Acidic cannabinoids in brain disorders: Neurobiological mechanisms, preclinical evidence, and translational challenges.

Acidic cannabinoids, including tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), and related biosynthetic precursors, represent the predominant phytocannabinoid forms naturally produced by Cannabis sativa. Long considered pharmacologically inactive intermediates, these compounds are now increasingly recognized as bioactive molecules with potential therapeutic relevance for brain disorders. Compared with their decarboxylated counterparts, acidic cannabinoids exhibit distinct physicochemical, pharmacokinetic, and pharmacodynamic properties that may confer reduced psychotropic liability together with unique neurobiological effects. Emerging preclinical evidence indicates that acidic cannabinoids modulate multiple processes implicated in neurological and psychiatric disorders, including serotonergic and endocannabinoid signaling, neuroinflammation, oxidative stress, mitochondrial dysfunction, calcium dyshomeostasis, and synaptic transmission. In this review, we critically examine current knowledge regarding acidic cannabinoids in the context of brain disorders. We first summarize their biosynthesis, chemical stability, pharmacokinetic characteristics, and pharmacological differences from neutral cannabinoids. We then examine preclinical evidence supporting their potential therapeutic effects in epilepsy, anxiety, depression, psychosis-related conditions, and neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. We also discuss how artificial intelligence and computational approaches may support target identification, formulation optimization, pharmacokinetic modeling, and the development of personalized cannabinoid-based interventions. Finally, we highlight key methodological and translational challenges limiting the field and outline priorities for future research. Overall, acidic cannabinoids emerge as promising but still underexplored multitarget compounds with potential relevance for the treatment of brain disorders.