Seven days of CBD at high doses produced antidepressant effects in mice by increasing serotonin and noradrenaline

Only the high dose (100 mg/kg) produced antidepressant effects in the forced swim test after 7 days of administration. This dose significantly increased serotonin (5-HT) and noradrenaline (NA) in the hippocampus. Both 30 mg/kg and 100 mg/kg decreased NF-kB expression. No locomotor effects were observed at any dose, ruling out non-specific activity changes.

Male mice received synthetic CBD (30 or 100 mg/kg) or vehicle daily for 7 days. Behavioral assessment via forced swim test and open field test. Hippocampal serotonin and noradrenaline measured by HPLC-ECD. NF-kB, BDNF, and other proteins measured by RT-PCR and Western blot.

While acute CBD effects have been studied, chronic administration is more clinically relevant. Finding that CBD increases serotonin and noradrenaline, the same targets as conventional antidepressants, provides a mechanistic rationale for CBD in depression.

If CBD works through the same neurotransmitter systems as established antidepressants, it could potentially be an alternative or adjunct for patients who do not respond to or tolerate conventional medications.

Animal study with high CBD doses (100 mg/kg) that may not be achievable in humans. Only 7 days of treatment. Forced swim test is a simplified depression model. Synthetic CBD may differ from plant-derived CBD in some respects.