These days I can switch on inner calm, but not all the time. The shit still hits the fan, but the difference is that in the past I could go over the edge, into depression. Now I can pull back. I’m not saying it couldn’t happen, but I haven’t had one in a while. I can see it before the tsunami starts to build. I either distract myself, or hold on and let all those negative thoughts wash over me; the loops in my mind that say: ‘You’re not good enough. You’re getting old. No one loves you.’

What we should all be aiming for is stable contentment, but who doesn’t like a buzz? The ones in trouble try to live their lives for the buzz. Rage is pretty much my drug of choice. I notice it coming and turn it around pretty quickly. I used to love getting angry, then I’d regurgitate the story of how someone did something to me, which made me more angry, and I know it just poisons me. My moods are more constant but if I need anger, I can access it. It’s just I’m addicted to it, so I have to watch it. There are still certain people you have allergies to, but I know if I ever attacked, I’d get a hangover the next day, so I back away.

I’m very alert to how I feel. That’s mindfulness. I’ve being doing it for the past 12 years; you let your thoughts come in, but you don’t get carried away by them.

I don’t embrace being the age I am (64), but I don’t think I’d be this smart if I was younger. I’m amazed I can write books. I wasn’t like this as a kid and if that’s not about neuroplasticity, then what is? What I’ve learned is that your brain can keep on changing; you really can work those muscles. Now I’m just hungry. Hungry to keep stretching my brain, for more knowledge. I think I’m at my peak. It used to feel like a scary place in my brain, but now it’s fun.

How To Be Human. The Manual by Ruby Wax (Penguin Life, £14.99) or £12.74 at guardianbookshop.com