Here's why:
* Verb: "Suffer" is the base verb, meaning to experience pain, hardship, or loss.
* Past Participle: "Suffered" is the form used to indicate a completed action in the past.
While "suffered" can be used as part of a verb phrase (e.g., "He has suffered a lot"), it can also act as an adjective describing a state or condition (e.g., "She had a suffered expression").