Background. Depression is the most common psychiatric comorbidity in people living with epilepsy, affecting approximately 25–35% of patients. Antidepressants are typically prescribed for depression, but they only provide relief in about two-thirds of patients. Recent research suggests that the cannabinoids might provide a new therapy for depression in both epileptic and non-epileptic patients.

Methods. The effects of cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), and combinations of CBD and THC were tested in a mouse model of depression (the forced swim test, FST) and locomotor activity (the open field test, OFT). Adult, male CD-1 mice were injected intraperitoneally with CBD (0 or 30 mg/kg), THC (0 or 2 mg/kg) or CBD + THC (0 + 0, 30 + 1, 30 + 2 mg/kg). They were then tested for 30 min in the OFT and for 6 min in the FST.

Results. As compared to vehicle, CBD, and THC both significantly decreased the time spent immobile and increased the time spent swimming in the FST. THC, however, also significantly increased locomotor activity in the OFT, suggesting a non-specific effect. In combination, CBD and THC lost their effects in both tests and did not differ from vehicle.

Conclusions. These results suggest that CBD might be potentially useful for people living with depression. In the present study, however, combinations of CBD and THC had an infra-additive effect rather than the supra-additive effect reported in a previous study. Since CBD and THC in combination produced effects that are less than the sum of the drugs alone (1 + 1 > 2), this may suggest the presence of antagonistic interactions between these two cannabinoids.

This research was conducted with the support of EpLink - the Epilepsy Research Program of the Ontario Brain Institute.

背景。抑郁症是癫痫患者最常见的精神共病，影响了大约 25-35% 的患者。抗抑郁药通常用于治疗抑郁症，但它们只能缓解约三分之二的患者。最近的研究表明，大麻素可能为癫痫和非癫痫患者的抑郁症提供一种新的治疗方法。

方法。大麻二酚 (CBD)、Δ9-四氢大麻酚 (THC) 以及 CBD 和 THC 组合的影响在抑郁症（强迫游泳试验，FST）和运动活动（旷场试验，OFT）的小鼠模型中进行了测试。成年雄性 CD-1 小鼠腹膜内注射 CBD（0 或 30 mg/kg）、THC（0 或 2 mg/kg）或 CBD + THC（0 + 0、30 + 1、30 + 2 mg/kg） . 然后他们在 OFT 中测试了 30 分钟，在 FST 中测试了 6 分钟。

结果。与车辆相比，CBD 和 THC 都显着减少了静止不动的时间并增加了在 FST 中游泳的时间。然而，THC 也显着增加了 OFT 的运动活性，表明存在非特异性作用。结合起来，CBD 和 THC 在两个测试中都失去了效果，并且与车辆没有区别。

结论。这些结果表明 CBD 可能对患有抑郁症的人有用。然而，在本研究中，CBD 和 THC 的组合具有次加效应，而不是先前研究中报告的超加效应。由于 CBD 和 THC 组合产生的作用小于单独药物的总和 (1 + 1 > 2)，这可能表明这两种大麻素之间存在拮抗作用。

这项研究是在 EpLink（安大略脑研究所的癫痫研究计划）的支持下进行的。