- Delta9-tetrahydrocannabinol (THC) is the main psychoactive constituent of Cannabis sativa L (Marijuana) plant.
- Other marijuana-derived cannabinoids includes Cannabichromene (CBC), Cannabidiol (CBD), Cannabinol (CBN), Cannabigerol (CBG), Tetrahydrocannabivarin (THCV).
- Marijuana-derived cannabinoids are known as phytocannabinoids.
Antidepressant properties of THC
- THC stimulate anandamide biosynthesis by binding to the CB1 receptor, thus producing a antidepressant and neuroprotective effect. 
Neuroprotective properties of THC
- THC inhibit acetylcholinesterase (AChE)-induced intraneuronal amyloid beta aggregation in Alzheimer's disease: 
- THC prevent intracellular amyloid beta proteotoxicity and inflammatory response: 
- THC is effective as antiglutamatergic therapy for NMDA-induced excitotoxicity. 
- Unlike THC, caffeine is a noncompetitive reversible inhibitor of AChE.
- THC reduce intraocular pressure (IOP) in retinal ganglion cells (RGCs) through intracellular CB1 receptor activation; A potential treatment for glaucoma to prevent optic nerve damage.
Proneurogenic effects of THC on neurogenesis and BDNF signaling
- Hippocampal CB1 receptors regulate stress-induced neuroinflammation in the hippocampus. 
- THC enhance adult hippocampal neurogenesis and BDNF signaling through intracellular CB1 receptor activation. 
- Intracellular CB1 activation promote neuronal cell proliferation, differentiation, maturation, and neurite growth. 
Neuropsychology of THC tolerance
- CB1 receptor sensitization can be restored by taking breaks of oral THC administration. (Reference needed)
- Alcohol increase THC levels in blood. (Reference needed)
- THC tolerance is genetic and regulated by the AKT1 gene.
- Synaptogenic effect of THC/DHA promote hippocampal development (neurogenesis) and synaptogenesis.
- THC/DHA affect neural stem/progenitor cells (NS/PC) proliferation in the hippocampus.
- THC enhance corticostriatal functional connectivity though increased c-Fos expression.
Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L
A molecular link between the active component of marijuana and Alzheimer's disease pathology.
Amyloid proteotoxicity initiates an inflammatory response blocked by cannabinoids
Endocannabinoid signaling in neurotoxicity and neuroprotection.
Regulatory role of cannabinoid receptor 1 in stress-induced excitotoxicity and neuroinflammation.
Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects.
Alzheimer's disease; taking the edge off with cannabinoids?
Activation of type 1 cannabinoid receptor (CB1R) promotes neurogenesis in murine subventricular zone cell cultures.