Word Salad Finding the Right Words

In this public service announcement, a mother tries to talk to her daughter about drugs. She is unable to find the words, and so her speech comes out as a random collection of unrelated words.

Word Salad is a condition in which the speaker believes they are speaking clearly, but are in fact speaking in the gibberish-like manner presented in this clip. What are the causes of Word Salad? How can it be treated?