processes by interacting with neurotransmitter systems in the brain, particularly serotonin receptors. Genetic predisposition, psychological factors, and environmental influences, such as stressful life events, can also contribute to the onset of these disorders, especially in individuals with a history of mental health issues.