The Potential Use of CBD for Depression Treatment

As a leading cause of disability, depression affects 322 million people worldwide. The disorder is characterized by a depressed mood and inability to experience pleasure, accompanied by sleep, eating, and mood disorders, and in more severe cases, suicidal thoughts [1]. Almost all available antidepressants act by increasing serotonin levels in the brain to increase the neuroplasticity, which is an essential and fundamental mechanism of neuronal adaptation that is disrupted in depression. These current antidepressants face challenges in terms of slow onset, single-modal mechanism, and partial or non-responses in nearly half of depression patients [1]. More effective medications with new mechanisms of action are needed to overcome the limitations of the current available antidepressants. CBD has the potential for being a new treatment option for depression with its complex pharmacology and the ability to interact with multiple neurotransmitter systems involved in depression.

Increasing evidence suggested that CBD promotes both a rapid and a sustained antidepressant effect in animal models [1]. In 2010, a group of scientists from Brazil first demonstrated that CBD is an antidepressant in animal models, a finding confirmed by multiple animal studies afterwards [2–14]. The potential mechanisms underlying CBD's antidepressant effects involve multiple neurotransmitter systems, including serotonergic, glutamatergic, and endocannabinoid systems, which play important roles when dealing with stress and depression. CBD promotes stress-coping behavior and resilience to chronic stress by modulating several pharmacological targets involved in the neurobiology of depression, regulating neurotransmission, and increasing functional neuroplasticity and cognitive flexibility [1]. Another study showed that chronic stress reduced the production of endocannabinoids, which are brain-produced cannabinoids that are involved in establishing and maintaining human health, resulting in depression-like behavior in animal models. Cannabinoids may restore normal endocannabinoid function and potentially help stabilize moods and alleviate symptoms of depression [15].

THC has also been reported to have antidepressant effects in animal models [3, 16] and in sub-euphoric doses in humans [17]. However, there are no randomized clinical trials published studying the effects of CBD or THC in depression in humans. Clinical studies are needed to investigate the potential antidepressant effect of cannabis, THC, and CBD as new medications, or in combination with available anti-depressants, for the treatment of depression.

Reference

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