A double-blind comparison of Org 3770, amitriptyline, and placebo in major depression

BACKGROUND

A 6-week, double-blind, dose titration study was performed to evaluate efficacy and safety of the new antidepressant Org 3770 in comparison with amitriptyline and placebo.

METHOD

One hundred fifty outpatients of both sexes, 18 years and older, with a DSM-III diagnosis of major depressive episode, were randomly assigned to 6 weeks of treatment with Org 3770, amitriptyline, or placebo.

RESULTS

At baseline, mean 17-item Hamilton Rating Scale for Depression (HAM-D) scores of all treatment groups were higher than 25, thus indicating that a large proportion of severely depressed patients entered the study. The overall mean daily doses were 22 mg/day for Org 3770, 133 mg/day for amitriptyline, and 4.9 capsules/day for placebo. The majority of times assessments were made, both active drugs produced significantly greater improvements than placebo on all efficacy variables (17-item HAM-D, Montgomery-Asberg Depression Rating Scale, Clinical Global Impressions, and Zung Self-Rating Depression Scale). After 6 weeks of treatment, significantly greater (p < or = .05) proportions of patients in both active treatment groups (70% in the Org 3770- and 58% in the amitriptyline-treatment groups) than in the placebo-treatment group (33%) were HAM-D responders. Org 3770 was well tolerated in this study; dry mouth and somnolence were the only adverse experiences that occurred significantly more frequently with Org 3770- than with placebo-treated patients. By contrast, treatment with amitriptyline was related to significantly higher rates of dry mouth, constipation, and dyspepsia as compared with both Org 3770 and placebo, and significantly higher rates of somnolence as compared with placebo.

CONCLUSION

In this study, Org 3770 was as effective as amitriptyline in the treatment of major depression, with advantages regarding improvements of depressed mood (HAM-D Item 1), responder rates, and safety.

Functional neuroanatomical correlates of the effects of stress on memory

Recently there has been an increase in interest in the relationship between stress and memory. Brain regions which are involved in memory function also effect the stress response. Traumatic stress results in changes in these brain regions; alterations in these brain regions in turn may mediate symptoms of posttraumatic stress disorder (PTSD). Neural mechanisms which are relevant to the effects of stress on memory, such as fear conditioning, stress sensitization, and extinction, are reviewed in relation to their implications for PTSD. Special topics including neural mechanisms in dissociation, neurobiological approaches to the validity of childhood memories as they apply to controversies over the "False Memory Syndrome," and implications of the effects of stress on memory for psychotherapy, are also reviewed. The findings discussed in this paper are consistent with the formulation that stress-induced alterations in brain regions and systems involved in memory may underlie many of the symptoms of PTSD, as well as dissociative amnesia, seen in survivors of traumatic stress.

Effects of the benzodiazepine antagonist flumazenil in PTSD

OBJECTIVE

Evidence from preclinical and clinical studies suggests a role for alterations in the benzodiazepine/GABAA receptor complex in stress and anxiety. Flumazenil is a relatively pure benzodiazepine/GABAA antagonist with limited intrinsic activity. In panic disorder patients, but not healthy controls, flumazenil has been demonstrated to provoke panic attacks.

METHOD

Vietnam combat veterans with PTSD (n = 14) received 90-second intravenous infusions of flumazenil 2 mg or placebo in a double-blind, crossover study design. PTSD symptomology was assessed using the PTSD Symptom Scale, and anxiety symptoms were measured with visual analogue rating scales.

RESULTS

There was no significant difference in PTSD and anxiety symptoms between administration of flumazenil and placebo.

CONCLUSION

Flumazenil administration does not produce an increase in anxiety and PTSD symptoms in patients with PTSD. This suggests that PTSD and panic disorder are dissimilar in terms of benzodiazepine/GABAA system function.

Synthesis and PET imaging of the benzodiazepine receptor tracer [N-methyl-11C]iomazenil

The central benzodiazepine receptor tracer [N-methyl-11C]iomazenil (Ro 16-0154) was synthesized by alkylation of the desmethyl precursor noriomazenil with [11C]methyl iodide. The [11C]CH3I (prepared by reduction of [11C]CO2 with LiA1H4 followed by reaction with HI) was reacted with noriomazenil in N,N-dimethylformamide and Bu4N+OH- for 1 min at 80 degrees C and purified by HPLC (C18, 34% CH3CN/H2O 7 mL/min). The product was obtained with synthesis time 35 +/- 5 min (mean +/- SD, n = 7), radiochemical yield (EOB) 36 +/- 16%, radiochemical purity 99 +/- 1%, and specific activity 5100 +/- 2800 mCi/mumol. Absorbed radiation doses were calculated from previously acquired human biodistribution data. The urinary bladder wall received the highest dose (0.099 mGy/MBq) for 4.8 h voiding interval and the effective dose equivalent was 0.015 mSv/MBq. After i.v. injection of [11C]iomazenil in an adult baboon or healthy human volunteer, radioactivity accumulated in the cortex with time-activity curves in agreement with results obtained with [11C]flumazenil PET and [123I]iomazenil SPECT studies. The count rate was sufficient to obtain quantitative images up to 2 h post-injection with a 14 mCi injection. These results suggest that [11C]iomazenil will be a useful agent for measuring benzodiazepine receptors in vivo by positron emission tomography.

MRI-based measurement of hippocampal volume in patients with combat-related posttraumatic stress disorder

OBJECTIVE

Studies in nonhuman primates suggest that high levels of cortisol associated with stress have neurotoxic effects on the hippocampus, a brain structure involved in memory. The authors previously showed that patients with combat-related posttraumatic stress disorder (PTSD) had deficits in short-term memory. The purpose of this study was to compare the hippocampal volume of patients with PTSD to that of subjects without psychiatric disorder.

METHOD

Magnetic resonance imaging was used to measure the volume of the hippocampus in 26 Vietnam combat veterans with PTSD and 22 comparison subjects selected to be similar to the patients in age, sex, race, years of education, socioeconomic status, body size, and years of alcohol abuse.

RESULTS

The PTSD patients had a statistically significant 8% smaller right hippocampal volume relative to that of the comparison subjects, but there was no difference in the volume of other brain regions (caudate and temporal lobe). Deficits in short-term verbal memory as measured with the Wechsler Memory Scale were associated with smaller right hippocampal volume in the PTSD patients only.

CONCLUSIONS

These findings are consistent with a smaller right hippocampal volume in PTSD that is associated with functional deficits in verbal memory.

Subanesthetic effects of the noncompetitive NMDA antagonist, ketamine, in humans. Psychotomimetic, perceptual, cognitive, and neuroendocrine responses

BACKGROUND

To characterize further behavioral, cognitive, neuroendocrine, and physiological effects of subanesthetic doses of ketamine hydrochloride in healthy human subjects. Ketamine, a phencyclidine hydrochloride derivative, is a dissociative anesthetic and a noncompetitive antagonist of the N-methyl-D-aspartate subtype of excitatory amino acid receptor.

METHODS

Nineteen healthy subjects recruited by advertisements from the community participated in this randomized, double-blind, placebo-controlled study. Subjects completed three test days involving the 40-minute intravenous administration of placebo, ketamine hydrochloride (0.1 mg/kg), or ketamine hydrochloride (0.5 mg/kg). Behaviors associated with the positive and negative symptoms of schizophrenia were assessed by using the Brief Psychiatric Rating Scale. Changes in perception and behaviors associated with dissociative states were assessed by the Perceptual Aberration Subscale of the Wisconsin Psychosis Proneness Scale and the Clinician-Administered Dissociative States Scale. Cognitive function was assessed by using the (1) Mini-Mental State Examination; (2) tests sensitive to frontal cortical dysfunction, including a continuous performance vigilance task, a verbal fluency task, and the Wisconsin Card Sorting Test; and (3) tests of immediate and delayed recall. Plasma levels of cortisol, prolactin, homovanillic acid, and 3-methoxy-4-hydroxyphenethyleneglycol were measured.

RESULTS

Ketamine (1) produced behaviors similar to the positive and negative symptoms of schizophrenia; (2) elicited alterations in perception; (3) impaired performance on tests of vigilance, verbal fluency, and the Wisconsin Card Sorting Test; (4) evoked symptoms similar to dissociative states; and (5) preferentially disrupted delayed word recall, sparing immediate recall and postdistraction recall. Ketamine had no significant effect on the Mini-Mental State Examination at the doses studied. Ketamine also had no effect on plasma 3-methoxy-4-hydroxyphenethyleneglycol levels, although it blunted a test day decline in plasma homovanillic acid levels at the higher dose. It also dose dependently increased plasma cortisol and prolactin levels. Ketamine produced small dose-dependent increases in blood pressure.

CONCLUSIONS

These data indicate that N-methyl-D-aspartate antagonists produce a broad range of symptoms, behaviors, and cognitive deficits that resemble aspects of endogenous psychoses, particularly schizophrenia and dissociative states.

SPECT measurement of benzodiazepine receptors in human brain with iodine-123-iomazenil: kinetic and equilibrium paradigms

Iodine-123-iomazenil binding to benzodiazepine receptors in human brain was measured with SPECT using kinetic and equilibrium methods.

METHODS

In the kinetic experiments (n = 6), regional time-activity curves after a single bolus injection of the tracer were fit to a three-compartment model to provide estimates of the rate constants K1 to k4. The binding potential (equal to the product of the receptor density and affinity) was derived from the rate constants. In the equilibrium method (n = 8), the tracer bolus injection was followed by a constant tracer infusion to induce a sustained equilibrium state. The regional equilibrium volume of distribution was calculated as the ratio of the regional brain concentration-to-the free parent tracer steady-state plasma concentration. In three experiments, a receptor-saturating dose of flumazenil was injected for direct measurement of the nondisplaceable compartment distribution volume.

RESULTS

The kinetic and equilibrium method results were in good agreement in all regions investigated. Iodine-125-iomazenil binding potential measured in vitro in 12 postmortem samples was found to be consistent with SPECT in vivo measurements.

CONCLUSION

These studies demonstrated the feasibility of quantification of receptor binding with SPECT.

Use of the Structured Clinical Interview for DSM-IV Dissociative Disorders for systematic assessment of dissociative symptoms in posttraumatic stress disorder

OBJECTIVE

This study compared dissociative symptom areas in Vietnam combat veterans with posttraumatic stress disorder (PTSD) and in Vietnam combat veterans without PTSD.

METHOD

The Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D) was used to compare dissociative symptoms in 40 Vietnam combat veterans with PTSD and 15 Vietnam combat veterans without PTSD. The SCID-D yields a total score and scores in five symptom areas: amnesia, depersonalization, derealization, identity confusion, and identity alteration.

RESULTS

The PTSD patients had more severe dissociative symptoms in each of the five symptom areas of the SCID-D and higher total symptom scores. Amnesia was the symptom area with the greatest difference in scores between the PTSD patients (mean = 3.68, SD = 0.73) and the non-PTSD veterans (mean = 1.06, SD = 0.26).

CONCLUSIONS

The finding of higher levels of dissociative symptoms in Vietnam combat veterans with PTSD than in Vietnam veterans without PTSD is consistent with a level of dissociative symptoms in PTSD similar to that in dissociative disorders.

Deficits in short-term memory in posttraumatic stress disorder

OBJECTIVE

The purpose of this study was to compare the memory function of patients with posttraumatic stress disorder (PTSD) to that of matched comparison subjects.

METHOD

Vietnam veterans with combat-related PTSD (N = 26) were compared to physically healthy comparison subjects (N = 15) matched for age, race, sex, years of education, handedness, socioeconomic status, and alcohol abuse. Memory and intelligence were assessed with a battery of neuropsychological tests, including the Russell revision of the Wechsler Memory Scale, the Selective Reminding Test, and subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R).

RESULTS

The PTSD patients scored significantly lower than the comparison subjects on the Wechsler Memory Scale logical memory measures for immediate recall (mean = 11.6, SD = 3.3 versus mean = 20.9, SD = 6.6) and delayed recall (mean = 8.0, SD = 3.3 versus mean = 17.8, SD = 6.4). The PTSD patients also scored significantly lower on the total recall, long-term storage, long-term retrieval, and delayed recall measures for the verbal component of the Selective Reminding Test and on the recall, long-term storage, long-term retrieval, and continuous long-term retrieval measures for the visual component of the Selective Reminding Test. There was no significant difference between the PTSD patients and comparison subjects in prorated full-scale IQ as measured by the WAIS-R.

CONCLUSIONS

Patients with PTSD may have deficits in short-term memory. Counseling and rehabilitation that address these deficits may be of value for PTSD patients.

[123I]iomazenil SPECT imaging demonstrates significant benzodiazepine receptor reserve in human and nonhuman primate brain

SPECT imaging with [123I]iomazenil was used to measure benzodiazepine (BZ) neuroreceptor occupancy of the agonist lorazepam administered at therapeutically relevant doses in humans and supratherapeutic doses in monkeys. Lorazepam at therapeutic doses (0.03 mg/kg, i.v.) administered 90 min after the bolus injection of [123I]iomazenil had no statistically significant effect (P > 0.12) on the washout rates of regional brain activities compared to that in control subjects, although human subjects demonstrated marked sedation from the lorazepam. In baboons, the effects of higher doses of lorazepam (cumulative 0.5 mg/kg) were examined in a stepwise displacement paradigm. The in vivo potency was expressed as the ED50 (or dose required to displace 50% of receptor bound activity) and was equal to 0.34 +/- 0.01 mg/kg (mean +/- SD, n = 12). Log-logit analyses of displacement data corrected for endogenous washout showed that therapeutic doses of lorazepam were associated with < 3% BZ receptor occupancy. To examine if endogenous GABA modulates potency of the BZ agonist, the ED50 of lorazepam was compared with and without concurrent administration of tiagabine, a GABA reuptake inhibitor. These experiments were designed to measure an in vivo GABA shift of agonist potency. In vivo microdialysis demonstrated that tiagabine (up to 1 mg/kg, i.v.) increased extracellular GABA levels up to 200% of baseline, but these doses had only a minimal enhancement of lorazepam's potency to displace [123I]iomazenil. This study strongly suggests that single therapeutically relevant doses of lorazepam occupy a relatively small percentage (i.e. < 3%) of BZ receptors and that BZ binding sites have a significant (i.e. > 97%) receptor reserve.

Childhood physical abuse and combat-related posttraumatic stress disorder in Vietnam veterans

OBJECTIVE

Early trauma in the form of childhood physical or sexual abuse has been associated with adult psychopathology. The purpose of this study was to compare rates of childhood abuse in Vietnam veterans with and without combat-related posttraumatic stress disorder (PTSD).

METHOD

Premilitary stressful and traumatic events including childhood abuse and other potential predisposing factors were assessed in Vietnam combat veterans who sought treatment for PTSD (N = 38) and Vietnam combat veterans without PTSD who sought treatment for medical disorders (N = 28). Stressful and traumatic events including childhood physical abuse were assessed with the Checklist of Stressful and Traumatic Events and a clinician-administered interview for the assessment of childhood abuse. Level of combat exposure was measured with the Combat Exposure Scale.

RESULTS

Vietnam veterans with PTSD had higher rates of childhood physical abuse than Vietnam veterans without PTSD (26% versus 7%). The association between childhood abuse and PTSD persisted after controlling for the difference in level of combat exposure between the two groups. Patients with PTSD also had a significantly higher rate of total traumatic events before joining the military than patients without PTSD (mean = 4.6, SD = 4.5, versus mean = 2.8, SD = 2.9).

CONCLUSIONS

These findings suggest that patients seeking treatment for combat-related PTSD have higher rates of childhood physical abuse than combat veterans without PTSD. Childhood physical abuse may be an antecedent to the development of combat-related PTSD in Vietnam combat veterans.

Dissociation and posttraumatic stress disorder in Vietnam combat veterans

OBJECTIVE

This study compared current dissociative symptoms and dissociation at the time of specific traumatic events in Vietnam combat veterans with posttraumatic stress disorder (PTSD) and Vietnam combat veterans without PTSD.

METHOD

Vietnam combat veterans who sought treatment for PTSD (N = 53) were compared to Vietnam combat veterans without PTSD (N = 32) who sought treatment for medical problems. Dissociative symptoms were evaluated with the Dissociative Experiences Scale. Dissociation at the time of a combat-related traumatic event was evaluated retrospectively with the modified Dissociative Experiences Questionnaire. The Combat Exposure Scale was used to measure level of combat exposure.

RESULTS

There was a significantly higher level of dissociative symptoms, as measured by the Dissociative Experiences Scale, in patients with PTSD (mean = 27.0, SD = 18.0) than in patients without PTSD (mean = 13.7, SD = 16.0). This difference persisted when the difference in level of combat exposure was controlled with analysis of covariance. PTSD patients also reported more dissociative symptoms at the time of combat trauma, as measured retrospectively by the Dissociative Experiences Questionnaire (mean = 11.5, SD = 1.6) than non-PTSD patients (mean = 1.8, SD = 2.1).

CONCLUSIONS

Dissociative symptoms are an important element of the long-term psychopathological response to trauma.

Fluoxetine in depressed patients: a comparison with imipramine

The clinical efficacy and safety of fluoxetine and imipramine were compared in a double-blind, 5-week, parallel study in 40 depressed outpatients. Mean scores for most depression scales improved more in patients taking fluoxetine than in those receiving imipramine (p less than .05). Nine of 16 (56%) fluoxetine patients who completed the study and 1 of 19 (5%) imipramine patients were not at all depressed at the end of the study (p less than .001). Seven fluoxetine patients and 14 imipramine patients reported one or more adverse effects during treatment; no fluoxetine patient terminated the study early for drug-related reasons. It was concluded that fluoxetine provides effective antidepressant activity with fewer and less troublesome side effects than imipramine.

Multicenter double-blind comparison of nomifensine and imipramine for efficacy and safety in depressed outpatients

Nomifensine, a tetrahydroisoquinoline antidepressant, was compared with imipramine in a 4-week multicenter double-blind study of depressed outpatients (100 on nomifensine, 56 on imipramine). Nomifensine was at least as effective as imipramine in reducing depressive symptoms at average doses of 150 mg/day. When significant differences did occur on Hamilton Depression Rating Scale scores, they favored nomifensine for improvement in cognitive symptoms and interest in work and activities. Early in treatment, nomifensine patients also showed a better relationship between clinical response and side effects. The proportions of patients experiencing at least one side effect or dropping out due to side effects were almost twice as high in the imipramine group. Dry mouth and sedating effects were 2-3 times more frequent among imipramine patients. Thus, nomifensine demonstrated clinical efficacy at least comparable with imipramine but with indications of a more favorable side effects profile.