Watching a video on the neuroscience of meditation, I see an explanation that the amygdala has two sides, one dealing with happiness and one dealing with fear. If the stimulation of the happiness side becomes intense enough then the activity spills over to the other side and activates fear. This is supposed to be the origin of the cycles of bliss and dark night.
Is this a well known explanation ?

I don't know if it's somehow related to meditation.

I just remember Brene Brown saying that there are studies showing that joyful events are likely to lead to relapses of depression, alcoholism etc.
Can't have one without the other obviously.

This might be the one you're thinking of:

https://www.youtube.com/watch?v=zqrpKUTMXgY

Wikipedia:

http://en.wikipedia.org/wiki/Amygdala#Hemispheric_specializations

That's the Jimmy, yes. I didn't want to dig through his videos again to find the exact bit but you've got it there. Murphy says that prolonged intense stimulation of the happy side can cause a spillover of neural activity into the dark side so I wonder if there is any other confirmatory work on this ?
He also says, if I remember, eventually this spillover can stop leaving a permanent enhanced connection to the happy side.
I wonder if I could ask him to stop by the forum and explain ?

Ultimately that would be the best, since he can give more details or point to other studies that back him up.

Another explanation from a psychodynamic perspective would be that many people (especially those prone to depression, abuse etc) also have a critical mental stance towards themselves and also states of pleasure, joy and happiness can in some cases trigger anxiety because of early relational history of being punished for having a good time. Translated into psychodynamics in adulthood, this means the persons own superego (internalised care-takers) moves to punish the person for feeling good/doing something good for themselves. This also then triggers anxiety.

No idea if this can account for any of the above mentioned relationships between the phenomenas of joy and anxiety, but wanted to add these thoughts also. (I'm a clinical psychologist so also the above is not only theoretical as it's also from experiences in therapy with people).

Hey Malte, I hope you stick around. You could probably add an interesting point of view here.

Thanks, I hope so too!