Placebo-controlled study of gabapentin treatment of panic disorder.

A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate the efficacy and safety of gabapentin in relieving the symptoms of panic disorder. One hundred three patients were randomly assigned to receive double-blind treatment with either gabapentin (dosed flexibly between 600 and 3,600 mg/day) or placebo for 8 weeks. No overall drug/placebo difference was observed in scores on the Panic and Agoraphobia Scale (PAS) (p = 0.606). A post hoc analysis was used to evaluate the more severely ill patients as defined by the primary outcome measure (PAS score > or = 20). In this population, the gabapentin-treated patients showed significant improvement in the PAS change score (p = 0.04). In patients with a PAS score of 20 or greater, women showed a greater response than men regardless of treatment. Adverse events were consistent with the known side effect profile of gabapentin and included somnolence, headache, and dizziness. One patient experienced a serious adverse event during the study. No deaths were reported. The results of this study suggest that gabapentin may have anxiolytic effects in more severely ill patients with panic disorder.

Gabapentin in bipolar disorder: a placebo-controlled trial of adjunctive therapy. Gabapentin Bipolar Disorder Study Group.

OBJECTIVES: [corrected] To assess efficacy and safety of gabapentin in the treatment of bipolar disorder. METHODS: This was a double-blind, placebo-controlled trial of adjunctive gabapentin (dosed flexibly between 900 and 3,600 mg/day). Patients with a lifetime diagnosis of bipolar disorder (type I), and who were currently suffering from symptoms of either mania, hypomania or a mixed state despite ongoing therapy with lithium, valproate, or lithium and valproate in combination were eligible for inclusion. The primary efficacy measures were the baseline to endpoint change in total score on the Young Mania Rating Scale (YMRS) and the Hamilton Depression Rating Scale (HAM-D). RESULTS: Both treatment groups had a decrease in total YMRS from baseline to endpoint, but this decrease was significantly greater in the placebo group (-9) than the gabapentin group (-6) (p < 0.05). No difference between treatments was found for the total score on the HAM-D. Secondary efficacy measures were not different between treatment groups. More patients in the placebo group had changes made to their ongoing lithium therapy (n = 12) compared to the gabapentin group (n = 4). When these patients are removed from the efficacy analysis, the YMRS treatment difference still favors placebo, but is no longer statistically significant. Based on gabapentin plasma levels at termination, some patients did not take the study drug as prescribed. CONCLUSIONS: The findings of this study did not demonstrate that gabapentin is an effective adjunctive treatment when administered to outpatients with bipolar disorder.

Placebo-controlled trial of the CCK-B antagonist, CI-988, in panic disorder.

BACKGROUND: Based on the induction of panic-like symptoms by infusion of cholecystokinin (CCK) peptide in normals and panic disorder patients, it has been proposed that CCK may play a role in the disease mechanisms underlying anxiety disorders. Selective antagonists of CCK-B receptors can block the challenge-induced symptoms in a dose-dependent manner, leading to the hypothesis that these compounds may have anxiolytic effects. METHODS: A randomized, double-blind study was carried out to compare the effects of placebo with CI-988, a selective antagonist of the CCK-B receptors. Following a one-week placebo lead-in, patients with Panic Disorder with or without Agoraphobia received either placebo or CI-988 100 mg TID for six weeks. Panic attacks were recorded by a daily diary method. RESULTS: A total sample of 88 patients was planned but and interim analysis was carried out when about half the patients had been enrolled (n = 41). All patients improved during treatment and no difference in the weekly rate of panic attacks was seen between the treatment groups. The study was terminated at this point due to the remote likelihood of showing a treatment difference. CONCLUSIONS: CI-988 was not superior to placebo in reducing panic attacks. Several explanations are possible, including the poor pharmacokinetic characteristics of CI-988 which may make it unsuitable to test the CCK hypothesis of anxiety.

Treatment of social phobia with gabapentin: a placebo-controlled study.

A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate the efficacy and safety of gabapentin in relieving the symptoms of social phobia. Sixty-nine patients were randomly assigned to receive double-blind treatment with either gabapentin (dosed flexibly between 900 and 3,600 mg daily in three divided doses) or placebo for 14 weeks. A significant reduction (p < 0.05) in the symptoms of social phobia was observed among patients on gabapentin compared with those on placebo as evaluated by clinician- and patient-rated scales. Results were similar for the intent-to-treat and week-2 completer populations. Adverse events were consistent with the known side effect profile of gabapentin. Dizziness (p = 0.05), dry mouth (p = 0.05), somnolence, nausea, flatulence, and decreased libido occurred at a higher frequency among patients receiving gabapentin than among those receiving placebo. No serious adverse events or deaths were reported. On the basis of these limited data, it seems that gabapentin offers a favorable risk-benefit ratio for the treatment of patients with social phobia. Further studies are required to confirm this effect and to determine whether a dose-response relationship exists.

Effects of the CCK(B) antagonist CI-988 on responses to mCPP in generalized anxiety disorder.

In order to evaluate the effect of the CCK(B) antagonist CI-988 on behavioral, neuroendocrine, and physiologic responses to the mixed, post-synaptic serotonin (5-HT) agonist/antagonist mCPP, 16 patients with a principal DSM-III-R diagnosis of generalized anxiety disorder (GAD) were enrolled in a study that involved two challenge tests. On one day, patients received a single oral dose of CI-988 followed 30 min later by an i.v. infusion of 0.1 mg/kg mCPP. On a second test day patients received placebo CI-988 followed 30 min later by active i.v. mCPP. The sequence of CI-988 was randomly assigned and the testing was conducted in double-blind fashion. In an initial dose-finding phase (N = 6) with a dose of CI-988 of 25 mg, there were no significant between-test differences in behavioral response to mCPP. Accordingly, the second phase of the study was conducted with a CI-988 dose of 100 mg in another of patients (N = 10). CI-988 (100 mg) was well tolerated and had no significant effects on pretest anticipatory anxiety. There was no significant blunting of the anxiety response to mCPP as a result of CI-988 administration, nor did CI-988 affect physiologic or neuroendocrine measures. Correlations between peak changes in plasma levels of CI-988 and mCPP-induced anxiety in the high-dose patient group were not significant. Overall, these findings did not provide evidence of anxiolytic effects of CI-988 in patients with GAD. The lack of effect of CI-988 on neuroendocrine and physiological measures further suggests that CI-988's pharmacological effects could be independent of 5-HT function. However, follow-up studies using higher doses of CI-988 are indicated to confirm this preliminary finding as are studies more closely evaluating the interrelationship between CCK and 5-HT function in GAD.

Two year follow-up of atypical depression.

The symptom cluster of Atypical Depression (AD) has been characterized based on its presentation and selective response to pharmcological treatments, while relatively little is known about the outcome of these patients after treatment trials. The present study was undertaken to assess the long term outcome of 40 patients after a controlled treatment trial of fluoxetine vs phenelzine. Twenty five of these subjects were interviewed approximately two years after completion of the initial trial. They reported a high frequency of symptom recurrence, but generally little symptomatic or social impairment between episodes. Eighteen subjects were taking antidepressants at follow-up. A higher frequency of depressive episodes was recorded during the times when off antidepressant medications. Overall outcome was rated as moderate or good in the majority of subjects. These results suggest that AD presents from similarities with other subtypes of depression, with high rates of symptomatic recurrence and lasting response to chronic antidepressant treatment. Conversely, social functioning and overall outcome appear more favorable in AD.

Sleep-onset rapid eye movement after electroconvulsive therapy is more frequent in patients who respond less well to electroconvulsive therapy.

The response to electroconvulsive therapy (ECT) was monitored with sleep polysomnography studies (SPS) performed pre- and post-ECT, in 25 patients with major depressive disorder (MDD). Patients included in this study met research diagnostic criteria for MDD and had been free of psychotropic medication for at least 10 days before SPS were performed. We compared ECT responders and nonresponders on SPS, demographic, and clinical parameters. Many SPS parameters, regardless of the clinical response, changed significantly with ECT. The presence of delusions was significantly associated with SOREM post-ECT. The presence of sleep-onset REM periods post-ECT was associated with poor response to ECT. SPS performed during a course of ECT may help identify patients at risk of responding less well to this modality of treatment.

The cholecystokinin-B receptor antagonist CI-988 failed to affect CCK-4 induced symptoms in panic disorder patients.

The effects of the cholecystokinin-B (CCK-B) receptor antagonist CI-988 on symptoms elicited by the cholecystokinin tetrapeptide (CCK4) were studied in DSM-IIIR patients with panic disorder. The study employed a double-blind, two-period incomplete block design. Patients (n = 14) received two different dosages of CI-988 (50 mg or 100 mg) or placebo 2 h prior to an IV bolus injection of CCK4 (20 micrograms) on two separate occasions. The primary efficacy parameter was the total intensity score on the Panic Symptoms Scale (PSS). Secondary parameters were the number of panic symptoms, time to and occurrence of the first panic symptoms, duration of symptoms, intensity of apprehension and the percentage of patients who did not have a panic attack. The PSS failed to show a statistically significant treatment effect on any of these outcome measures. The average panic rate was 50%, 14.3% and 37.5% after placebo, 50 and 100 mg CI-988, respectively. The differences in panic rate were not statistically significant. The results of this study suggest that CI-988 in doses up to 100 mg is not effective in reducing symptoms of panic anxiety induced by CCK4.

Polysomnographic studies in patients referred for ECT: pre-ECT studies.

Forty-one patients referred for electroconvulsive therapy (ECT) were evaluated with a standardized clinical protocol and had polysomnographic studies performed pre-ECT after 10 or more days drug free. Clinical evaluations were performed by blind investigators and included the Research Diagnostic Criteria and the Hamilton Rating Scale for Depression (HRSD). Patients were categorized according to the clinical response. Thirty patients (73%) reached a post-ECT HRSD < or = 10, whereas 21 of them (51.2%) reached a post-ECT HRSD score < or = 6. Sleep-onset rapid eye movement (SOREM) periods were present in 27 (66%) of the patients. Few polysomnographic variables differentiated between excellent responders and patients with residual symptoms. Older patients had significantly more disrupted polysomnographic study parameters. Although present in a significant proportion of patients, baseline SOREM was not a factor in outcome.

Fluoxetine versus phenelzine in atypical depression.

A study was conducted to compare the relative efficacy of fluoxetine and phenelzine in patients with mood-reactive atypical depression. Forty-two patients with atypical depression by the Columbia criteria were studied in a randomized, double-blind treatment study. Following a single-blind placebo lead-in, patients received fluoxetine 20-60 mg/day or phenelzine 45-90 mg/day for 6 weeks. Efficacy was measured by the Hamilton Depression Rating Scale, the Clinical Global Impression (Severity and Improvement) scales, and the Patient Global Impression (Improvement) scale. Of 42 patients randomized, 2 patients never received drugs and 2 phenelzine-treated patients dropped out prior to completion; the remainder completed the 6 weeks of the study. The rates of treatment response did not differ between groups. With a few exceptions (e.g., tremor), phenelzine produced more frequent adverse effects than fluoxetine. It was concluded that fluoxetine is as effective as phenelzine in the treatment of atypical depression, but produces fewer adverse effects and is better tolerated.

Analgesic efficacy of enadoline versus placebo or morphine in postsurgical pain.

Enadoline, a selective agonist of the kappa-opioid receptor, was studied for its analgesic efficacy in patients with pain after obstetric or gynecologic surgery. An initial study involving a comparison of enadoline (2, 5, 15 micrograms), an acetaminophen-codeine (ACET/COD) combination, and placebo showed all treatments to be ineffective analgesics. Therefore, a second study with the same design but using higher doses of enadoline (15 and 25 micrograms) and replacing ACET/COD with morphine 10 mg i.m. was conducted. Enadoline 25 micrograms produced similar pain relief to that of morphine, although of shorter duration, and better than enadoline 15 micrograms or placebo. However, enadoline was associated with dose-limiting neuropsychiatric adverse events, which led to early termination of the study.

Effect of gabapentin (Neurontin) [corrected] on mood and well-being in patients with epilepsy.

1. Global improvement data from five double-blind clinical trials of gabapentin as add-on therapy in patients with epilepsy were reviewed to assess the effects of gabapentin on mood. 2. One hundred and ninety-four (46%) of 423 gabapentin-treated patients reported improvements in general well-being as compared with 79 (29%) of the 271 placebo-treated patients. 3. Findings support anecdotal reports of improved affective status among patients taking gabapentin and suggest that the study of gabapentin in psychiatric populations may be warranted.

Analgesic efficacy of the kappa-receptor agonist, enadoline, in dental surgery pain.

To study the analgesic efficacy of enadoline, a selective agonist of the kappa-opioid receptor, a double-blind, randomized comparison was made of enadoline versus placebo and a combination of acetaminophen-codeine in patients with pain after surgical extraction of impacted molar teeth. An initial study involving a comparison of enadoline, a combination, and placebo failed to show any analgesic effect of enadoline. Therefore, a second study with the same design but using higher doses of enadoline was conducted. Despite continued safety and tolerability even at the higher doses, enadoline could not be shown to be superior to placebo. The acetaminophen-codeine combination was significantly more effective than enadoline or placebo. Enadoline did not show analgesic efficacy in this study. Possible reasons for this lack of efficacy are discussed.

A double-blind, placebo-controlled study of a CCK-B receptor antagonist, CI-988, in patients with generalized anxiety disorder.

This multicenter, double-blind, placebo-controlled, parallel-group, randomized study assessed the efficacy, safety, and tolerability of a novel CCK-B antagonist CI-988 in the treatment of generalized anxiety disorder (GAD). Patients received placebo or CI-988 (300 mg/day, thrice daily) for 4 weeks. Patients with a primary diagnosis of GAD according to DSM-III-R criteria were randomized. The study design included a 1- to 2-week single-blind placebo baseline phase, followed by a 4-week double-blind treatment phase. Efficacy was measured weekly by Hamilton Rating Scale for Anxiety (HAM-A), Clinical Global Impressions of Severity and Change, UCLA-Multi Dimensional Anxiety Scale, and Hamilton Rating Scale for Depression. Patients were also evaluated to determine whether they met criteria for irritable bowel syndrome (IBS) at screening and were evaluated with a gastrointestinal visual analog scale at each visit. Eighty-eight patients were randomized to CI-988 (N = 45) and placebo (N = 43) at three centers. CI-988 did not demonstrate an anxiolytic effect superior to placebo in this clinical trial. There was no significant difference in mean change in HAM-A total between placebo (-7.73) and CI-988 (-8.64). However, a significant treatment-by-center interaction and a highly variable placebo response rate among the three centers limit the interpretation of the results. CI-988 did not have an effect on symptoms of IBS other than diarrhea, which worsened in patients with IBS. Other than a higher incidence of some gastrointestinal symptoms (diarrhea, dyspepsia, flatulence, and nausea), CI-988 was well tolerated. Results suggest that testing higher oral doses of CI-988 may be warranted.

Shortened REM latency PostECT is associated with rapid recurrence of depressive symptomatology.

Electroconvulsive therapy (ECT) is highly effective in the treatment of major depressive disorder (MDD). The 1-year relapse rates are reported to be high and in the 30%-60% range, however. To test whether polysomnography (PS) can identify patients with a propensity for relapse we studied 20 patients, responders to a course of ECT, with PS studies. All patients met baseline diagnostic criteria for MDD, were treated with ECT following standardized protocols, had PS studies performed after the course of ECT in a medication-free state, received maintenance antidepressants postECT, and were followed periodically with phone interviews. The recurrence of depressive symptoms was determined at 3 months and 6 months after discharge. Fifty-five percent of the patients were symptomatic when evaluated 6 months after the ECT. Sleep Onset rapid eye movement (REM) periods were identified in 55% of the patients. As a group, patients who had experienced a recurrence of depressive symptoms by 6 months after discharge, had significantly shorter REM latencies after the course of ECT. A shorter REM latency after ECT identified patients who at six months demonstrated significant depressive symptomatology. Shortened REM latency after ECT in patients with MDD appears to be a correlate of vulnerability for relapse.

Latency to rapid eye movement sleep as a predictor of treatment response to fluoxetine and placebo in nonpsychotic depressed outpatients.

Fluoxetine and placebo were compared in 89 outpatients with major depression with (n = 45) or without (n = 44) a reduced or shortened rapid eye movement latency (SREML) (< or = 65 minutes) to determine whether rapid eye movement latency (REML) predicted placebo and/or antidepressant response. Men and women were stratified based on polysomnographic recordings and then randomly assigned to receive double-blind fluoxetine (20 mg/day) or placebo for 8 weeks after a 2-week, single-blind, placebo lead-in period. Fluoxetine-treated patients demonstrated a significantly greater reduction in the Hamilton Rating Scale for Depression total score and a significantly greater response rate than placebo-treated patients in both the SREML and the combined strata. Treatment differences in the non-SREML stratum were not statistically significant. Results supported REML as a predictor of placebo nonresponse but did not predict a differential fluoxetine response in patients with SREML compared with patients without SREML.

Clinical characteristics of patients with concurrent major depressive disorder and panic disorder.

OBJECTIVE: This study was designed to test the hypothesis that patients with both major depressive disorder and panic disorder exhibit more clinical symptoms and have a more protracted course of illness than patients with major depressive disorder only. METHOD: The authors compared standardized clinical evaluations (from Schedule for Affective Disorders and Schizophrenia interviews) of 119 patients with major depressive disorder only and 57 patients with major depressive disorder and concurrent panic disorder. Clinical and demographic variables were included. RESULTS: The patients with both disorders reported symptoms of major depressive disorder earlier in life and also required treatment and hospital admission earlier in life. Many clinical features during the index episode were significantly more severe in the patients with both disorders. A logistic regression identified a "panic index" consisting of the symptoms of somatic anxiety, phobia, indecisiveness, and feelings of inadequacy. Scores on this index allowed proper classification of patients to either of the two diagnostic groups with high reliability. CONCLUSIONS: In major depressive disorder, the presence of panic disorder is suggestive of a more severe and precocious form of illness.

Seasonal symptom variation in patients with chronic fatigue: comparison with major mood disorders.

The psychobiology of idiopathic fatigue has received renewed interest in the medical literature in recent years. In order to examine the relation between chronic, idiopathic fatigue and specific subtypes of depressive illness, we characterized the pattern and severity of seasonal symptom variation in 73 patients with chronic, idiopathic fatigue, compared to patients with major depression (n = 55), atypical depression (n = 35), and seasonal affective disorder (n = 16) Fifty of the fatigued subjects also met the specific Centers for Disease Control and Prevention case criteria for chronic fatigue syndrome, though this definition was unable to discriminate a distinct subgroup of patients, based on their seasonality scores alone. As a group, the fatigued subjects reported the lowest levels of symptom seasonality of any of the study groups. Further, even in those fatigued subjects with scores in the range of those seen in patients with seasonal affective disorder, seasonality was not reported to be a subjectively distressing problem. These findings lend support to the idea that although chronic fatigue shares some clinical features with certain mood disorders, they are not the same illnesses. These data are also consistent with the emerging view that chronic fatigue represents a heterogeneously determined clinical condition.

Sleep Electroencephalographic Studies After ECT.

Forty-one patients with major depressive disorder were treated with electroconvulsive therapy (ECT). Sleep polysomnography studies (SPSs) were performed after the course of ECT. The hypotheses tested were that age is a significant factor in post-ECT SPS results and that some SPS parameters are correlates of outcome of ECT. An interaction between age and response to ECT could not be identified; however, older patients demon strated significantly disrupted sleep post-ECT. Response to ECT was associated with lower REM activity and lower REM density. Sleep-onset REM periods post-ECT were observed in almost 50% of the patients regardless of age. The SPS monitoring of recovery after a course of ECT may identify sleep correlates of response to ECT and variables associated with poorer longitudinal outcome.