The denial surge

Claim denials are rising across all of commercial insurance. Behavioral health starts from a worse baseline than the rest of medicine, and the 2025 data shows the gap widening further.

By mid-2024, a 14-clinician intensive outpatient program (IOP) in Colorado was running a 22% claim denial rate with its primary commercial payer, Aetna. That number had been 8% in 2021. Each denial cited "level of care not medically necessary," using criteria the practice asked for and never received. When the practice filed a comparative analysis request under MHPAEA, the Mental Health Parity and Addiction Equity Act, it found Aetna applying significantly stricter medical-necessity standards to behavioral health (BH) inpatient and partial care than to comparable medical or surgical inpatient levels of care. That gap is what regulators call a non-quantitative treatment limitation (NQTL) violation. The Department of Labor (DOL) has documented this exact pattern in multiple published enforcement findings.^[4]

That trajectory, 8% to 22% over three years, is not an outlier. Experian Health's 2025 State of Claims survey found that 41% of all providers now report denial rates above 10%, up from 30% in 2022, a rise of 11 percentage points.^[3] KFF's 2024 analysis of Centers for Medicare and Medicaid Services (CMS) transparency data found that ACA Marketplace in-network plans denied 19% of all claims submitted, 85 million of 451 million.^[1] Out-of-network? 37%.^[1]

Medicare Advantage (MA) is its own story. In 2024, payers denied 7.7% of the 53 million prior authorization (PA) requests submitted, up from 6.4% in 2023.^[2] The number that really stings: of the MA PA denials that were appealed, 80.7% were fully or partially overturned.^[2] Wrong more than four times out of five when someone pushed back. Most practices never push back.

Government-certified data on BH-specific denial rates at the CPT (Current Procedural Terminology) code level is not yet available. CMS has mandated that qualified health plans begin reporting that breakdown starting in 2027. Until then, the structural gap shows up in how often BH services land out-of-network, 5.2 times more often than primary care office visits in 2017 per FAIR Health data cited in DOL parity research,^[4] and in enforcement findings describing BH medical-necessity criteria applied at standards stricter than anything used for comparable medical care.

Two steps close the gap. First, track your denial rate by payer and by CPT code every month, not quarterly. A pattern visible at 30 days is actionable; one you find at 90 days has already cost you three months of revenue. Second, appeal every denial that does not cite a correctable administrative error. The overturn rate on appeal is high enough that a systematic workflow pays for itself inside a year.