Studies with psychedelic drugs in human volunteers

Scientific curiosity and fascination have played a key role in human research with psychedelics along with the hope that perceptual alterations and heightened insight could benefit well-being and play a role in the treatment of various neuropsychiatric disorders. These motivations need to be tempered by a realistic assessment of the hurdles to be cleared for therapeutic use. Development of a psychedelic drug for treatment of a serious psychiatric disorder presents substantial although not insurmountable challenges. While the varied psychedelic agents described in this chapter share some properties, they have a range of pharmacologic effects that are reflected in the gradation in intensity of hallucinogenic effects from the classical agents to DMT, MDMA, ketamine, dextromethorphan and new drugs with activity in the serotonergic system. The common link seems to be serotonergic effects modulated by NMDA and other neurotransmitter effects. The range of hallucinogens suggest that they are distinct pharmacologic agents and will not be equally safe or effective in therapeutic targets. Newly synthesized specific and selective agents modeled on the legacy agents may be worth considering. Defining therapeutic targets that represent unmet medical need, addressing market and commercial issues, and finding treatment settings to safely test and use such drugs make the human testing of psychedelics not only interesting but also very challenging. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Abuse liability measures for use in analgesic clinical trials in patients with pain: IMMPACT recommendations

Assessing and mitigating the abuse liability (AL) of analgesics is an urgent clinical and societal problem. Analgesics have traditionally been assessed in randomized clinical trials (RCTs) designed to demonstrate analgesic efficacy relative to placebo or an active comparator. In these trials, rigorous, prospectively designed assessment for AL is generally not performed. The Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) convened a consensus meeting to review the available evidence and discuss methods for improving the assessment of the AL of analgesics in clinical trials in patients with pain. Recommendations for improved assessment include: (1) performing trials that include individuals with diverse risks of abuse; (2) improving the assessment of AL in clinical trials (eg, training study personnel in the principles of abuse and addiction behaviors, designing the trial to assess AL outcomes as primary or secondary outcome measures depending on the trial objectives); (3) performing standardized assessment of outcomes, including targeted observations by study personnel and using structured adverse events query forms that ask all subjects specifically for certain symptoms (such as euphoria and craving); and (4) collecting detailed information about events of potential concern (eg, unexpected urine drug testing results, loss of study medication, and dropping out of the trial). The authors also propose a research agenda for improving the assessment of AL in future trials.

Core outcome measures for opioid abuse liability laboratory assessment studies in humans: IMMPACT recommendations

A critical component in development of opioid analgesics is assessment of their abuse liability (AL). Standardization of approaches and measures used in assessing AL have the potential to facilitate comparisons across studies, research laboratories, and drugs. The goal of this report is to provide consensus recommendations regarding core outcome measures for assessing the abuse potential of opioid medications in humans in a controlled laboratory setting. Although many of the recommended measures are appropriate for assessing the AL of medications from other drug classes, the focus here is on opioid medications because they present unique risks from both physiological (e.g., respiratory depression, physical dependence) and public health (e.g., individuals in pain) perspectives. A brief historical perspective on AL testing is provided, and those measures that can be considered primary and secondary outcomes and possible additional outcomes in AL assessment are then discussed. These outcome measures include the following: subjective effects (some of which comprise the primary outcome measures, including drug liking; physiological responses; drug self-administration behavior; and cognitive and psychomotor performance. Before presenting recommendations for standardized approaches and measures to be used in AL assessments, the appropriateness of using these measures in clinical trials with patients in pain is discussed.

Research design considerations for clinical studies of abuse-deterrent opioid analgesics: IMMPACT recommendations

Opioids are essential to the management of pain in many patients, but they also are associated with potential risks for abuse, overdose, and diversion. A number of efforts have been devoted to the development of abuse-deterrent formulations of opioids to reduce these risks. This article summarizes a consensus meeting that was organized to propose recommendations for the types of clinical studies that can be used to assess the abuse deterrence of different opioid formulations. Because of the many types of individuals who may be exposed to opioids, an opioid formulation will need to be studied in several populations using various study designs to determine its abuse-deterrent capabilities. It is recommended that the research conducted to evaluate abuse deterrence should include studies assessing: (1) abuse liability, (2) the likelihood that opioid abusers will find methods to circumvent the deterrent properties of the formulation, (3) measures of misuse and abuse in randomized clinical trials involving pain patients with both low risk and high risk of abuse, and (4) postmarketing epidemiological studies.

Risk management of drug products and the U.S. Food and Drug Administration: evolution and context

This paper summarizes the background and origins of pharmaceutical risk management and minimization principles and approaches as reflected in FDA statute, policy, and practice. It describes the history of early "risk management" programs, such as the patient package inserts (PPIs) introduced for oral contraceptives in 1976 and medication guides developed for products with safety concerns over the past decade. Exemplary products and programs that include restricted distribution systems such as the early clozapine "blood for drug" program are discussed. The principles and tools described in the US Food and Drug Administration (FDA) risk management guidances of 2005 are likely to be relied upon as the REMS (Risk Evaluation and Mitigation Strategies) mandated by the FDA Amendments Act (FDAAA) of 2007 are implemented.

Cocaine Rapid Efficacy Screening Trial (CREST): a paradigm for the controlled evaluation of candidate medications for cocaine dependence

AIM

Development of effective medications for the treatment of cocaine dependence remains a major priority for the National Institute on Drug Abuse (NIDA) at the National Institutes of Health. The Cocaine Rapid Efficacy Screening Trial (CREST) paradigm was developed by the Division of Treatment Research and Development (DT R&D) at NIDA with the goal of enhancing pilot clinical trial validity when systematically assessing a range of medications and drug classes for potential utility in treatment of cocaine dependence.

DESIGN

CREST utilizes a randomized, controlled, parallel group, blinded methodology for comparing one or more marketed medications against a standard, pharmaceutical grade placebo. The trial design is comprised of a flexible 24-week screening/baseline period followed by randomization to an 8-week treatment period.

MEASURES

Standard measures of outcomes for the CREST included urinary benzoylecgonine (primary metabolite of cocaine), retention, cocaine craving, depression, clinical global impression and HIV-risk behaviors. In order to facilitate comparisons of data from the CREST studies across sites, drug classes and time, standardized procedures, measures and psychosocial counseling were used.

RESULTS

A total of 19 medications were evaluated in out-patient treatment research clinics in Boston, Cincinnati, Los Angeles, New York and Philadelphia.

CONCLUSIONS

Findings supported decisions to move forward three medications (cabergoline, reserpine, tiagabine) using full-scale, adequately powered, randomized placebo-controlled trial designs. Lessons learned from the CREST experience continue to shape cocaine pharmacotherapy trial design and execution.

A placebo-controlled screening trial of tiagabine, sertraline and donepezil as cocaine dependence treatments

AIMS

To conduct a preliminary evaluation of the safety and efficacy of tiagabine, sertraline or donepezil versus an unmatched placebo control as a treatment for cocaine dependence.

DESIGN

A 10-week out-patient study was conducted using the Cocaine Rapid Efficacy and Safety Trial (CREST) study design.

SETTING

This study was conducted at the Cincinnati Medication Development Research Unit (MDRU) and at an affiliated site in Dayton, Ohio.

PARTICIPANTS

Participants met Diagnostic and Statistical Manual version IV (DSM-IV) criteria for cocaine dependence. Sixty-seven participants were enrolled with 55 completing final study measures.

INTERVENTION

The targeted daily doses of medication were tiagabine 20 mg, sertraline 100 mg and donepezil 10 mg. All participants received 1 hour of manualized individual cognitive behavioral therapy on a weekly basis.

MEASUREMENTS

Primary outcome measures of efficacy included urine benzoylecgonine (BE) level, Cocaine Clinical Global Impression Scale-Observer and self-report of cocaine use. Safety measures included adverse events, ECGs, vital signs and laboratory tests.

FINDINGS

Subjective measures of cocaine dependence indicated significant improvement for all study groups. Generalized estimating equations analysis indicated that the tiagabine group showed a trend toward a significant decrease in urine BE level from baseline to weeks 5-8 (P = 0.10) and non-significant changes for the other study groups. No pattern of physical or laboratory abnormalities attributable to treatment with any of the medications was identified. There were three serious adverse events reported, none of which were related to study procedures.

CONCLUSIONS

The present findings suggest that tiagabine may be worthy of further study as a cocaine dependence treatment.

Efficacy screening trials of paroxetine, pentoxifylline, riluzole, pramipexole and venlafaxine in cocaine dependence

AIMS

The two studies presented here were conducted to assess the efficacy of paroxetine, pentoxifylline, riluzole, venlafaxine and pramipexole as medications for the treatment of cocaine dependence.

DESIGN

A multi-arm, modified blinded, placebo-controlled design was used.

SETTING

The studies were conducted at the Boston VA Healthcare System and the Boston University School of Medicine Medication Development Research Unit (MDRU).

PARTICIPANTS

Participants met criteria for cocaine dependence during a 2-week screening period.

INTERVENTION

Following random assignment to one of the treatment groups, subjects received active medication or placebo for 8 weeks in combination with cognitive behavioral counseling. In the first study the efficacy of the antidepressant paroxetine (20 mg daily), the phosphodiesterase inhibitor pentoxifylline (1200 mg daily) and the glutamate release inhibitor riluzole (100 mg daily) was assessed. The antidepressant venlafaxine (150 mg daily) and the dopamine agonist pramipexole (1.5 mg daily) were evaluated in the second study.

MEASUREMENTS

Urine benzoylecgonine (BE) concentrations, self-report of cocaine use and global impression scores served as primary outcome measures. Secondary measures included assessments of cocaine craving and psychiatric functioning. Adverse events were monitored during the treatment period.

FINDINGS

None of the active medications produced greater reductions in urine BE concentrations over the treatment period than did placebo. There were trends for BE levels to become reduced in the pentoxifylline group during the first 4 weeks of treatment and for Addiction Severity Index (ASI) drug composite scores to be lower in the pentoxyfylline group at end-point compared to the placebo group. Significant within-group reductions in reported cocaine use and craving were found for all treatment groups, but none of the active medications were superior to placebo on these measures. The accuracy of self-reported cocaine use declined over the study period. Overall, the active medications were well tolerated.

CONCLUSIONS

This study does not support the use of paroxetine, pentoxifylline, riluzole, venlafaxine or pramipexole for the treatment of cocaine dependence. However, these results need to be interpreted with caution because of the small size and lack of homogeneity of the experimental groups.

A medication screening trial evaluation of reserpine, gabapentin and lamotrigine pharmacotherapy of cocaine dependence

AIMS

To conduct a preliminary evaluation of the safety and efficacy of reserpine, gabapentin or lamotrigine versus an unmatched placebo control as a treatment for cocaine dependence.

DESIGN

A 10-week out-patient study using the Cocaine Rapid Efficacy and Safety Trial (CREST) study design.

SETTING

The study was conducted at the Cincinnati Medication Development Research Unit (MDRU).

PARTICIPANTS

Participants met Diagnostic and Statistical Manual version IV (DSM-IV) criteria for cocaine dependence. Sixty participants were enrolled, with 50 participants completing the final study measures.

INTERVENTION

The targeted daily doses of medication were reserpine 0.5 mg, gabapentin 1800 mg and lamotrigine 150 mg. All participants received 1 hour of manualized individual cognitive behavioral therapy on a weekly basis.

MEASUREMENTS

Primary outcome measures of efficacy included urine benzoylecgonine (BE) level, Cocaine Clinical Global Impression scale--observer and self-report of cocaine use. Safety measures included adverse events, electrocardiograms (ECGs), vital signs and laboratory tests.

FINDINGS

Subjective measures of cocaine dependence indicated significant improvement for all study groups. Urine BE results indicated a significant improvement for the reserpine group (P < 0.05) and non-significant changes for the other study groups. No pattern of physical or laboratory abnormalities attributable to treatment with any of the medications was identified. There were three serious adverse events reported, none of which were related to study procedures. The medications appeared to be tolerated well.

CONCLUSIONS

The present findings suggest that reserpine may be worthy of further study as a cocaine dependence treatment.

Safety and health policy considerations related to the use of buprenorphine/naloxone as an office-based treatment for opiate dependence

Opiate dependence remains a fundamental challenge confronting health delivery systems and is often characterized as a social and moral issue. The impact of this disorder on healthcare policy is changing with the increased incidence of HIV, hepatitis C, and tuberculosis infections in opiate-dependent patients. These medical illnesses have substantial effect on escalating healthcare costs, and, therefore, also affect healthcare policy priorities, which are responsive to these costs. Pharmacological treatments for opiate dependence have had limited success; often the consequence of limited access to care. Hence, there is a need to develop new pharmacotherapies for opiate dependence that extend the range of clinical options, including new first-line treatment approaches. This paper will focus on the safety and health policy considerations related to the use of buprenorphine and buprenorphine/naloxone based on data derived from clinical trials and post-marketing surveillance that provide evidence for the use of the medications as first-line treatments in an office-based environment. The evaluation of this evidence formed the basis by the National Institute on Drug Abuse to support and pursue the evaluation and registration of buprenorphine/naloxone and buprenorphine in a public/private sector cooperative effort to become an office-based, first-line treatment for opiate dependence.

Plans, designs, and analyses for clinical trials of anti-cocaine medications: where we are today. NIDA/VA/SU Working Group on Design and Analysis

Increased interest in addiction psychopharmacology has raised unique methodologic issues in the design, conduct, and analysis of outcomes in clinical trials of therapeutic agents for drug dependence. This article summarizes issues raised at a meeting in Palo Alto, California, on November 4, 1996, that was sponsored by the Medication Development Division of the National Institute on Drug Abuse and the Department of Veterans Affairs Cooperative Studies Program to discuss the methodologic issues in clinical trials of cocaine pharmacotherapy.

Gabapentin monotherapy: I. An 8-day, double-blind, dose-controlled, multicenter study in hospitalized patients with refractory complex partial or secondarily generalized seizures. The US Gabapentin Study Group 88/89

We evaluated the efficacy and safety of gabapentin administered as monotherapy in an 8-day, randomized, double-blind, dose-controlled, parallel-group, multicenter study comparing dosages of 300 and 3,600 mg/d gabapentin in 82 hospitalized patients whose antiepileptic medications had been discontinued for seizure monitoring. Seizures under study were complex partial seizures with or without secondary generalization. Patients exited the study if they experienced a protocol-defined exit event indicating lack of efficacy. Time to exit was significantly longer (p = 0.0001) and completion rate was significantly higher (53% versus 17%; p = 0.002) for patients receiving 3,600 mg/d gabapentin. Gabapentin was well tolerated by patients in both dosage groups, and no patients exited the study due to adverse events, despite rapid initiation of full dose within 24 hours. These results demonstrate that gabapentin has anticonvulsant activity and is well tolerated when administered as monotherapy in patients with refractory partial seizures.

Gabapentin in generalized seizures

The efficacy of gabapentin (Neurontin), in generalized seizures was evaluated in this 14 week, double-blind, placebo-controlled, parallel-group, add-on, multicenter study. A total of 129 patients with refractory generalized seizures were randomized to receive either placebo or 1200 mg/day gabapentin as add-on therapy. Patients received their standard regimens of antiepileptic drugs (AEDs) during a 12 week baseline period, and gabapentin or placebo was added-on in the subsequent 14 week evaluation period. Results of both an intent-to-treat (ITT) and evaluable-patient analyses showed that gabapentin provided greater reduction in the frequency of generalized tonic-clonic seizures than did placebo; however, the differences between treatments were not statistically significant. Gabapentin did not affect the frequency of absence or myoclonic seizures. Adverse events were reported by 67% of gabapentin-treated patients and by 56% of placebo-treated patients. The most frequently occurring adverse events among patients receiving gabapentin were somnolence, fatigue, and dizziness. Gabapentin is well tolerated by patients with generalized seizures. The results of this study show a trend toward an effect of gabapentin in reducing the frequency of generalized tonic-clonic seizures and suggest that further exploration of high dose gabapentin in generalized epilepsy is warranted.

Gabapentin as add-on therapy for refractory partial epilepsy: results of five placebo-controlled trials

Gabapentin (GBP, Neurontin), a new antiepileptic drug (AED) with a novel mechanism of action, exhibits low acute toxicity in mice, rats, and monkeys, and is not teratogenic. GBP pharmacokinetics are simple and predictable; GBP is eliminated by urinary excretion, is not protein-bound or metabolized, does not induce or inhibit hepatic enzymes, and does not interact with other AEDs. In five placebo-controlled, double-blind studies of GBP as add-on therapy, 307 patients with refractory partial seizures received placebo and 485 received GBP dosages of 600, 900, 1,200, or 1,800 mg/day for 12 weeks following a 12-week baseline. Seizure frequency, as measured by response ratio and responder rate, was improved for patients receiving GBP compared with placebo; differences were statistically significant in two of the three large, multicenter studies. Adverse events occurred in 76% of GBP-treated patients, compared with 57% of placebo-treated patients. No serious adverse events were consistently attributable to GBP therapy. Changes in clinical laboratory values were not considered clinically important. GBP represents a significant addition to the armamentarium of AEDs available for treatment of patients with epilepsy.

The dynamics of metabolic change following seizures as measured by positron emission tomography with fludeoxyglucose F 18

OBJECTIVE

To examine the time course of alterations in glucose metabolism in relation to the interval from the last seizure, focus laterality, seizure frequency, and seizure type.

DESIGN

Metabolic study with the use of positron emission tomography with fludeoxyglucose F 18. Blinded scan evaluation with use of a standard template. Multivariate regression analysis of positron emission tomographic data.

SETTING

National Institutes of Health Clinical Center, Bethesda, Md.

PATIENTS

Thirty-two adults with intractable partial epilepsy and lateralized seizure onset documented by video-electroencephalographic monitoring.

MAIN OUTCOME MEASURE

Normalized metabolic rate for glucose ipsilateral and contralateral to the epileptic focus.

RESULTS

The most dramatic changes occurred in inferior temporal regions; the midtemporal region was affected as well. Effects lasting 48 hours were found after both simple and complex partial seizures. The time course was different for the two types of seizures. The inferior temporal metabolic rate ipsilateral to the focus increased compared with the interictal rate during the 24-hour period following simple partial seizures; a nadir occurred in the second 24 hours. The rate then rose to an intermediate level after 48 hours. The relative to an intermediate level after 48 hours. The relative regional increase in ipsilateral metabolism following complex partial seizures persisted for 48 hours before falling.

CONCLUSION

The brain may take longer than 24 hours after a partial seizure to return to its baseline state.

Temporal lobectomy for uncontrolled seizures: the role of positron emission tomography

We evaluated the role of positron emission tomography (PET) with [18F]deoxyglucose (FDG) (FDG-PET) for planning surgery in 53 patients who had temporal lobectomy for uncontrolled seizures at National Institutes of Health from 1981 to 1990. Investigators blinded to PET data used results of telemetered video-electroencephalographic ictal monitoring and other standard criteria to decide whether subdural electrodes (22 patients, i.e., the "invasive" group) should be implanted or surgery performed. PET scans were analyzed using a standard regional template. Mean lateral but not mesial temporal asymmetry was significantly higher in patients who became seizure free (p < 0.03). Patients with > or = 15% hypometabolism were significantly more likely to be seizure free in the entire study population and the invasive subgroup. Visual identification of hypometabolism was less accurate. When a clear temporal ictal surface electroencephalographic focus was present, FDG-PET provided less additional information. FDG-PET may be particularly valuable if the surface electroencephalographic scan is nonlocalizing. In addition to helping to identify the seizure focus, it may allow limitation of invasive electrode placement to those necessary for functional mapping. When PET is used to identify epileptic foci, quantitative measurements of asymmetry should be made.

Comparison of PET measurements of cerebral blood flow and glucose metabolism for the localization of human epileptic foci

We compared the relative sensitivity of two interictal PET techniques, bolus injection of [15O] labeled water for estimation of cerebral blood flow (H2(15)O CBF-PET), and 18F 2-deoxyglucose (18FDG-PET) for cerebral glucose metabolism (CMRglc), and T2-weighted magnetic resonance imaging, in 28 patients with medically intractable complex partial seizures undergoing evaluation for surgery. There were statistically significant associations between lateralization by 18FDG-PET, and MRI, but not H2(15)O CBF-PET, and lateralization of the epileptic focus as defined by scalp-sphenoidal ictal EEG. Fifteen patients had surgery or subdural electrodes. 18FDG-PET was more closely associated with a good outcome than H2(15)O CBF-PET, which, in addition, showed hypoperfusion contralateral to the epileptic temporal lobe in several cases. H2(15)O sensitivity may have been reduced by technical factors, but 18FDG-PET appears to be more specific for localization of epileptic zones.

PET imaging of opiate receptor binding in human epilepsy using [18F]cyclofoxy

We used [18F]cyclofoxy (CF), a potent opiate antagonist with affinity for mu and kappa receptors, and the Scanditronix PC1024-7B PET scanner to study 14 patients with complex partial seizures (CPS), and 14 normal controls. Epileptic foci were localized by prolonged EEG-video monitoring. EEG was recorded continuously during each scan. Immediately before CF administration, [15O]labeled water was used to measure cerebral blood flow, and showed hypoperfusion ipsilateral to the EEG focus. Blood samples (corrected for radiolabeled metabolites) and tissue time-activity data were acquired over 90 min following bolus CF injection. Anatomic regions were outlined directly on the PET images. A kinetic model was used to derive the total volume of distribution (Vt) in each brain region. Specific binding (Vs) was determined by substracting non-specific binding (Vt) measured in a receptor-poor brain region (occipital cortex). Regions with high Vs included mesial temporal lobes, thalamus, basal ganglia, and frontal cortex. Individual patients appeared to have higher binding in temporal lobe ipsilateral to the EEG focus, but there was no asymmetry for the patients as a group in mean Vt or Vs in anterior mesial, posterior mesial, anterior lateral, posterior lateral temporal cortex, thalamus, basal ganglia, or, for Vt, in regions of low specific binding: occipital lobe, parietal lobe, cerebellum.

Cerebral metabolism and depression in patients with complex partial seizures

Twenty-three patients with complex partial seizures were evaluated with 18F-2-deoxyglucose positron emission tomography and with the Beck Depression Inventory. Five of 10 patients with left and zero of eight with right temporal electroencephalographic foci had depressive symptoms; one of five patients with poorly localized electroencephalographic foci also scored in the depressed range. Temporal, frontal, caudate, and thalamic normalized glucose metabolic rates among five patients with depressive symptoms and well-localized left temporal epileptogenic regions were compared with five patients without depressive symptoms but with similar electroencephalographic characteristics. Multifactorial analysis of variance yielded a significant nonlateralized mood by region interaction. Of nine individual regions compared, only inferior frontal cortex showed a significant difference in normalized regional metabolic rate between depressed and nondepressed patients. Metabolism in this region also distinguished patients with depressive symptoms from normal control subjects. Depressive symptoms in patients with complex partial seizures are associated with a bilateral reduction in inferior frontal glucose metabolism, compared with patients without depressive symptoms and normal control subjects. The frontal lobe hypometabolism observed in patients with depressions associated with epilepsy, Parkinson's disease, and primary affective disorder suggests that similar frontal lobe metabolic disturbances could underlie these conditions.

Cerebral activation during speech discrimination in temporal lobe epilepsy

Eight patients with uncontrolled complex partial seizures underwent positron emission tomography with 18-fluoro-2-deoxyglucose both at rest and during an auditory order discrimination task using speech syllables. Eight age-matched controls were scanned under identical conditions; an additional 18 normal subjects were scanned only at rest. No consistent task-related changes were seen in control subjects. For the 3 patients with left temporal epileptogenic foci, left inferior temporal lobe hypometabolism was more evident during the activated than during the resting scan. Activation procedures may augment the diagnostic yield of metabolic scanning in epilepsy.

Effect of valproate on human cerebral glucose metabolism

We studied the effects of valproate (VPA) on local cerebral glucose metabolism (LCMRglc) in eight patients with partial seizure disorders and two with primary generalized epilepsy. Each patient had two positron-emission tomography (PET) scans with 18F-2-deoxyglucose (FDG), with, and without, VPA (mean level 52 mg/dl, range 30-127 mg/dl). Patients continued carbamazepine (CBZ) for both scans: serum concentrations were not significantly changed by VPA (CBZ range 5.4-12 mg/dl). Seven patients had the "without-VPA" scan first. Mean interval between PET scans was 75 days. Global CMRglc was decreased by 22% by addition of VPA (7.2 +/- 1.8 mg/100 g/min without VPA, 5.6 +/- 1.1 g/min with VPA, p less than 0.05, corrected). Thirteen regions of interest (ROIs) were analyzed in each hemisphere in each PET scan. Metabolic rates were significantly lower in 15 of 26 ROIs with VPA (p less than 0.05, corrected). VPA depresses cerebral metabolism to a greater degree than do CBZ and phenytoin (PHT) but less than does phenobarbital (PB). The metabolic effect may be related to the mechanism of action and have neuropsychological implications.

Congenital mirror movements. Abnormal organization of motor pathways in two patients

We studied 2 patients with congenital mirror movements by means of various neurophysiological and metabolic techniques, including mapping of motor evoked potentials to transcranial electrical and magnetic stimulation, premovement and somatosensory evoked potentials, kinematics of voluntary movements, muscle reflexes, and positron emission tomography (PET). Abnormalities in maps of motor and premovement potentials and in PET scans were consistent with a bilateral representation of hand muscles in the motor cortex, the existence of physiologically active connections capable of conducting fast efferent volleys from the motor cortex to ipsilateral muscles, the presence of mirror EMG activity in either hand with intended voluntary movement of the other hand, the absence of mirrored EMG responses from wrist flexors and extensors to mechanical perturbation of the contralateral wrist, and normal scalp distribution of somatosensory evoked potentials to right and left median nerve stimulation. Our findings are consistent with aberrant organization of motor representation areas and corticospinal pathways with ipsilateral as well as contralateral control of voluntary movement.

Neuroendocrinology and limbic epilepsy: relationships to psychopathology, seizure variables, and neuropsychological function

Correlations were sought among neuroendocrine, psychopathologic, neuropsychological, and seizure variables in 16 male patients with limbic epilepsy. Plasma prolactin and luteinizing hormone levels were directly correlated with seizure frequency. Plasma prolactin was inversely correlated with thought disorder. Post hoc findings included a strong direct correlation between total plasma testosterone levels and aggression. These relationships may help to elucidate mechanisms related to interictal symptomatology in patients with limbic epilepsy.

Psychopathology and limbic epilepsy: relationship to seizure variables and neuropsychological function

Correlations were sought among psychopathologic, neuropsychological, and seizure variables in 21 patients with limbic epilepsy. Observer-based assessments, such as the Bear-Fedio Inventory, and self-report assessments of psychopathology were used. Self-reported psychotic experiences were associated with increased seizure frequency. Increased religiosity was noted in patients whose epileptic focus included the left side. Increased neuropsychological impairment was associated with several measures of psychopathology, including those related to thought disorder, psychoticism, and affective disturbance.

Sporadic Creutzfeldt-Jakob disease in two coworkers

We report the coincidence of pathologically confirmed sporadic CJD in two unrelated schoolteachers who shared a school wing for 9 months. The first developed ataxia, tremulousness, and dementia 5 months after his last contact with his colleague. Diagnosis of CJD was made 2 months later by brain biopsy. Eight months later, the second teacher developed similar symptoms and died after 9 months. Whether this unique coincidence reflects mere chance or some form of direct viral transmission is unknown. Continued epidemiologic surveillance for any future "coincidence" is warranted.