The effects of CBD and THC in animal models of depression and anxiety

• Published in: Clinical neurophysiology Vol. 130; no. 8; pp. e118 - e119
• Main Authors: Liu, Junhan, Burnham, McIntyre
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2019
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2019.03.023

Epilepsy patients frequently suffer from psychiatric comorbidities, such as depression and anxiety, which seriously affect their quality of life. CBD has been reported to have not only anti-seizure effects, but also to have possible anxiolytic and antidepressant effects. Thus, CBD might treat not only seizures but also the comorbidities associated with seizures. The present study was designed to test the effects of THC, CBD and a combination of CBD and THC (15:1 ratio) in mice models of anxiety (the elevated plus maze EPM) and depression (the forced swim test FST). EPM Adult, male CD1 mice (30–35 g) were injected i.p. with CBD (0, 3, 6, 12, 24, 48, 96 mg/kg), THC (0, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4 mg/kg), CBD + THC (0, 3 + 0.2, 6 + 0.4, 12 + 0.8, 24 + 1.6, 48 + 3.2, 96 + 6.4 mg/kg) or diazepam (positive control, 0, 2.5 mg/kg). They were then tested in the EPM for 5 min. FST Adult, male CD1 mice (30–35 g) were injected i.p. with CBD (0, 7.5, 15, 30, 60, 120 mg/kg), THC (0, 0.5, 1, 2, 4, 8 mg/kg), CBD + THC (0, 7.5 + 0.5, 15 + 1, 30 + 2, 60 + 4, 120 + 8 mg/kg) or imipramine (positive control, 0, 30 mg/kg). They were tested in the FST (6 mins) or in open field arena (60mins). CBD was injected 60mins prior to testing and THC was tested 30mins prior to testing. Mice were tested only once. N = 10–15 for each dose. CBD did not have significant effects in either test at any dose. THC caused a significant increase in the time spent in the open arms of the EPM at 3.2 and 6.4 mg/kg, and significantly decreased immobility time in the FST at 2 mg/kg without affecting open field activity. The combination of CBD and THC was no different than THC alone. CBD did not show anxiolytic or antidepressant effects in our animal models. THC, however, had both anxiolytic and antidepressant effects at some doses. Conceivably, a combination of CBD and THC might be useful in patients with combined seizures and psychiatric comorbidities. The cannabinoids used in this work were donated by MedReleaf (Markham, ON). This study was supported in part by EpLink – The Epilepsy Research Program of the Ontario Brain Institute.