Brandy is convinced tragic star Whitney Houston sank into a dark place when she lost her powerful vocal abilities, insisting, "It probably drove her insane."

The I Will Always Love You legend's career nosedived when she began to experience vocal problems, thought to be the result of substance abuse, and Brandy believes her pal was driven to despair when she couldn't hit the high notes at her final concerts.

She tells CNN newsman Piers Morgan, "I understand what that feels like. I don't understand to that degree, but I understand, you know, because I feel like when I don't have my instrument, I don't really have me... It's almost who you are. Of course, there's more to you than your voice, but that's what you use to share. That's what you use to give. It's your purpose. It's what you were born to do... It probably drove her insane (when it faltered). It probably drove her insane."

Brandy reveals she is still dealing with feelings of regret for not spending much time with her pal before her sudden death in February (12).

She adds, "One of the things that I can't put my mind around is where she really was because at the end of her life, I wasn't there. I wasn't around. I didn't talk to her as much, which is one of the reasons why it was so hard for me to get over her passing, is because I felt like I wasn't there enough for her at the end of her life. And I have no clue where she was mentally or spiritually."

Brandy also admits her brother Ray J, who was Whitney Houston's on/off boyfriend, is still struggling to cope with the loss, adding, "They were really close friends... Ray has been going through (difficulty). He really has been going through it. But, you know, every time we go through something, we always stick to who we are as family. And you know, so we've been there for him. But he's been silent about everything and, you know, just taking his time with it... (A) very tough thing to deal with."