Management of the office patient with anxiety and depression

Initial subsensitivity to anxiolytic treatments on conflict behavior in rats: parametric studies across drug classes

In conflict paradigms, benzodiazepines (BZs) often exhibit maximal anticonflict effects only after three to four BZ exposures (anxiolytic initial subsensitivity; AIS). The present experiments examined 1) whether AIS occurs with non-BZ anxiolytics and 2) whether prior exposure to non-BZs prevents the occurrence of BZ AIS. Female rats were trained to stable responding levels on a repeated-measures punished drinking paradigm. In Experiment 1, dose-response curves for the effects of the BZs chlordiazepoxide and diazepam, the barbiturates (BBs) pentobarbital and amobarbital, and the non-BZ, non-BB agent carbamazepine were determined in five groups of rats (one group/drug); dose-response curves were determined on two occasions for each drug. There was an AIS with both BZs, with the anticonflict effect being significantly greater for dose-response determination #2. There was no AIS with the BBs (robust and dose-dependent increases in punished responding on both determinations) or with carbamazepine (weak anticonflict effect on both determinations). In Experiment 2, the rats from Experiment 1 received a single-dose challenge with chlordiazepoxide (10 mg/kg). This challenge resulted in a robust anticonflict effect in subjects with a history of repeated BZ treatment; in contrast, subjects with a history of repeated BB or carbamazepine treatment exhibited smaller anticonflict responses. These data suggest that 1) the AIS does not occur with non-BZ anxiolytics and 2) the BZ AIS cannot be prevented by repeated exposure to non-BZs.

Sexual disinhibition during treatment with a benzodiazepine: a case report

We are reporting a case of a woman with a history of drug abuse, alcohol abuse, and sexual promiscuity as a teenager who later on in life had become very religious, sober and sexually abstinent. A few years later, she began having anxiety and panic attacks, typically when in physical proximity to men and sought treatment. The patient became clearly sexually disinhibited while treated with clonazepam, a high potency anti-anxiety benzodiazepine, and her "inappropriate" sexual behavior ceased when the medication was discontinued. Given her history, it is likely that the medication weakened the already fragile defenses by the removal of the "warning signals" represented by her panic attacks. The result was a more direct expression of her sexual drive in the form of strip tease dancing and sexual promiscuity. This case suggests the importance of carefully examining the history of a patient's capacity for regulating sexual drive before prescribing an anti-anxiety drug.

The history of benzodiazepine dependence: a review of animal studies

This article provides a historical review of the animal literature relating to the development of tolerance to the behavioral effects of benzodiazepines, and the incidence of biochemical and behavioral changes that result from termination of benzodiazepine treatment (spontaneous withdrawal responses). It charts the slow emergence of a pertinent animal literature and highlights conclusions that were prevalent in 1963 (at the introduction of diazepam), 1973 (at the introduction of lorazepam), 1980 and the present day. For 25 years the animal literature has lagged behind the clinical literature, but recent studies into the neurochemical mechanisms of benzodiazepine dependence and possible treatments for withdrawal responses suggest that, at last, animal experiments may be about to make a substantial contribution.

A two-compartment exploratory model to study anxiolytic/anxiogenic effects of drugs in the rat

The response of a recently described light/dark choice novelty situation to anxiolytic and non-anxiolytic agents as well as to putative anxiogenic drugs was assessed in rats. Diazepam (1.0-10.0 mg/kg, i.p.), chlordiazepoxide (2.5-10.0 mg/kg, i.p.), and pentobarbital (pentobarbitone) (7.5-15.0 mg/kg, i.p.) enhanced rats' activity in the dark and brightly lit compartments as well as crossings between the two, while imipramine (5-20 mg/kg, i.p.) had no effects. None of these drugs changed animal locomotion in activity cages. d-Amphetamine (1.5 mg/kg, i.p.) caused a significant increase in the three parameters used to measure rats' exploratory activity, but the effect was due to an increase in the general activity of the animal. No tolerance to the effects of diazepam developed after daily treatment with 5 mg/kg i.p. for 15 days. Non-sedative and non-convulsant doses of putative anxiogenic drugs such as yohimbine (2.5-5.0 mg/kg, i.p.), picrotoxin (2.0-4.0 mg/ml, i.p.) and ethyl-beta-carboline-3-carboxylate (2.5-5 mg/kg, i.p.) reduced the exploratory activity of rats in the dark compartment. The advantages and problems of using this test to identify anxiolytic and anxiogenic drugs are discussed.

Neurotransmitters, anxiety and benzodiazepines: a behavioral review

The possible involvement of serotonin, GABA and opioid peptides in anxiety and in the mechanism of action of benzodiazepine tranquilizers have recently been the subjects of intensive biochemical, neurophysiological and behavioral research. The present review examines the behavioral evidence, viewing anxiety and benzodiazepine action as far as possible separately. Four behavioral paradigms of experimental anxiety or "conflict behaviors" are described and assessed for soundness with some practical considerations. The functional significance and pharmacology of benzodiazepine receptors are discussed, and the cases for a number of putative endogenous ligands are examined. Conflict behavior is attenuated by drugs which reduce functional serotonin activity and enhanced by serotonin agonists, but there is little evidence to implicate serotonin in benzodiazepine action. GABA antagonists both intensify conflict and reduce benzodiazepine effects, but evidence of the reverse effects with GABA agonists is more equivocal. The interpretation of behavioral effects of opiate agonists and antagonists and their interactions with benzodiazepines is hindered by their actions on motivational systems other than anxiety, and evidence for an important role of opioid peptides is only suggestive. Some promising lines for future research are indicated.

Behavioural responses to diazepam of drug-naive and experienced monkeys (Macaca mulatta)

Effects of 5 mg/kg diazepam given once a week for several weeks to drug-naive and drug-experienced monkeys were studied on a spatial delayed-alternation task. In both groups response latency was increased and the number of correct responses was reduced. The effects were consistent over weeks in the experienced monkeys, but in the naive monkeys there were greater initial effects on response latency and on repeat errors, and these lessened over 2-3 weeks. Thereafter, effects resembled those observed in the experienced group. Results are discussed in terms of the possible factors involved in the development and persistence of tolerance to benzodiazepines.

Mechanisms of the initial treatment phenomenon to diazepam in the rat

The initial treatment phenomenon (ITP) to diazepam was investigated using a conditioned suppression of drinking (CSD) paradigm. Female Sprague-Dawley rats were trained to a stable baseline of punished and unpunished responses in the CSD paradigm. In Experiment 1, a control group (1) received vehicle after the CSD session on each of seven drug test days, while group 2 was treated with 3.0 mg/kg diazepam IP after each of these sessions. On drug test days 8-12, diazepam was administered to both groups before the CSD session. Drug test days were separated by 2-3 days when the animals were untreated but performed in the CSD. Prior exposure to diazepam in group 2 after sessions 1-7 conditioned the animals so that a greater release in punished behavior was seen during sessions 8-12 than in the control group (1). In Experiment 2, one group (3) of rats was administered diazepam vehicle after the CSD session for 4 drug test days and another group (4) was injected with 5.6 mg/kg diazepam after the CSD session on these same days. On the next 4 drug test days both groups received diazepam before they performed in the CSD. An ITP was observed in both the control (3) and the drug-conditioned (4) group, although the ITP was less obvious in the conditioned group. After a 28-day period of CSD exposure without vehicle or drug treatments, 5.6 mg/kg diazepam was administered to both groups before the CSD session for an additional 8 drug test days.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of cold swim stress analgesia in rats by diazepam

It was hypothesized that diazepam (DZP) would attenuate the analgesia produced by cold swim stress because of its anxiolytic and biochemical anti-stress properties. In fact, it had the opposite effect. Administered alone, neither DZP nor its vehicle affected the nociceptive thresholds of rats, as assessed by a flinch-jump test. In combination with cold swim stress, DZP elevated nociceptive thresholds significantly more than did the stressor alone. This was true whether DZP was injected before or after exposure to the stressor, or whether or not DZP administration was acute or chronic.

The anxiogenic action of Ro 15-1788 is reversed by chronic, but not by acute, treatment with chlordiazepoxide

The benzodiazepine receptor antagonist, Ro 15-1788 (10 mg/kg) is anxiogenic in the social interaction test. Acute administration of chlordiazepoxide (5 or 10 mg/kg) did not reverse the anxiogenic effects of Ro 15-1788; however, in animals pretreated with chlordiazepoxide (5 mg/kg) for 5 days prior to testing, there was a reduction in the anxiety produced by Ro 15-1788.

Tolerance to the depressant effects of diazepam in the drug discrimination paradigm

Seven groups of rats (n = 35) were run in operant drug experiments. All groups were trained on a Fixed Ratio 10 schedule to discriminate diazepam from saline. Two groups (n = 7, n = 6), after extensive drug discrimination training (doses of 2.0 and 3.0 mg/kg diazepam), were submitted to generalization experiments with various doses of the training drug. Two additional groups, (n = 6, n = 8) in the initial phase of drug discrimination, were trained on intermediate and high doses of diazepam (i.e., 5.0 and 10.0 mg/kg). The development of tolerance to the depressant effects of diazepam for these two groups was compared to the low dose sophisticated rats. Of the above-mentioned groups, two groups were given tests after a waiting period in drug discrimination training. In this test the two groups were compared to an additional group (n = 8) in its initial phases of drug discrimination training. The results show that a large number of low doses (i.e., doses below 3.0 mg/kg) is not able to induce any tolerance to the depressant effects of diazepam in this particular paradigm. Intermediate doses of diazepam (i.e., 3.0 mg/kg), administered in a large number, induced some tolerance to the depressant effects, while another intermediate dose (5.0 mg/kg) and a high dose (10.0 mg/kg) rapidly induced a significant tolerance. Once developed, the tolerance persisted for 51 days.

Fear is not critical to classically conditioned analgesia: the effects of periaqueductal gray lesions and administration of chlordiazepoxide

A high correlation between fear and analgesia classically conditioned to footshock in rats has been reported in the literature. However, it has never been directly tested whether or not fear is in fact causal to the production of conditioned analgesia. We therefore tested whether conditioned analgesia could be elicited in the absence of fear by employing two independent methods of fear suppression. First, areas of the periaqueductal gray (PAG) previously implicated in fear were selectively lesioned. Lesions of the dorsolateral PAG significantly attenuated conditioned analgesia and markedly decreased fear responses. Second, fear was attenuated via administration of chlordiazepoxide (CDP). Rats which had been conditioned while in the presence of CDP showed no reduction in conditioned pain inhibition. These results demonstrate that: (1) fear is not causal to classically conditioned analgesia and (2) the anatomical substrates for fear and conditioned analgesia are distinct but partially overlapping. The fact that fear is not a critical antecedent for classically conditioned analgesia suggests that classical conditioning techniques may be applied clinically to increase the effectiveness of some analgesic manipulations.

Behavioural pharmacology of benzodiazepines

Acute injections of benzodiazepines produce sedative effects in the rat that can be detected by decreases in spontaneous motor activity and exploration. The effects are found with low doses, are dose-related and correlate well with plasma concentrations. With repeated daily doses there is tolerance to the sedative effects within 3-5 days even with benzodiazepines with short half-lives and no active metabolites. In the rat there may be some pharmacokinetic tolerance accounting for some of the behavioural tolerance, but pharmacokinetic changes cannot explain the tolerance to low doses of chlordiazepoxide. With chronically treated rats there is no relationship between plasma benzodiazepine concentrations and sedation. There is rapid recovery from tolerance to the sedative effects and if the animals are tested undrugged there is no detectable effect 24 h after the last dose. Anxiolytic effects emerge after a few days of benzodiazepine treatment, but after 10-20 days of treatment there is tolerance to these effects in the social interaction test and in the corticosterone-stress response.

Anxiolytic actions of chlordiazepoxide determine its effects on hyponeophagia in rats

The effects of chlordiazepoxide (0, 5, 15 mg/kg) on eating latency, eating time and amount eaten of familiar and novel foods by rats were assessed. Familiarity with the test apparatus and procedure increased feeding but reduced responsivity to chlordiazepoxide (5 mg/kg). Food deprivation increased feeding and responsivity to 5 mg/kg chlordiazepoxide but attenuated some sedative effects of 15 mg/kg chlordiazepoxide. Preference for familiar food was shown only by food-deprived, test-experienced rats. The time devoted to eating novel food, but not the amount eaten, was increased by chlordiazepoxide. These findings are discussed in the context of anxiolytic and appetitive interpretations of benzodiazepine effects on hyponeophagia , with the conclusion that reduction in apparatus neophobia largely accounts for the results observed.

Multiple sites of action for anxiogenic drugs: behavioural, electrophysiological and biochemical correlations

This review describes animal models of anxiety that are able to identify an anxiogenic drug effect. Evidence is reviewed for the anxiogenic action of several drugs that act at the GABA-benzodiazepine-chloride ionophore complex in the brain. The effects of their combinations with various other drugs thought to act at the same sites are discussed. The classification of these drugs on the basis of their behavioural profiles is compared with their classification based on biochemical and electrophysiological studies.

Behavioral Effects of Brotizolam, a New Thienotriazolodiazepine Derivative

The behavioral effect of brotizolam was investigated in mice and rats, in comparison with those of diazepam, nitrazepam and estazolam. Locomotor activity of rats in an open field situation was slightly increased with smaller doses of brotizolam and estazolam and with larger doses of nitrazepam, while it was decreased with large doses of brotizolam and estazolam. The anticonflict effect of brotizolam in rats was approximately as potent as that of diazepam and was augmented following chronic administration for 10 days. In suppressing hyperemotionality and muricide of olfactory bulbectomized rats, brotizolam was more potent than diazepam, being approximately equipotent to nitrazepam and estazolam. Brotizolam, diazepam, nitrazepam and estazolam prevented both maximal electroshock and pentetrazol convulsions in mice, the effects on the latter being much more potent than those on the former. In impairing rotarod performance, brotizolam was as potent as estazolam and nitrazepam and was much more potent than diazepam in mice, but was less potent than estazolam and nitrazepam in rats. These results indicate that brotizolam possesses pharmacological properties characteristic to benzodiazepines and that the activity is more potent than that of diazepam and approximately as potent as those of nitrazepam and estazolam.

Hyponeophagia and arousal in rats: effects of diazepam, 5-methoxy-N,N-dimethyltryptamine, d-amphetamine and food deprivation

A modified hyponeophagia test is described as an animal model of anxiety. The effects of 0, 0.3, 1.0, 3.0 and 10 mg/kg diazepam, given both acutely and for 7 days pretest, were assessed in rats. Acutely, diazepam reduced hyponeophagia over the dose range 0.3-3.0 mg/kg but 10.0 mg/kg produced sedation and large variability. Chronically, the dose-response relationships were monotonic and the maximal effect was increased, suggesting that differential tolerance occurs to the sedative, but not to the anxiolytic, effects of this drug. Increased food deprivation did not mimic benzodiazepine effects on hyponeophagia, and actually prolonged eating latency in rats treated with 5-methoxy-N,N-dimethyltryptamine (2.5 mg/kg), which does not support an interpretation of diazepam effects in terms of appetitive actions. An arousal hypothesis of hyponeophagia was proposed and supported by the antagonism of the sedative effects of 10.0 mg/kg diazepam by d-amphetamine (0.5 mg/kg). Although both male and female rats were used throughout, sex differences were few in these studies.

Food preference following acute or chronic chlordiazepoxide administration: tolerance to an antineophobic action

Chlordiazepoxide (CDP) at 15 mg/kg produced two distinct actions in a food preference test, firstly a general appetite-enhancing effect, and secondly an anti-neophobic effect. Following acute injection of CDP the rats changed from eating predominantly familiar food to a novel food. This may signify an anti-neophobic effect of CDP. However, following 10 days of treatment with CDP, the anti-neophobic effect was abolished and the choice of familiar food was enhanced. This could be an indication of a more general appetite-enhancing effect. Hence some form of tolerance may develop to CDP's effects over 10 days of treatment which selectively abolishes anti-neophobic action whilst leaving the appetite effect further enhanced. There were no indications of tolerance developing to the actions of CDP in animals familiarized with all the test foods before the preference test was run. Hence the presence of food novelty may be critical to the observation of some form of selective tolerance.

The use of social interaction as a method for detecting anxiolytic activity of chlordiazepoxide-like drugs

The social interaction test in rats provides a method for detecting anxiolytic activity that does not use food or water deprivation, or electric shock, and therefore obviates difficulties of interpretation that might arise from drug-induced changes in motivation. Since social interaction is measured under more than one test condition any overall increase or decrease in social behaviour can be detected independently from the drug x test condition interaction that characterizes an anxiolytic drug. The Geller-Seifter conflict test was designed with two schedules of reinforcement for the same reasons. Any candidate test for anxiolytic action that examines drug effects under only one experimental condition is open to misinterpretation and may also prove unreliable if the critical experimental factors ( e.g. the level of food deprivation or the shock intensity) are changed. The testing procedure in the social interaction test is relatively time consuming in terms of observer-hours, but no lengthy pretraining of the animals is required. There is no way of fully automating the scoring and therefore it is important that the observers do not know the experimental group of the rats that they are scoring, and that tape recordings are made so that the scores can be checked. It has not so far been fruitful to analyze drug effects on every individual social behaviour, but this method does allow changes in individual behaviours to be detected. By entering the data directly into a computer we are now able to store the frequency and duration of each behaviour as well as the sequence of behaviours. It will then be possible to determine whether a detailed analysis of drug effects on the patterning of social behaviours will prove a useful addition to the social interaction test

Kinetics and neuropsychologic effects of IV diazepam in the presence and absence of its active N-desmethyl metabolite in humans

In 12 healthy volunteers the kinetics and neuropsychological actions of IV diazepam (DZ) (single dose) were studied with and without the presence of its main metabolite N-desmethyldiazepam (NDDZ). Both the maximal plasma concentration and the steepness of the alpha-slope were correlated with variations in the corresponding continuous reaction time (CRT). EEG profiles, CRT and clinical ratings for anxiety and sedation all showed significant changes between the situations with the metabolite present or absent, but no significant correlation could be found with the kinetic pattern of DZ in the two situations. Tolerance to NDDZ did not develop. The results indicate that the presence of the active metabolite changes the pharmacodynamic profile of the parent compound probably by an interaction at the receptor site between DZ and NDDZ. Changes in the spectrum of effects during long-term therapy with DZ may, therefore, partly be explained in this way.

Chlordiazepoxide antinociception: cross-tolerance with opiates and with stress

Chlordiazepoxide (CDP) has been previously shown to possess antinociceptive properties that are resistant, except at high doses, to the opiate antagonist naloxone. The present study evaluated whether CDP's antinociceptive effects were subject to tolerance following repeated injections and whether cross-tolerance might develop between the antinociceptive action of CDP and that of either morphine or cold water swins. CDP increased flinch-jump thresholds following acute administration and exhibited tolerance following repeated injections. Neither morphine-tolerant nor cold water swim-adapted rats displayed an antinociceptive effect when tested with CDP. On the other hand, chronic pretreatment with CDP attenuated the antinociceptive effects of cold water swims, but did not produce any clear effect upon morphine analgesia.

A test of anxiety that distinguishes between the actions of benzodiazepines and those of other minor tranquilisers and of stimulants

The effects of minor tranquilisers and of stimulant drugs were studied in the Social Interaction test of anxiety in which the illuminance and unfamiliarity of the test arena are manipulated. Acute administration of sodium phenobarbitone (25 mg/kg) was without effect. Acute administration of sodium phenobarbitone (35 mg/kg) and of meprobamate (60 mg/kg) produced sedation: both locomotor activity and social interaction were reduced. On the other hand, amphetamine sulphate (2 mg/kg) and caffeine citrate (20 mg/kg) reduced social interaction, but increased locomotor activity. Chronic administration dissociated the pattern of results produced by sodium phenobarbitone (35 mg/kg) from that produced by flurazepam (0.5 mg/kg). With chronic treatment (5 days) neither drug reduced motor activity, but whereas phenobarbitone increased social interaction regardless of the test illuminance and unfamiliarity, the increase produced by flurazepam was limited to the more stressful test conditions, i.e., when the arena was unfamiliar or brightly lit.

Lack of tolerance development to benzodiazepines in antagonism of the pentylenetetrazol discriminative stimulus

In an operant procedure of lever pressing on FR 10 schedule of food reinforcement male hooded rats were trained to respond on a lever on one side of a food cup following a 20 mg/kg pentylenetetrazol (PTZ) injection and to respond on a lever on the alternate side following a 1 ml/kg saline injection. Upon acquisition of the PTZ-saline discrimination, diazepam and chlordiazepoxide were tested and found to antagonize the PTZ discriminative stimulus. The animals were then injected with 10 mg/kg diazepam or chlordiazepoxide for ten consecutive days. New dose-response curves obtained following this treatment indicated that tolerance did not develop to the antagonism of the PTZ discriminative stimulus by these benzodiazepines.

Can social interaction be used to measure anxiety?

1 Pairs of male rats were placed in a test box for 10 min and the time they spent in active social interaction was scored. Maximum active interaction was found when the rats were tested under low light in a box with which they were familiar. When the light level was increased or when the box was unfamiliar active social interaction decreased. 2 Exploration (time spent sniffing objects) decreased in the same way in relation to test conditions as did social interaction. As these decreased, defecation, and freezing increased. 3 Anosmic controls showed that the decrease in social interaction across test conditions could not be attributed to olfactory changes in the partner. 4 Chlordiazepoxide (5 mg/kg) given chronically prevented or significantly reduced the decrease in social interaction that occurred in undrugged rats as the light level or the unfamiliarity of the test box was increased. Controls showed that this effect could not be entirely attributed to chlordiazepoxide acting selectively to increase low levels of responding. 5 The effect of chronic chlordiazepoxide contrasts with its action when given acutely; in the latter case it has only sedative effects. 6 Whether this test can be used as an animal model of anxiety is discussed and this test is compared with existing tests of anxiety.

Hydroxylation of three benzodiazepines in vitro

Three structurally related benzodiazepines were studied as substrates for hydroxylation by liver microsomal enzymes of rats and mice. The Vmax was comparable for dechlorodesmethyldiazepam, desmethyldiazepam, and 2'-chlorodesmethyldiazepam in the two animal species. The apparent Km decreased from dechlorodesmethyldiazepam to 2'-chlorodesmethyldiazepam for liver microsomal enzymes from both animal species. The hydroxylation of desmethyldiazepam and 2'-chlorodesmethyldiazepam yielded two pharmacologically active metabolites, oxazepam and lorazepam, respectively.

Paradoxical fear-increasing effects of tranquilizers: evidence of repression of memory in the rat

Conditioned suppression of feeding, an index of fear, was increased rather than decreased by the administration of benzodiazepine tranquilizers or amobarbital. The drug-induced increase in conditioned fear varied directly with the intensity of the shock used in fear conditioning. The drugs had no fear-increasing effect in unshocked controls or in rats made amnesic by electroconvulsive shock given immediately after fear conditioning. These observations in animals are reminiscent of clinical reports that intraveneous amobarbital facilitates the recall of repressed traumatic experiences. The retrieval of painful memories may be inhibited or repressed in animals as well as in humans. In both cases, tranquilizers may counteract repression by disinhibition of the act of retrieval.