The endocannabinoid system somehow plays a part in helping the body with different kinds of stress related issues, one of them being depression.

I haven't had a chance to read all of the text, but what it sounds like is that a dysfunction in the EC system has been linked to people suffering from depression.

In other words, when the body fails to produce the chemicals it needs to operate efficiently, you need to get them from an outside source.

Here's some articles for you to check out:

Endocannabinoid System Can Be Targeted For New Pharmaceuticals To Treat Depression

A possible role for the endocannabinoid system in the neurobiology of depression

Role of endocannabinoid system in mental diseases


For myself I've found that mostly indica strains are best to make me happy, as the dominant sativas can make me feel happier too they can also get my mind racing and overthinking ANY of the things that are already on my mind which can be negative.