This study investigated the psychotomimetic effects of intravenous delta-9-tetrahydrocannabinol (Δ-9-THC) in 22 healthy individuals who had been exposed to cannabis but were not diagnosed with a cannabis abuse disorder. The study used a double-blind, randomized, and counterbalanced design to assess the behavioral, cognitive, and endocrine effects of 0, 2.5, and 5 mg doses of Δ-9-THC. Key findings include: 1. **Behavioral Effects**: Δ-9-THC produced schizophrenia-like positive and negative symptoms, altered perception, increased anxiety, produced euphoria, disrupted immediate and delayed word recall, impaired performance on tests of distractibility, verbal fluency, and working memory, and increased plasma cortisol levels. 2. **Cognitive Measures**: Δ-9-THC significantly impaired immediate recall and delayed free recall, impaired performance on a computerized visual working memory task, and reduced correct responses in the easy subtask of a computerized working memory task. 3. **Endocrine Effects**: Δ-9-THC increased plasma cortisol levels but did not significantly affect serum prolactin levels. 4. **Safety Data**: No serious adverse events occurred during the study. Follow-up assessments at 1, 3, and 6 months post-study showed no new psychiatric symptoms or changes in cannabis use. The study suggests that Δ-9-THC can produce a range of transient symptoms, behaviors, and cognitive deficits in healthy individuals that resemble aspects of endogenous psychoses. These findings have implications for understanding the potential role of brain cannabinoid receptor function in the pathophysiology of psychotic disorders.This study investigated the psychotomimetic effects of intravenous delta-9-tetrahydrocannabinol (Δ-9-THC) in 22 healthy individuals who had been exposed to cannabis but were not diagnosed with a cannabis abuse disorder. The study used a double-blind, randomized, and counterbalanced design to assess the behavioral, cognitive, and endocrine effects of 0, 2.5, and 5 mg doses of Δ-9-THC. Key findings include: 1. **Behavioral Effects**: Δ-9-THC produced schizophrenia-like positive and negative symptoms, altered perception, increased anxiety, produced euphoria, disrupted immediate and delayed word recall, impaired performance on tests of distractibility, verbal fluency, and working memory, and increased plasma cortisol levels. 2. **Cognitive Measures**: Δ-9-THC significantly impaired immediate recall and delayed free recall, impaired performance on a computerized visual working memory task, and reduced correct responses in the easy subtask of a computerized working memory task. 3. **Endocrine Effects**: Δ-9-THC increased plasma cortisol levels but did not significantly affect serum prolactin levels. 4. **Safety Data**: No serious adverse events occurred during the study. Follow-up assessments at 1, 3, and 6 months post-study showed no new psychiatric symptoms or changes in cannabis use. The study suggests that Δ-9-THC can produce a range of transient symptoms, behaviors, and cognitive deficits in healthy individuals that resemble aspects of endogenous psychoses. These findings have implications for understanding the potential role of brain cannabinoid receptor function in the pathophysiology of psychotic disorders.