A study of 129,287 adults found that people whose first sleeping pill prescription covered a month were twice as likely to still be filling it 7 years later. Most patients got that month.
Most people who get a prescription for a sleeping pill think of it as a short fix for a bad stretch of nights. Zolpidem, sold as Ambien, and its close relatives eszopiclone and zaleplon are the most commonly prescribed insomnia drugs in the United States, and they carry known risks of dependence and fractures. Researchers at the University of Southern California and Northwestern University followed 129,287 American adults for eight years after their first fill. They wanted to know whether one small decision made in the doctor’s office, how many days that first bottle covers, had anything to do with who was still filling these drugs years later.
How the first prescription was measured
The team used Optum’s insurance claims database, which covers people with large commercial plans and Medicare Advantage, from 2007 to early 2024. Everyone in the study was an adult starting a Z-drug fresh, with at least a full year of no Z-drug fills beforehand, and everyone stayed enrolled for at least eight years afterward. Their average age was 58.7, and 59.3% were women.
The researchers sorted patients by the number of days their first prescription covered: 1 to 14 days, 15 to 24, 25 to 34, or 35 and more. The month-long option dominated. 70.3% of patients started with a 25 to 34 day supply, while only 13.9% got two weeks or less. The average first prescription covered 27 days.
They adjusted their estimates for age, sex, education, income, net worth, insurance type, region, and whether patients had been diagnosed with insomnia, anxiety, or depression in the year before the first fill. They also left out the year of the first prescription itself, so that first bottle could not count toward later use.
Seven years later
In the first year after the starting year, 15.6% of patients who began with two weeks or less filled another Z-drug prescription. That rose to 25.1% for 15 to 24 days, 38.1% for the month-long supply, and 49.5% for 35 days or more. Comparing the month-long group with the shortest group, the adjusted gap was 22.4 percentage points.
The gap shrank over time but never closed. Seven years on, 7.9% of the shortest group were still filling Z-drug prescriptions, compared with 11.5%, 15.6%, and 18.9% in the longer groups. People who started with a month’s supply were about twice as likely as those who started with two weeks to still be filling these drugs, with an adjusted difference of 7.6 percentage points.
The amount of medication followed the same pattern. In the first year, the month-long group filled 42.8 more days’ worth of pills than the shortest group. In the seventh year, they still filled 17 more days. They were also more likely to fill at least a 180-day supply in a single year, a level that points to near-nightly use.
“The first prescription may play an important role in shaping long-term use of sleep medications,” lead author Jonathan Cloughesy said in a statement.
What the study cannot show
The study does not show that a longer prescription causes long-term use, and the authors say so directly. Doctors did not assign prescription lengths at random. They may have written longer prescriptions for patients with more severe or chronic insomnia, who would have kept using sleeping pills anyway. The adjustment for prior insomnia, anxiety, and depression diagnoses captures some of that difference, but not all of it.
Claims data record when a prescription was filled, not whether the pills were taken. The eight-year enrollment requirement may also have shaped the results. If the heaviest users in the longer-supply groups were more likely to die or lose coverage, they dropped out of the data, and the true long-term gap could be larger than reported. The sample came from commercial and Medicare Advantage plans, so the findings may not apply to people on Medicaid or without insurance.
Why the first bottle might matter
The researchers modeled their question on a pattern already documented with opioids, where the size of the first prescription is linked to how often patients become long-term users. Z-drug prescriptions often run longer than clinical guidelines recommend, and the pills sit on the nightstand for as long as the bottle lasts.
The authors suggest that changes to the default prescription length in electronic health record systems, the menu a doctor clicks when writing an order, deserve study. Some of the same researchers are already running a randomized trial of such nudges in primary care, which could answer the cause-and-effect question this study cannot.
The study was funded by the National Heart, Lung, and Blood Institute. The authors reported no conflicts related to the study. The only disclosures were grants, fees, and advocacy roles outside the submitted work, including one author’s unpaid board seat at Physicians for Responsible Opioid Prescribing.
Source
Cloughesy JN, Thunell J, Liu X, Persell SD, Linder JA, Sullivan MD, Doctor JN. “Initial Z-Drug Prescription Duration and Long-Term Use.” JAMA Network Open, 2026.
DOI: 10.1001/jamanetworkopen.2026.32006
