Jada Pinkett Smith has suffered "bouts of depression" despite her fame and success.
The 52-year-old actress - who is married to Hollywood star Will Smith - has revealed that she experienced "overwhelming" feelings of "hopelessness" around her 40th birthday.
In her new book 'Worthy' - an excerpt of which has been published by PEOPLE - Pinkett Smith shares: "For two decades, I had been putting on a good face, going with the flow, telling everyone I was okay.
"Yet underneath, bouts of depression and overwhelming hopelessness had smouldered until they turned into raging hellfire in my broken heart. Unwelcome feelings - of not deserving love - made it harder to understand the disconnect between the so-called perfect life I had achieved and the well of loss I carried with me.
"Therapy helped up to a point. It got me to forty! But to what end?"
Pinkett Smith admits that she was a "chronic mess" at one point in time.
The Hollywood star also described her kids as her "only motivation" to keep going.
Pinkett Smith - who has Jaden, 25, and Willow, 22, with Smith, while she's also the stepmother of Trey, her husband's son from a previous marriage - said: "I would later be diagnosed and informed that I suffer from complex trauma with PTSD and dissociation, but without this guidepost, I was a chronic mess with no fix, no possibility to heal.
"Every morning, waking up was like walking the plank of doom - could I make it to 4pm? If I could, I had survived the day. I always wanted to sleep, but I never slept well.
"My children could put a smile on my face and were my only motivation to keep me going, but more and more, I could feel myself losing my grip of connection to them."