The Effect of Imipramine on Early Information Processing

Study Overview
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Brief Summary
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We wanted to compare the relation of two different psychophysiological paradigms (PrePulse Inhibition of the startle response = PPI and P50 suppression) to each other. Additionally, we wanted to test the effect of the combined serotonin- and noradrenaline re-uptake inhibitor, imipramine, on these measures. The primary hypothesis was that PPI and P50 gating would not correlate with each other at baseline. The secondary hypothesis was that increased noradrenergic and serotonergic activity would disrupt PPI as well as P50 gating.

Detailed Description
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Schizophrenic patients exhibit impairments in filtering of sensory information, as can be assessed by use of prepulse inhibition (PPI) of the acoustic startle response and P50 suppression paradigms. In the treatment of negative symptoms or depressive syndromes during the course of schizophrenia antidepressants are often combined with antipsychotic medication. However, antidepressants increase monoaminergic activity, of which in turn it has been suggested to decrease sensory gating, although these presumptions are mostly based on results from animal studies. Currently, little is known about monoaminergic modulation of sensory filtering in humans, and the few reports that can be found in literature show discrepancies with animal studies. The current study was designed to study the effects of increased monoaminergic activity on sensory filtering and habituation of healthy volunteers. In a double-blind, placebo controlled cross-over design, twenty healthy male volunteers will receive either placebo or a dose of 50 mg of imipramine (a dual acting antidepressant), after which they will be tested in a P50 suppression-, a PPI-, and a habituation of the startle reflex paradigm.

Official Title
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Early Information Processing in Healthy Controls: Studies on the Relation Between Two Different Paradigms (PPI and P50ERP) and Effects of Pharmacological Interventions

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Drug: imipramine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male subjects Good Physical and Mental Health meeting criteria never mentally ill, which will be evaluated with a medical history checklist, ECG Non smokers Exclusion Criteria: Current use of any medication Any subject who has received any investigational medication within 30 days prior to the start of this study History of neurologic illness History of psychiatric illness in first-degree relatives, evaluated with DSM-IV criteria History of alcohol and drug abuse. Positive urine screening for amphetamine, cocaine, cannabis, or ecstasy.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br> | Drug: imipramine<br>* Either 50 mg of imipramine or placebo will be administered to healthy male volunteers<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory gating |  | Once, 1 hour after administration of capsule | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PPI of the startle reflex |  | once, one hour after administration | 
| P50 suppression |  | once, one hour after administration | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Psychophysiology, PPI, P50 suppression, Imipramine