A Phase 2 interventional study of Pimavanserin 34 mg and Placebo in Intermittent Explosive Disorder, sponsored by Ohio State University. Recruiting at 1 site in United States. Open to participants aged 21 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-03-27.
Sponsored by Ohio State University · Phase 2, Interventional, and Basic science
The investigators are studying how certain drugs can reduce anger outbursts in people with anger problems. In this study the investigators seek to determine if a single 34 mg (two 17 mg tablets) oral dose of the 5-HT2a receptor blocker, pimavanserin, will reduce aggressive responding in individuals with impulsive aggression (Intermittent Explosive Disorder: IED) on a laboratory task that assesses aggression (Taylor Aggression Paradigm: TAP). We will also be examining how this drug impacts hostile social cognition e.g., hostile attribution). If pimvanserin reduces aggression in this study a next step would be a placebo-controlled treatment trial of pimavanserin in study participants with IED. Participation will first involve a remote (e.g., TEAMS) screening session. If potential study participants appear eligible they will come into the lab for an in-person session where participants will complete interviews and questionnaires and have a medical evaluation (including a physical exam, electrocardiogram, and screens for alcohol and drug use). During the next study session, participants will complete a diagnostic interview and a series of questionnaires, all of which can all take place on-line. During the next two sessions (which will be in-person) participants will undergo two (2) study sessions during which study participants will be given a study drug (orally). The drug given, pimavanserin, is currently available and is known to block serotonin receptors thought to be involved in regulating anger. After participants take the study drug, study participants will complete questionnaires and computer tasks for assessment of aggression and of hostile social cognition. Each of these two in-person study sessions will take at least eight (8) hours. A final on-line session will be done to make certain the investigators have all the data required by the study protocol.
Human aggression is verbal and/or physical behavior directed at others (or objects) that results in injury to others (or objects). It is at the core of much human suffering and it is quite common. About four percent of the U.S. population have recurrent "anger attacks" and meet lifetime criteria for Intermittent Explosive Disorder (IED), a disorder of recurrent, problematic, impulsive aggression. In addition, another four percent of individuals have recurrent "anger attacks" that may not fully meet DSM-5 criteria for IED. Neurochemical brain studies have pointed to a modulatory role in human aggression for a variety of central neurotransmitters, particularly serotonin (5-HT). Evidence for a role for 5-HT in aggressive and suicidal behavior has been in the human literature since the late 1970s. Cerebrospinal fluid (CSF) levels of 5-HT metabolites (5-HIAA) have been reported as low in violent suicidal behavior and in those who have committed seriously aggressive acts such as homicide or attempted homicide. In addition, hormonal responses to 5-HT agonists are blunted in aggressive individuals and are inversely correlated with measures of aggression and suicidal behavior. Relevant to this proposal are data which report that the number of brain 5-HT-2a receptors are increased in those who had committed suicide by violent means and that brain and platelet 5-HT-2a receptors correlate in a positive direction with measures of aggression. In addition, similar findings have been reported regarding the PET neuroimaging of 5-HT-2a receptors in aggressive individuals. While stimulation of most 5-HT receptors increase behavioral inhibition, stimulation of 5-HT-2a receptors appear to do the opposite. If so, we hypothesize that blocking 5-HT-2a receptor activity with a 5-HT-2a receptor blocker will reduce aggressive responding in aggressive individuals. In this study, we propose to give a single dose of pimavanserin (and placebo on another day) and have aggressive individuals complete an analogue computer task of "aggressive responding". Because aggression is highly related to hostile social cognition, we will also have study participants complete a social cognition task to test the related hypothesis that pimavanserin can also reduce hostile social cognition. This project is designed to be an experimental medicine study to test the potential anti-aggressive efficacy of pimavanserin, a selective inverse agonist and antagonist of the serotonin 5-HT-2a receptor. As such, it is an early "proof of concept" study before, and without the expense of, conducting a clinical treatment trial.
Hypotheses of the study.
56 studies on the registry are indexed under Disruptive, Impulse Control, and Conduct Disorders; 17 are open to participants now.
This study's planned enrollment of 35 is below the median of 48 across 46 interventional studies indexed under Disruptive, Impulse Control, and Conduct Disorders.
Browse Disruptive, Impulse Control, and Conduct Disorders studies →Ohio State University is the lead sponsor of 663 studies on the registry; 148 are open to participants now.
Of its 67 completed or terminated interventional studies of FDA-regulated products, 49 (73%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Participants will have a current (or past) diagnosis of Intermittent Explosive Disorder (IED) or have a Life History of Aggression (LHA) score equal or greater than 12. In addition, all participants must meet the following criteria:
Exclusion Criteria:
All subjects with the following are excluded from study:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
One single dose of pimavanserin (34 mg oral)
Drug: Pimavanserin 34 mg
One single dose of matching placebo
Drug: Placebo
5HT-2a receptor antagonist
Also known as: Nuplazid
Inactive Comparator
Aggressive Responding on the Taylor Aggression Paradigm (TAP)
In the TAP, the subject competes against a fictitious opponent in a reaction time game during which the investigator manipulates provocation by having the "opponent" select increasing (mild) electric shock levels (i.e., a physically aggressive threat) which then elicits aggressive responding to the "confederate" when he/she loses a reaction-time task. Subjects can select shock from level 1 to level 9, and to select a "high" (10 level) or a "very high" (20 level) shock. The total number of "High" / "Very High" (10/20) shocks selected for the opponent is the outcome for heightened aggression in this study.
Time frame: The TAP will be done about five (5) hours after administration of pimavanserin and after placebo.
Social-Emotional Information Processing (Video-SEIP)
The V-SEIP contains eight video stories presenting possible (i.e., socially ambiguous) aggressive encounters between "Actor A" (who the subject is told to identify with) and "Actor B" who physically, or verbally, assaults the "primary individual". After viewing each video story (\~ 10 seconds), the subject is asked to record all the elements of the video they recall; this is referred to as encoding (ENC). Then, the subject rates the likelihood that "Actor B" acted towards "Actor A" because he/she wanted to physically/emotionally hurt the other person (Hostile Attribution: HA). Finally, the subject is asked to rate the likelihood of how angry/upset they would be if this "event" happened to them (Negative Emotional Response: NER).
Time frame: The V-SEIP will be done about five (5) hours after administration of pimavanserin and after placebo.
Plan to share: No
Started Aug 2024 (actual). Primary completion is estimated for Jan 2027, 29 months after the start.
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Studies of the drug tested here: Pimavanserin
Disruptive, Impulse Control, and Conduct Disorders →