General synonyms:
* Suspicious: This is a more neutral term, simply implying a lack of trust.
* Distrustful: Similar to "suspicious," but often with a stronger sense of doubt.
* Wary: Cautious and hesitant, often due to a sense of danger or threat.
* Apprehensive: Feeling anxious or fearful about something.
* Fearful: Feeling afraid or worried.
* Concerned: Having a feeling of worry or unease.
* Preoccupied: Obsessed with or focused on something to the exclusion of other things.
More specific synonyms:
* Delusional: Having false beliefs that are not based on reality.
* Psychotic: Suffering from a severe mental disorder that affects reality perception.
* Persecutory: Believing that others are trying to harm you.
* Hallucinatory: Experiencing sensory perceptions that are not real.
* Obsessive: Having persistent and intrusive thoughts or behaviors.
Informal synonyms:
* Jumpy: Easily startled or nervous.
* On edge: Feeling anxious or tense.
* Freaked out: Feeling extremely scared or overwhelmed.
The best synonym for "paranoid" will depend on the specific situation and the level of intensity you want to convey.