Scientists are still discovering the many layers of changes that take place in response to chronic stress — but they include both the brain’s structure and chemistry. Certain regions of the brain become hyperactive, while others atrophy and even shrink, and levels of neurotransmitters (like serotonin, dopamine and endocannabinoids) and their receptors also change.  
CBD oil and cannabis oil are both known to reduce the symptoms and side effects of cancer. The presence of both THC and CBD helps in treating the pain associated with cancer. According to research done by Hansen M., Medical University of Vienna, Vienna, Austria, it also treats the side effects of chemotherapy including nausea, vomiting, and anxiety.
It is also illegal to market CBD oil as a dietary supplement.  This is because cannabidiol is not a food ingredient (dietary ingredient) and it doesn’t have an established safety profile or history of use in the food supply. If you see a CBD product, and it is labelled as a dietary supplement, then the company is either unaware or doesn’t care about the FDA’s current position that CBD is not a legitimate dietary ingredient.
I recently was a guest at a medical marijuana educational event that highlighted the work of researcher Michael Backes. During his presentation he made a statement about CBD that I have never heard anywhere else that CBD is “regulating” (my word) the effects of THC. I asked the Nurse Practitioner at the event, Ivy Lou Hibbitt of, what he meant by that and she said it was her understanding of Michael’s comment that he takes CBD to reduce the psychoactive effects of THC. Has this property of CBD, that it can lessen psychoactive effects, ever been researched elsewhere?
Some users speculate about appropriate dosages or methods of application—including whether or not a small amount of THC boosts CBD’s effects, or whether different methods of administration lead to quicker or more significant effects. Some CBD producers also claim that it has a cumulative effect, and so needs to be used regularly to produce a benefit. But Grant says it’s tough to say at this point exactly how people should (or shouldn’t) be using CBD.
For this study, 24 people with social anxiety disorder received either 600 milligrams (mg) of CBD or a placebo an hour and a half before performing a simulated public speaking test. Additionally, 12 other people with social anxiety disorder performed the same test without receiving any CBD treatment. Results revealed that pre-treatment with CBD significantly reduced anxiety, cognitive impairment, and discomfort while participants were delivering their speech.
Sub-lingual CBD drops have helped me enormously with sleeping and with radiation damage pain. I have a cancer that spread from the pelvic area to my sacrum and sciatic nerve and whilst the chemo and radiotherapy saved my life I have been taking MST (morphine derivative) for nerve pain ever since. My tumours are presently all quiet and last March I decided I wanted to stop taking the pain relief drugs, fearing dementia. CBD oil was recommended by my son who has arthritis and, for me, it really works. It’s so good to read an article that isn’t put out by a CBD sales site – I wish it could be properly prescribed and regulated (I’m in the UK) in order to have confidence with purity and dosage.
Serotonin: Most people associate serotonin with happiness. However, the role of this neurotransmitter is very complex, and its effects depend on where it is and what it binds to. (Contrary to popular belief, more serotonin is not necessarily better — dysfunction can stem from low or high levels of serotonin, as well as from malfunctions with their receptors.) Serotonin has at least 14 different receptors, but CBD specifically binds to 5-HT1A which is thought to have the strongest role in anxiety disorders. The anti-anxiety drug buspirone also binds to this particular receptor, which explains the anti-anxiety effects of CBD on rats exposed to stressful situations.

Marijuana can produce acute psychotic episodes at high doses, and several studies have linked marijuana use to increased risk for chronic psychosis in individuals with specific genetic risk factors. Research suggests that these effects are mediated by THC, and it has been suggested that CBD may mitigate these effects.xxxi There have been a few small-scale clinical trials in which patients with psychotic symptoms were treated with CBD, including case reports of patients with schizophrenia that reported conflicting results; a small case study in patients with Parkinson’s disease with psychosis, which reported positive results; and one small randomized clinical trial reporting clinical improvement in patients with schizophrenia treated with CBD.xxxii Large randomized clinical trials would be needed to fully evaluate the therapeutic potential of CBD for patients with schizophrenia and other forms of psychosis.