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Biomedical subjects

R B Lydiard

Publications and source records attributed to R B Lydiard.

At least 109 records · Page 6Linked to original sources
PubMed1992

A fixed-dose study of alprazolam 2 mg, alprazolam 6 mg, and placebo in panic disorder.

A recently reported multinational, 8-week double-blind, placebo-controlled study assessing the efficacy of alprazolam versus placebo in the treatment of panic disorder indicated significant differences favoring alprazolam. We now report the results of a three-site, 6-week, double-blind, fixed-dose study comparing alprazolam 2 mg, alprazolam 6 mg, and placebo in 94 patients with panic disorder with or without agoraphobia. Both alprazolam treatment groups (6 mg and 2 mg) improved significantly more than did the placebo treatment group on most outcome measures. Only a few statistically significant differences between the 6 mg and 2 mg alprazolam groups were discerned, although the pattern of treatment response across measures suggested a dose effect. Dropouts in the placebo group were primarily due to lack of efficacy and in the alprazolam 6 mg group were due to side effects, which may have contributed to the limited differences between groups at study end. The findings suggest that many patients may require less than 6 mg of alprazolam per day for effective treatment of panic disorder.

Adolescent↗
PubMed1992

Oral contraceptives and panic disorder.

BACKGROUND: There are no published reports of an association between triphasic oral contraceptives and the development of panic disorder. METHOD: The authors describe two cases in which the use of triphasic oral contraceptives in women appear to have precipitated panic disorder. Treatment with the triphasic oral contraceptives was stopped and the patients were followed for 2 years. RESULTS: Both subjects had rapid and total resolution of their panic disorder symptoms following cessation of triphasic oral contraceptive medications. CONCLUSION: Triphasic oral contraceptives in some predisposed women may lead to precipitation of panic disorder.

Adult↗
PubMed1992

The effects of pregnancy on preexisting panic disorder.

BACKGROUND: Limited evidence suggests that pregnancy may be associated with a reduction of panic and related symptoms. The authors investigate reported changes in panic symptoms during pregnancy. METHOD: Questionnaires asking about changes in panic and phobic avoidance symptoms during pregnancy were mailed to 129 women who had previously participated in our Anxiety Disorders Program over a 5-year period; all had diagnoses of panic disorder by DSM-III-R criteria. Reported here are responses from 22 of the women who experienced pregnancy after the onset of panic disorder. RESULTS: A majority of women (14 of 22) reported a decrease in panic symptoms during pregnancy, but significant variability in this phenomenon occurs between and within individuals. CONCLUSION: A subpopulation of women may experience improvement in panic symptoms during pregnancy, which has implications for management of these patients. Further research is needed to verify the existence of such a subpopulation and to determine an etiology.

Agoraphobia↗
PubMed1991

Dopamine blocking activity of clomipramine in patients with obsessive-compulsive disorder.

While many data suggest that Obsessive-Compulsive Disorder (OCD) is an illness accompanied by dysregulation of the serotonergic system, interesting clinical evidence and animal studies also suggest possible dysregulation of the dopaminergic (DA) system. In order to determine whether clomipramine (CMI), an antiobsessional agent, is capable of altering DA function, we performed a neuroleptic radioreceptor assay (NRRA) on plasma samples from OCD patients before and after treatment in a double-blind, placebo controlled trial of CMI. CMI produced mild but significant DA D-2 receptor binding activity in an in vitro assay. The degree of dopamine binding activity did not correlate with clinical response to clomipramine. Because it has been suggested that another drug with antiobsessional efficacy, fluoxetine, may also have dopamine blocking properties, it may be speculated that antidopaminergic activity in combination with serotonergic effects is involved in antiobsessional activity of effective agents for some patients.

Adolescent↗
PubMed1991

Brain MRI in obsessive-compulsive disorder.

Magnetic resonance imaging (MRI) brain scans were performed on 12 patients with obsessive-compulsive disorder and 12 healthy controls. Measurements of the area of the head of the caudate nucleus, cingulate gyrus thickness, intracaudate/frontal horn ratio, and area of the corpus callosum did not differ between the two groups. These limited data do not support the presence of a consistent gross brain structural abnormality in obsessive-compulsive disorder. Further studies using other anatomic measurements and other brain structural imaging techniques are warranted.

Adult↗
PubMed1991

Speed of onset of action of the newer antidepressants--fluoxetine and bupropion.

The authors review 24 double-blind placebo-controlled studies comparing fluoxetine or bupropion against previously available antidepressants, to assess where there is evidence for a difference in the speed of onset of antidepressant action. Critical comparison of the studies showed no difference in speed of onset of action between these newer agents and conventional antidepressants.

Antidepressive Agents↗
PubMed1991

Substance abuse in an inpatient psychiatric sample.

The relationship between psychoactive drug abuse and psychopathology is complex. There have been few systematic explorations of substance abuse in psychiatric populations since the recent epidemic of cocaine abuse. To update and further explore the relationship between psychiatric illness and substance abuse, 100 consecutively admitted patients to an inpatient psychiatry unit were administered a drug and alcohol use/abuse questionnaire. Sixty-four percent endorsed current or past problems with substance abuse and 29% met DSM-III-R criteria for substance abuse in the 30 days prior to admission. For the major diagnostic categories, there were no significant differences between groups in percentages of patients with substance abuse disorders. There was a trend (p less than or equal to .2) toward an increased number of lifetime psychiatric hospitalizations in the substance-abusing group. Alcohol was the most common drug of choice followed by stimulants, cannabis, and sedative hypnotics. Differences in drug choices between diagnostic categories are discussed. Forty-three percent of urine drug screens obtained were positive, and of those with positive urine drug screens, 42% denied drug use upon admission. Only 40% of patients with current or past substance abuse problems had received treatment for their chemical dependency. In our sample, while substance abuse was very prevalent, it was underreported and undertreated.

Adult↗
PubMed1991

Pharmacokinetics, pharmacodynamics, and treatment issues of benzodiazepines: alprazolam, adinazolam, and clonazepam.

Alprazolam, adinazolam, and clonazepam share the typical pharmacological effects of benzodiazepines yet are diverse in their pharmacokinetic properties. Alprazolam has an average terminal elimination half-life of 12 hours, whereas adinazolam generates a metabolite responsible for its benzodiazepine effects whose half-life is less than 3 hours. Clonazepam shows a much slower elimination with a half-life of 20 to 80 hours. The rate of decline of plasma benzodiazepine concentration may be an important factor in determining the number of daily doses necessary to maintain optimal anti-panic effects and to minimize rebound anxiety and withdrawal effects. Clonazepam, which has a longer half-life, would be expected to have some advantages over the other drugs. The limited data available do not provide evidence for any substantial advantages of one benzodiazepine over another. The potential disadvantage of the rapid elimination half-life of adinazolam and its metabolite may be offset by formulation in a sustained release capsule. When discontinuing therapy abruptly, a benzodiazepine with a longer half-life may be advantageous; however, when pharmacotherapy is discontinued gradually, the importance of half-life is diminished. Studies of the pharmacodynamics of drug-receptor interactions suggest new approaches to minimizing the adverse effects of discontinuing benzodiazepine therapy. Preliminary data relating plasma alprazolam concentrations to anxiolytic and adverse effects are presented.

Alprazolam↗
PubMed1991

Cocaine-induced psychosis.

BACKGROUND: Chronic stimulant use can produce a paranoid psychosis that is similar to acute paranoid schizophrenia. While this phenomenon has been systematically explored in amphetamine abusers, it has been relatively unexplored in a systematic fashion in cocaine abusers. METHOD: The experience of cocaine-induced psychosis was evaluated in 55 individuals consecutively admitted for treatment of DSM-III-R cocaine dependence. Each subject was interviewed about their experiences of psychosis while intoxicated by means of a standardized, semistructured interview. RESULTS: Fifty-three percent (29/55) of those interviewed reported experiencing transient cocaine-induced psychosis. There was no significant difference in lifetime amount of cocaine use or amount of cocaine use in the month before admission between those who experienced psychosis and those who did not. The psychosis-positive group used significantly more cocaine in the year prior to admission (p less than or equal to .02) and had a longer duration of use (p less than or equal to .01). Males were significantly (p less than or equal to .05) more likely than females to develop psychosis. Ninety percent (26/29) developed paranoid delusions directly related to drug use. Ninety-six percent (28/29) of the subjects experienced hallucinations: 83% (24/29), auditory hallucinations; 38% (11/29), visual hallucinations; and 21% (6/29), tactile hallucinations. Twenty-seven percent (15/55) of subjects developed transient behavioral stereotypies. CONCLUSION: Cocaine-induced paranoia is a common experience among chronic users. Amount and duration of use are related to its development. Implications for a kindling model of cocaine-induced psychosis will be discussed.

Administration, Inhalation↗