When Michigan removed gabapentin from its controlled substance schedule in May 2024, prescribers responded quickly. A new study published in JAMA Network Open found that Medicaid dispensing rates jumped by 4 prescriptions per 1,000 enrollees almost immediately after the policy change — a statistically significant shift that mirrors what happened when the drug was first scheduled (prescribing dropped then, too).

Researchers used a controlled interrupted time-series design, comparing gabapentin dispensing trends against pregabalin — a drug with similar uses but no scheduling change — as a control. The analysis covered Michigan Medicaid data from early 2023 through mid-2025, offering a clear before-and-after picture of the policy's impact.

The findings point to a direct, reciprocal relationship between drug scheduling and prescriber behavior: tighten the rules, and doctors pull back; loosen them, and prescribing climbs.

By the Numbers

• 4.00 additional gabapentin prescriptions per 1,000 Medicaid enrollees immediately post-descheduling (95% CI: 2.33–5.67)
• Gabapentin dispensing ranged from 33–43 prescriptions per 1,000 enrollees throughout the study period
• No statistically significant change in the longer-term prescribing trend was detected

Why it matters: Gabapentin misuse is a growing concern, with the drug increasingly implicated in overdose deaths — often alongside opioids. This study suggests that scheduling policy is a meaningful lever for controlling use, and that removing restrictions can have fast, measurable consequences for public health.