Scoring
Every item is scored on the same 1 (Strongly Disagree) to 5 (Strongly Agree) scale. Item 18 — "I'm fine spending a long stretch of time away from people I'm close to." — is worded in the opposite direction from the rest of the scale, so it's reverse-scored (1↔5, 2↔4, 3 stays the same) before totaling. This keeps a high number meaning the same thing across all 30 items: more separation anxiety, not less.
The 30 items split evenly into three subscales, ten items each:
Anticipatory Distress: items 1, 4, 7, 10, 13, 16, 19, 22, 25, 28 (raw score range 10–50)
Somatic & Cognitive Panic: items 2, 5, 8, 11, 14, 17, 20, 23, 26, 29 (raw score range 10–50)
Proximity Seeking: items 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 (raw score range 10–50)
Add up all 30 items for a total raw score somewhere between 30 and 150. Each subscale also gets converted to a 0–100 scale on its own, which makes it easier to see at a glance which pattern is driving someone's score.