The monoterpenes ⍺-pinene and limonene augment or mitigate THC-induced impairments in sustained attention in rats.

Moore C.; Wilberger T.; Jenkins B.; Vandrey R.; Weerts E. · Psychopharmacology · 2026

**Background & Methods** This preclinical study investigated whether two cannabis-derived monoterpenes (α-pinene and limonene) could modulate THC-induced cognitive impairment in 24 male and female Sprague-Dawley rats trained on the rodent psychomotor vigilance task (rPVT). Rats received oral gavage administration of THC, terpenes, or vehicle 60 minutes prior to sustained attention testing, with outcomes analyzed using linear mixed models. **Key Findings** - THC demonstrated dose-dependent cognitive impairment, reducing accuracy and increasing attention lapses on the rPVT at doses of 3 and 10 mg/kg. - α-pinene (100 mg/kg) alone impaired performance but showed dose-dependent bidirectional effects when combined with THC: exacerbating impairments at moderate THC dose (3 mg/kg) while partially mitigating deficits at high THC dose (10 mg/kg) at lower terpene doses (10-30 mg/kg). - Limonene (10-100 mg/kg) alone produced no cognitive effects but demonstrated selective mitigation of THC-induced impairments at the moderate THC dose (3 mg/kg), with no protective effects at the higher THC dose (10 mg/kg). **Dosage & Administration** THC doses: 3 and 10 mg/kg orally. Terpene doses: 10-100 mg/kg (α-pinene and limonene) orally via gavage. Vehicle control: sesame oil. Administration timing: 60 minutes prior to testing. **Safety & Adverse Effects** Not reported. The study focused on cognitive performance outcomes without systematic assessment of behavioral or physiological adverse effects. **Evidence Quality** This is a preclinical rodent study with significant limitations for human applicability. The small sample size (n=24), controlled laboratory conditions, and single-dose acute administration do not reflect real-world cannabis use patterns. The study lacks mechanistic investigation of terpene-cannabinoid interactions at the molecular level. Results are promising for the concept of cannabinoid-terpene modulation but require human clinical validation before informing patient recommendations. The dose-dependent and bidirectional effects observed suggest complex pharmacological interactions requiring further investigation. Publication in 2026 reflects emerging research in this area with limited prior empirical evidence supporting common claims about terpene effects on THC.

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