One way to distinguish in a sentence whether a participle is describing the EXPERIENCER of the emotion or describing the SOURCE of it is to express the relationships in a simple "concept sentence." We can create a concept sentence for any -ed or -ing participle.
A concept sentence is a simple, one-clause sentence, written in active voice, in simple present tense. The verb in a concept sentence shows the action or emotion. Using subject-verb-object (SVO) order, the concept sentence illustrates the relationship that exists between SOURCE and EXPERIENCER (Bordman, Byrd, & Schlein, 1977).
For example, given the phrase "the frightened dog," we could generate a concept sentence:
Something (S, SOURCE) frightens (V) the dog (O, EXPERIENCER)
Something is frightening to the dog. (SOURCE/-ing)
The dog is frightened. (EXPERIENCER/-ed)
Given "depressing news":
Concept sentence: The news (SOURCE) depresses people (EXPERIENCER).
Alternative Expression: People are depressed about the news.
Given "a confusing report":
Concept sentence: The report (SOURCE) confuses the reader (EXPERIENCER).
Alternative Expression: The readers are confused.
Given "a frustrated citizen":
Concept Sentence: The new law (SOURCE) frustrates the citizen (EXPERIENCER).
Alternative Expression: The new law is frustrating.