Healthcare provider profile · identity verified

David Dakin Williams, M.D., PH.D.

Allopathic & Osteopathic Physicians|Psychiatry & Neurology|Psychiatry · MANCHESTER, NH · NPI 1346374998

Profile state: payments and partd Open Payments: 2025 Medicare Part D: 2024 Last identity check: 2026-08-10 Page data build: 2026-08-12

Verified facts

What the public records show

CMS Open Payments records show David Dakin Williams, M.D., PH.D. received $123.08 in general payments during 2025 across 7 reported records.

Lundbeck LLC accounted for 55.5% of that reported general-payment amount.

The Open Payments records used for this analysis explicitly named 4 associated products.

A separate comparison found the same explicitly named product in public Medicare Part D data: Rexulti.

Lundbeck LLC reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported REXULTI as an associated drug or biological on 71829 records involving 25812 distinct recipient NPIs. Public Medicare Part D data also shows 22 claims for Rexulti by this doctor in 2024.

These records do not establish that a payment influenced prescribing or medical care.

Payment overview · 2025

General Payments

$123.08

7 reported records · 4 companies

Separate record types

Research & Ownership

Research Payments (direct recipient): not present in the loaded data

Associated Research Funding (for example, named PI): not present in the loaded data

Ownership / Investment: not present in the loaded data

These categories are never added into the General Payments headline. Associated research funding must not be described as money the doctor personally received unless the source record supports that conclusion.

Who paid this doctor?

Companies in 2025 General Payments

Reported companyCanonical companyAmountShareRecordsYear
Lundbeck LLC Unresolved — no canonical attribution shown $68.3455.5%42025
Janssen Scientific Affairs, LLC Unresolved — no canonical attribution shown $26.2721.3%12025
Neurocrine BioSciences, Inc. Unresolved — no canonical attribution shown $14.3011.6%12025
Takeda Pharmaceuticals U.S.A., Inc. Unresolved — no canonical attribution shown $14.1711.5%12025

What were the payments for?

Payment categories

CategoryAmountRecords
Food and Beverage$123.087

A meal, consulting fee, royalty, and travel payment describe different kinds of reported relationships and should not be interpreted as equivalent.

Analysis 1 · Payment-linked products

Products named in Open Payments records

Reported productTypeReported companyRelated amount*RecordsYear
REXULTI
Normalized: rexulti
Drug Lundbeck LLC $68.34 4 2025
Source payment records
SPRAVATO
Normalized: spravato
Drug Janssen Scientific Affairs, LLC $26.27 1 2025
Source payment records
INGREZZA
Normalized: ingrezza
Drug Neurocrine BioSciences, Inc. $14.30 1 2025
Source payment records
TRINTELLIX
Normalized: trintellix
Drug Takeda Pharmaceuticals U.S.A., Inc. $14.17 1 2025
Source payment records

* Product-associated amounts are non-additive because one payment record may name more than one product.

These products were named on specific Open Payments records. A named product does not show that the payment influenced treatment or prescribing.

Public prescribing for products named in payments

Open Payments productPayment yearPart D brandPart D yearClaimsMatch methodSource
REXULTI
rexulti
2025 Rexulti 2024 22
Beneficiary count suppressed
exact normalized Medicare Part D

The presence of the same drug in both datasets does not show that a payment caused or influenced a prescription.

Analysis 2 · Same-company prescribing overlap

Drugs reported in other payments from the same company that also appear in Medicare Part D

This analysis is independent from products named on this doctor’s individual payment records. A row appears only when the exact Open Payments reporting entity paid this doctor, that same reporting entity reported the drug or biological on at least 10 loaded General Payment records involving at least 2 distinct recipient NPIs, and this doctor has the same non-generic brand in public Part D data. This does not mean the company owns or manufactures the drug.

Paying companyPayment yearDrug reported by same entityOpen Payments evidencePart DClaimsBeneficiaries
Lundbeck LLC
Exact reporting entity; no affiliate inference
2025 REXULTI
open payments reported associated product
CMS Open Payments — General Payments
71829 supporting records · 25812 recipient NPIs · example record 1251759986
Rexulti · 2024
Exact normalized brand match · 1 Part D row
22 suppressed by CMS

These facts do not show that a payment was for the drug, that the company owns or manufactures the drug, or that a payment caused or influenced prescribing.

Public Medicare Part D data

Provider-and-drug rows loaded for 2024

BrandGenericClaimsBeneficiaries
Bupropion XlBupropion Hcl8924
Trazodone HclTrazodone Hcl8827
Quetiapine FumarateQuetiapine Fumarate8117
Buspirone HclBuspirone Hcl6818
LorazepamLorazepam6118
Venlafaxine Hcl ErVenlafaxine Hcl55suppressed
Fluoxetine HclFluoxetine Hcl5413
Sertraline HclSertraline Hcl4812
RisperidoneRisperidone47suppressed
ClonazepamClonazepam46suppressed
Escitalopram OxalateEscitalopram Oxalate43suppressed
LamotrigineLamotrigine4111
Quetiapine Fumarate ErQuetiapine Fumarate40suppressed
Clonidine HclClonidine Hcl3911
AripiprazoleAripiprazole3811
AlprazolamAlprazolam37suppressed
Dextroamphetamine-AmphetamineDextroamphetamine/Amphetamine34suppressed
Divalproex Sodium ErDivalproex Sodium34suppressed
OlanzapineOlanzapine34suppressed
Zolpidem TartrateZolpidem Tartrate33suppressed
GabapentinGabapentin32suppressed
MirtazapineMirtazapine3213
Dextroamphetamine-Amphet ErDextroamphetamine/Amphetamine29suppressed
OxcarbazepineOxcarbazepine28suppressed
Bupropion Hcl SrBupropion Hcl27suppressed
RexultiBrexpiprazole22suppressed
Desvenlafaxine Succinate ErDesvenlafaxine Succinate21suppressed
Benztropine MesylateBenztropine Mesylate20suppressed
HaloperidolHaloperidol20suppressed
Hydroxyzine HclHydroxyzine Hcl19suppressed
Hydroxyzine PamoateHydroxyzine Pamoate19suppressed
Divalproex SodiumDivalproex Sodium17suppressed
Lamotrigine ErLamotrigine14suppressed
Prazosin HclPrazosin Hcl14suppressed
Paliperidone ErPaliperidone13suppressed
TopiramateTopiramate13suppressed
Citalopram HbrCitalopram Hydrobromide12suppressed

Timeline

Payment and prescribing data by year

Open Payments and Medicare Part D may refer to different years. They are shown separately rather than aligned as if they describe the same period.

YearGeneral PaymentsMain payerExplicit productsCompany overlapsPart D coverage
2025 $123.08 · 7 records Lundbeck LLC INGREZZA, REXULTI, SPRAVATO, TRINTELLIX 1
2024 Complete

Questions to ask

Questions you could discuss with your doctor

These are general questions generated from reviewed templates. They are not personalized medical advice.

Sources and limitations

How to read this page

Loaded source releases

DatasetYearPublicationSource
CMS Open Payments — General Payments 2025 2026-06-30 Original source
Medicare Part D Prescribers by Provider and Drug 2024 2026-05-06 Original source
NPPES Data Dissemination V2 current / reference data 2026-08-10 Original source

Methodology version: 2.1

Editorial template version: 2.4

Product contract version: 2.0

Schema version: 0.7.0

Page data build: 2026-08-12T23:34:59.370714+00:00

Publication policy: eligible for indexing after public-launch controls are enabled

Full methodology · Questions & answers · Report a possible error