The moderate dose of CBD (30 mg/kg) increased HIP BDNF expression and rescued amphetamine-induced damage (possibly due to its effects as an anti-oxidant) when given after amphetamine exposure, whereas CBD pre-treatment had no effect on BDNF expression in the HIP, showing a protective effect of CBD on the biochemical changes associated with this model of bipolar disorder, only when administered post-treatment (40). Here, OPN1MW is linked to bipolar disorder.