Lily Allen has learned to spot the signs when she is falling into a "bout of depression" and always books a month off work to deal with her emotional issues.
The British pop star has been seeing a therapist regularly ever since she suffered a miscarriage in 2008, but she is still plagued by "negative thoughts".
And the Smile singer, who has vowed to retire from pop this year (10), admits she always has a plan to make sure she isn't overwhelmed by her dark moods.
She tells Britain's Sky TV, "I work with a therapist on a regular basis. I'm quite capable of noticing when I'm taking a turn for the worse. Then I decide not to work for the next month, and I take time to concentrate on myself. I had to do that in January 2008 after my miscarriage.
"I haven't had to call my therapist recently but, if I felt there were repetitive negative thoughts going around in my head, I've had enough mental history to know to call someone for help. It's negative thoughts about the world and things going on around me, I can generally write that off as a temporary bout of depression. But if the negative thoughts are about me, then it gets a bit more serious."