In test with rats, cannabidiol showed sustained effects against depression for seven days -- ScienceDaily"The forced swim test is used to measure the effect of antidepressant drugs because all known antidepressants shorten the duration of immobility and hence lengthen swim time. A reduction in immobility time in this test is interpreted as 'antidepressant-like' behavior." The researchers found that cannabidiol induced acute and sustained antidepressant-like effects in mice submitted to the forced swim test. "However, to make sure this result isn't due to the increase in movement caused by a psychostimulant effect leading the animals to swim more vigorously, for example, we performed a separate test to control for locomotor activity," Joca explained. "To do this we used the open-field test, which consists of putting the animal in a novel arena and letting it explore the new environment freely while its locomotor and exploratory activity is recorded. A drug is said to have potential antidepressant effects if it reduces immobility time and increases swim time in the forced swim test without increasing locomotor activity in the open-field test, showing that the effects observed in the forced swim test aren't secondary to nonspecific alterations in locomotor activity."