The overarching purpose of the Nielson lab is to understand and treat trauma. Research projects in the Nielson lab utilize a multidisciplinary approach, merging the fields of neurobiology, psychiatry and informatics to identify more precise "bio-types" of trauma psychopathology than traditional diagnostic criteria, and potential novel targets for treatment. We use established and emerging machine learning methods with multi-modal data spanning across a diverse range of diagnostic categories for neuropsychiatric disorders. Our approach can be used to run hypotheses on in silico models to understand the complexity involved in these disorders. An advantage of such approaches is the minimization for the need to test hypotheses in animal models (in vivo). Dr. Nielson received an Early Stage Investigator (ESI) award from NIMH to apply these methods to large datasets from trauma-exposed patients to identify and validate dimensions of post-traumatic stress (PTS), relevant biological predictors, and precision treatment response trajectories.

Other areas of focus in the Nielson lab are dedicated to psychedelic neuroscience research and drug policy reform. Dr. Nielson has been collecting data through an anonymous online survey to assess benefits and risks of ayahuasca use in naturalistic settings to treat symptoms of trauma. Dr. Nielson is also conducting research into the neurological mechanisms of altered states of consciousness and their role in promoting neuroplasticity and wellness in healthy research participants. This work is funded by the newly created Psychedelic-Assisted THerapy (PATH) Fund through the UMN Foundation, which was created thanks to a generous donation from the local community. These, and other data, are part of a larger network of data supporting the potential for psychedelic therapies and experiences to promote wellness across a diverse range of mental health disorders (see network below). 

Donate to the PATH Fund!


Mental Health Informatics Research

Recent efforts to optimize diagnosis and treatment planning for psychiatric disorders through the Research Domain Criteria (RDoC) and ongoing clinical trials have generated large datasets housed in the NIMH Data Archive (NDA). The NDA is a valuable resource for data-driven discovery in mental health research. Data across multiple units of measure from a wide array of disorders are housed in the NDA. We will mine data from the NDA to characterize biotypes that span across diagnostic categories, and the complex constellation of symptoms and functional deficits that can be measured in individual patients.

Current research projects include combining dimension reduction, causal inference analyses, machine learning and topological data analysis (TDA) to characterize subtypes and predictors of syndrome trajectories and treatment response.

Current datasets include:

1) De-identified data from the NIMH Data Archive (NDA)

  • Contains data from clinical research on a wide range of mental health disorders for transdiagnostic and precision treatment research (N > 360,000).
  • Standardized data can be queried across multiple domains for clinical/phenotype, neurophysiology, imaging, genomics, disorder-specific assessments and completed treatment trials.
  • UMN IRB approval on May 1, 2018: STUDY00003370

2) De-identified data from the Federal Interagency on Traumatic Brain Injury Research (FITBIR) Informatics System

  • Contains data from clinical research on traumatic brain injury in children and adults (N>63,000).
  • Standardized data can be queried across multiple domains for clinical/phenotype, neurophysiology, imaging, domain-specific assessments and completed treatment trials.
  • UMN IRB approval on May 1, 2018: STUDY00003370

3) De-identified data from the National Institute of Drug Abuse (NIDA) Data Repository

  • Data from ~ 26,000 patients enrolled in NIDA-funded clinical trials
  • Outcomes include substance use, health measures and neuropsychiatric outcomes collected over time in a variety of patient populations struggling with substance abuse.
  • UMN IRB approval on May 1, 2018: STUDY00003370

4) Data from an anonymous online survey to assess the therapeutic uses of the plant medicine ayahuasca.

  • Contains structured data from questionnaire-based assessments related to symptoms of trauma, including PTSD, substance use, and depression.
  • Contains unstructured data from open-ended responses describing dangerous, beneficial and general experiences associated with ayahuasca use.
  • Collected under UCSF IRB #16-19906, approved for reuse/transferred to UMN IRB RNI00004357

5) Neurotrauma datasets from animal models and de-identified observational clinical studies assessing complications associated with trauma exposure.

  • Preclinical (animal models) spinal cord injury (SCI) data from the Open Data Commons for SCI (ODC-SCI)
  • De-identified observational data from patients with post-traumatic stress disorder (PTSD), monitoring cardiovascular health during disease progression from the Mind Your Heart (MYH) study.

6) De-identified data from cognitive training interventions for schizophrenia

  • Assessments before and after training for cognitive and symptom changes
  • ELISA data from serum samples before and after training for blood-based biomarker discovery

7) De-identified data from the The National Survey on Drug Use and Health (NSDUH).

  • NSDUH contains data about the use of illegal drugs, alcohol, and tobacco, diagnosed mental disorders and related treatments within the U.S. population, ages 12 or older.  
  • Data tables available from 1979 to 2016.

8) De-identified data from the Hazelden Betty Ford Foundation in Center City, MN

  • The lab has begun a collaboration with the Center City location to receive data from ~ 20,000 people who have received treatment for substance use disorders over the past 10 years
  • Data include medical history, treatment options, and long term follow up of SUD-related outcomes.
  • Our lab will focus on identifying trauma history risk factors for recovery and relapse trajectories.
  • UMN IRB approval on May 1, 2018: STUDY00003370

9) Visual surround suppression and perceptual expectation under psilocybin - enrollment starting in Spring 2021

  • FDA approval on January 2, 2020: IND #146989
  • UMN IRB approval on August 14, 2020:  STUDY00009765/SITE00000856/Pro00045074


The figure below illustrates a data-driven hypothesis that was found regarding functional decline in patients with PTSD following traumatic brain injury (TBI). Using a machine learning method known as topological data analysis (TDA), a gene involved in DNA repair was uncovered to have predictive value on functional outcome trajectories in a subgroup of patients with co-morbid PTSD and mild TBI.



Figure Legend. Network topology of patients with traumatic brain injury differentiates severity of brain pathology measured by both CT (A) and MRI (B), where most patients with a PTSD diagnosis 6 months (C) after injury have little to no obvious brain pathology (circled nodes). Highlighted patients show a decline in function between 3 (D) and 6 months (E) after injury, which was significantly predicted by enrichment for the A/T genotype of the PARP1 SNP (F, green nodes), a gene involved in DNA repair. Published in Nielson et al., 2017, PLoS One.


Psychedelic Research

Psychedelic research is undergoing a renaissance within the scientific arena, where an astounding volume of literature and data are emerging to support this new frontier in science and medicine. There is also increasing attention being paid in the popular press towards their therapeutic potential, including notable mediums like The New Yorker, NY Times, and Rolling Stone. Additionally, compounds such as MDMA and psilocybin have recently been granted breakthrough therapy designation by the FDA for PTSD and depression, respectively, making this area of research an exciting and innovate avenue for continued scientific exploration into their mechanisms of action. 

Psychedelic research in my lab focuses on collecting data from completed and ongoing psychedelic research studies to develop an evidence base for drug policy reform and treatment planning, as well as to understand the mechanisms for how these compounds inform new models about information processing in the human brain. Current projects include analysis of data from an anonymous online survey of ayahuasca users in naturalistic settings, and investigating the role of the 5HT2A receptor on neural mechanisms related to visual perception and expectations.

The network below is a model of overlapping symptoms of trauma, and various psychedelic therapies that have published research (red numbers and reference list) suggesting a therapeutic benefit.


Psychedelic Therapy Network


References for psychedelic therapy network


1. LSD, psilocybin or MDMA for end of life anxiety

Serotonergic hallucinogens in the treatment of anxiety and depression in patients suffering from a life-threatening disease: A systematic review

Pilot Study of Psilocybin Treatment for Anxiety in Patients With Advanced-Stage Cancer

Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases

LSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects

Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial

Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial

Individual Experiences in Four Cancer Patients Following Psilocybin-Assisted Psychotherapy

Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer

Acute and Sustained Reductions in Loss of Meaning and Suicidal Ideation Following Psilocybin-Assisted Psychotherapy for Psychiatric and Existential Distress in Life-Threatening Cancer

MDMA-assisted psychotherapy for treatment of anxiety and other psychological distress related to life-threatening illnesses: a randomized pilot study


2. LSD and psilocybin for migraine and cluster headaches

Response of cluster headache to psilocybin and LSD

Indoleamine Hallucinogens in Cluster Headache: Results of the Clusterbusters Medication Use Survey

Psychoactive substances as a last resort—a qualitative study of self-treatment of migraine and cluster headaches

Exploratory Controlled Study of the Migraine-Suppressing Effects of Psilocybin


3. Psilocybin for depression

Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study

Psilocybin for treatment-resistant depression: fMRI-measured brain mechanisms

Quality of Acute Psychedelic Experience Predicts Therapeutic Efficacy of Psilocybin for Treatment-Resistant Depression

Increased amygdala responses to emotional faces after psilocybin for treatment-resistant depression

Psilocybin with psychological support for treatment-resistant depression: six-month follow-up

Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression

Psilocybin-assisted group therapy for demoralized older long-term AIDS survivor men: An open-label safety and feasibility pilot study

Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression

Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial

Trial of Psilocybin versus Escitalopram for Depression


4. Ayahuasca for depression

Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report

Antidepressant Effects of a Single Dose of Ayahuasca in Patients With Recurrent Depression: A SPECT Study

Cortisol Modulation by Ayahuasca in Patients With Treatment Resistant Depression and Healthy Controls

Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial

Therapeutic potential of ayahuasca in grief: a prospective, observational study

Rapid and sustained decreases in suicidality following a single dose of ayahuasca among individuals with recurrent major depressive disorder: results from an open-label trial


5. Ayahuasca for addiction

Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada

Therapeutic effects of ritual ayahuasca use in the treatment of substance dependence--qualitative results.

Effects of Ayahuasca and its Alkaloids on Drug Dependence: A Systematic Literature Review of Quantitative Studies in Animals and Humans.

Short-Term Treatment Effects of a Substance Use Disorder Therapy Involving Traditional Amazonian Medicine


6. Ayahuasca for PTSD

Ayahuasca as a Candidate Therapy for PTSD

A Qualitative Assessment of Risks and Benefits of Ayahuasca for Trauma Survivors


7. Ibogaine for addiction

Ibogaine: Complex Pharmacokinetics, Concerns for Safety, and Preliminary Efficacy Measures

Noribogaine reduces nicotine self-administration in rats

Oral noribogaine shows high brain uptake and anti-withdrawal effects not associated with place preference in rodents

Ibogaine treatment outcomes for opioid dependence from a twelve-month follow-up observational study

Treatment of opioid use disorder with ibogaine: detoxification and drug use outcomes


8. Psilocybin for addiction

Pilot Study of the 5-HT2AR Agonist Psilocybin in the Treatment of Tobacco Addiction

Psilocybin-assisted treatment for alcohol dependence: A proof-of-concept study

Psilocybin-occasioned Mystical Experiences in the Treatment of Tobacco Addiction

Long-term Follow-up of Psilocybin-facilitated Smoking Cessation

Clinical Interpretations of Patient Experience in a Trial of Psilocybin-Assisted Psychotherapy for Alcohol Use Disorder

The Psychedelic Debriefing in Alcohol Dependence Treatment: Illustrating Key Change Phenomena through Qualitative Content Analysis of Clinical Sessions

Psychedelic therapy for smoking cessation: Qualitative analysis of participant accounts


9. Psilocybin for OCD

Safety, Tolerability, and Efficacy of Psilocybin in 9 Patients With Obsessive-Compulsive Disorder

Psilocybin and Obsessive Compulsive Disorder

Long-term Amelioration of OCD Symptoms in a Patient with Chronic Consumption of Psilocybin-containing Mushrooms


10. MDMA for PTSD

MDMA-assisted psychotherapy using low doses in a small sample of women with chronic posttraumatic stress disorder

The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study

A randomized, controlled pilot study of MDMA (±3,4-Methylenedioxymethamphetamine)-assisted psychotherapy for treatment of resistant, chronic Post-Traumatic Stress Disorder (PTSD)

Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study

Therapeutic effect of increased openness: Investigating mechanism of action in MDMA-assisted psychotherapy

MDMA-assisted psychotherapy for post-traumatic stress disorder in military veterans, firefighters, and police officers: a randomised, double-blind, dose-response, phase 2 clinical trial

Long-term follow-up outcomes of MDMA-assisted psychotherapy for treatment of PTSD: a longitudinal pooled analysis of six phase 2 trials

Posttraumatic Growth After MDMA-Assisted Psychotherapy for Posttraumatic Stress Disorder

MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study


11. MDMA for social anxiety in autistic adults

MDMA-assisted therapy: A new treatment model for social anxiety in autistic adults

Reduction in social anxiety after MDMA-assisted psychotherapy with autistic adults: a randomized, double-blind, placebo-controlled pilot study.


12. Cannabidiol for Dravet's syndrome

Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial

Trial of Cannabidiol for Drug-Resistant Seizures in the Dravet Syndrome


13. Marijuana for PTSD

On Disruption of Fear Memory by Reconsolidation Blockade: Evidence from Cannabidiol Treatment

Δ9-Tetrahydrocannabinol alone and combined with cannabidiol mitigate fear memory through reconsolidation disruption

Cannabidiol Regulation of Learned Fear: Implications for Treating Anxiety-Related Disorders

Cannabidiol regulation of emotion and emotional memory processing: relevance for treating anxiety‐related and substance abuse disorders

Preliminary, Open-Label, Pilot Study of Add-On Oral Δ9-Tetrahydrocannabinol in Chronic Post-Traumatic Stress Disorder

PTSD Symptom Reports of Patients Evaluated for the New Mexico Medical Cannabis Program

Blunted stress reactivity in chronic cannabis users

Cannabinoid modulation of corticolimbic activation to threat in trauma-exposed adults: a preliminary study

The short-term impact of 3 smoked cannabis preparations versus placebo on PTSD symptoms: A randomized cross-over clinical trial


14. Ketamine for depression (in progress, many trials on this)

Augmentation of response and remission to serial intravenous subanesthetic ketamine in treatment resistant depression

The Effect of Repeated Ketamine Infusion Over Facial Emotion Recognition in Treatment-Resistant Depression: A Preliminary Report

Ketamine for Rapid Reduction of Suicidal Thoughts in Major Depression: A Midazolam-Controlled Randomized Clinical Trial

Persistent antidepressant effect of low-dose ketamine and activation in the supplementary motor area and anterior cingulate cortex in treatment-resistant depression: A randomized control study

Intravenous ketamine infusion for a patient with treatment‐resistant major depression: a 10‐month follow‐up

Impact of oral ketamine augmentation on hospital admissions in treatment-resistant depression and PTSD: a retrospective study

Efficacy, Safety, and Durability of Repeated Ketamine Infusions for Comorbid Posttraumatic Stress Disorder and Treatment-Resistant Depression

Does oral administration of ketamine accelerate response to treatment in major depressive disorder? Results of a double-blind controlled trial.

Efficacy and Safety of Flexibly Dosed Esketamine Nasal Spray Combined With a Newly Initiated Oral Antidepressant in Treatment-Resistant Depression: A Randomized Double-Blind Active-Controlled Study

Esketamine Nasal Spray for Rapid Reduction of Major Depressive Disorder Symptoms in Patients Who Have Active Suicidal Ideation With Intent: Double-Blind, Randomized Study (ASPIRE I)

Efficacy of Intravenous Ketamine in Adolescent Treatment-Resistant Depression: A Randomized Midazolam-Controlled Trial

Esketamine Nasal Spray Plus Oral Antidepressant in Patients With Treatment-Resistant Depression: Assessment of Long-Term Safety in a Phase 3, Open-Label Study (SUSTAIN-2)

Efficacy and safety of adjunctive therapy using esketamine or racemic ketamine for adult treatment-resistant depression: A randomized, double-blind, non-inferiority study

Ketamine for acute suicidal ideation. An emergency department intervention: A randomized, double-blind, placebo-controlled, proof-of-concept trial


15. Ketamine for PTSD

Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic

Impact of oral ketamine augmentation on hospital admissions in treatment-resistant depression and PTSD: a retrospective study

Efficacy, Safety, and Durability of Repeated Ketamine Infusions for Comorbid Posttraumatic Stress Disorder and Treatment-Resistant Depression

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder


16. MDMA for addiction

First study of safety and tolerability of 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy in patients with alcohol use disorder: preliminary data on the first four participants

First study of safety and tolerability of 3,4-methylenedioxymethamphetamine-assisted psychotherapy in patients with alcohol use disorder


17. Ketamine for addiction

A Single Ketamine Infusion Combined With Mindfulness-Based Behavioral Modification to Treat Cocaine Dependence: A Randomized Clinical Trial

Ketamine can reduce harmful drinking by pharmacologically rewriting drinking memories