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1.
PLoS One ; 13(11): e0205485, 2018.
Article in English | MEDLINE | ID: mdl-30481183

ABSTRACT

BACKGROUND: Experience of domestic violence and abuse (DVA) is associated with mental illness. Advocacy has little effect on mental health outcomes of female DVA survivors and there is uncertainty about the effectiveness of psychological interventions for this population. OBJECTIVE: To test effectiveness of a psychological intervention delivered by advocates to DVA survivors. DESIGN, MASKING, SETTING, PARTICIPANTS: Pragmatic parallel group individually randomized controlled trial of normal DVA advocacy vs. advocacy + psychological intervention. Statistician and researchers blinded to group assignment. Setting: specialist DVA agencies; two UK cities. Participants: Women aged 16 years and older accessing DVA services. INTERVENTION: Eight specialist psychological advocacy (SPA) sessions with two follow up sessions. MEASUREMENTS: Primary outcomes at 12 months: depression symptoms (PHQ-9) and psychological distress (CORE-OM). Primary analysis: intention to treat linear (logistic) regression model for continuous (binary) outcomes. RESULTS: 263 women recruited (78 in shelter/refuge, 185 in community), 2 withdrew (1 community, control group; 1 intervention, refuge group), 1 was excluded from the study for protocol violation (community, control group), 130 in intervention and 130 in control groups. Recruitment ended June 2013. 12-month follow up: 64%. At 12-month follow up greater improvement in mental health of women in the intervention group. Difference in average CORE-OM score between intervention and control groups: -3.3 points (95% CI -5.5 to -1.2). Difference in average PHQ-9 score between intervention and control group: -2.2 (95% CI -4.1 to -0.3). At 12 months, 35% of the intervention group and 55% of the control group were above the CORE-OM -2clinical threshold (OR 0.32, 95% CI 0.16 to 0.64); 29% of the intervention group and 46% of the control group were above the PHQ-9 clinical threshold (OR 0.41, 95% CI 0.21 to 0.81). LIMITATIONS: 64% retention at 12 months. CONCLUSIONS: An eight-session psychological intervention delivered by DVA advocates produced clinically relevant improvement in mental health outcomes compared with normal advocacy care. TRIAL REGISTRATION: ISRCTN registry ISRCTN58561170 Original Research 3675/3750.


Subject(s)
Domestic Violence/psychology , Mental Health , Spouse Abuse/psychology , Stress Disorders, Post-Traumatic/psychology , Adolescent , Adult , Aged , Depression/physiopathology , Depression/psychology , Female , Humans , Intimate Partner Violence , Male , Middle Aged , Psychometrics , Stress Disorders, Post-Traumatic/physiopathology , Young Adult
2.
Sex Transm Infect ; 94(2): 88-92, 2018 03.
Article in English | MEDLINE | ID: mdl-28778979

ABSTRACT

OBJECTIVES: Domestic violence and abuse (DVA) is a major clinical challenge and public health issue. Sexual health services are an important potential site of DVA intervention. The Assessing for Domestic Violence in Sexual Health Environments (ADViSE) intervention aimed to improve identification and management of DVA in sexual healthcare settings and is a modified version of the Identification and Referral to Improve Safety (IRIS) general practice programme. Our qualitative evaluation aimed to explore the experiences of staff participating in an IRIS ADViSE pilot. METHODS: Interviews were conducted with 17 sexual health clinic staff and DVA advocate workers. Interviews were audio recorded, transcribed, anonymised and analysed thematically. RESULTS: Staff prioritised enquiring about DVA and tailored their style of enquiry to the perceived characteristics of patients, current workload and individual clinical judgements. Responding to disclosures of abuse was divided between perceived low-risk cases (with quick onwards referral) and high-risk cases (requiring deployment of institution safeguarding procedures), which were viewed as time consuming and could create tensions with patients. Ongoing training and feedback, commissioner recognition, adequate service-level agreements and reimbursements are required to ensure sustainability and wider implementation of IRIS ADViSE. CONCLUSIONS: Challenges of delivering and sustaining IRIS ADViSE included the varied styles of enquiry, as well as tensions and additional time pressure arising from disclosure of abuse. These can be overcome by modifying initial training, providing regular updates and stronger recognition (and resources) at policy and commissioning levels.


Subject(s)
Domestic Violence , General Practice/education , Sexual Health , Ambulatory Care Facilities , Crime Victims , Female , Humans , Interviews as Topic/standards , Male , Qualitative Research , Referral and Consultation , Tape Recording
3.
J Psychopharmacol ; 28(8): 763-72, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24763184

ABSTRACT

Cigarette smoking is associated with elevated risk of anxiety and mood disorder. Using the 7.5% carbon dioxide (CO2) inhalation model of anxiety induction, we examined the effects of smoking status and abstinence from smoking on anxiety responses. Physiological and subjective responses to CO2 and medical air were compared in smokers and non-smokers (Experiment One) and in overnight abstinent and non-abstinent smokers (Experiment Two). CO2 induced greater increases in blood pressure in non-smokers compared with smokers (ps < 0.043), and greater increases in anxiety (p = 0.005) and negative affect (p = 0.054) in non-abstinent compared with abstinent smokers. CO2 increased physiological and subjective indices of anxiety. There were differences across smoking groups indicating that the CO2 inhalation model is a useful tool for examining the relationship between smoking and anxiety. The findings suggested that both acute smoking and acute abstinence may protect against anxious responding. Further investigation is needed in long-term heavy smokers.


Subject(s)
Affect/drug effects , Anxiety/chemically induced , Carbon Dioxide/adverse effects , Hypertension/chemically induced , Smoking/psychology , Affect/physiology , Anxiety/physiopathology , Anxiety/psychology , Blood Pressure/drug effects , Blood Pressure/physiology , Case-Control Studies , Craving/drug effects , Female , Heart Rate/drug effects , Humans , Hypertension/physiopathology , Male , Smoking/physiopathology , Substance Withdrawal Syndrome/psychology , Young Adult
4.
Hum Psychopharmacol ; 28(6): 562-75, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23955418

ABSTRACT

It is generally thought that venlafaxine raises blood pressure at higher doses; however, some studies have found no effect or a decrease in blood pressure. The aim of this study was to evaluate the cardiovascular (CV) effects of 3 weeks of dosing with venlafaxine, pregabalin and placebo on young healthy adults. Fifty-four participants, of mean age 23.1 years (sd 4.68), 29 male, were randomised into three parallel groups. Each group received one of the three drugs, dosed incrementally over a 3-week period to reach daily doses of 150 mg/day venlafaxine and 200 mg/day pregabalin. Blood pressure sphygmomanometer measurements, heart rate measurements, and orthostatic challenges recorded continuously beat-to-beat were performed weekly over this period and 5 days after treatment cessation. Results showed resting systolic blood pressure (SBP) and resting and standing diastolic blood pressure (DBP) and heart rate (HR) were significantly raised by venlafaxine compared with the pregabalin and placebo groups. SBP drop on standing was larger, the resulting overshoot was smaller, and recovery was slower on venlafaxine. HR recovery was significantly impaired by venlafaxine. CV changes were observed after only 1 week of dosing at 112.5 mg/day. These effects of venlafaxine are likely to be due to its action of noradrenergic reuptake inhibition.


Subject(s)
Blood Pressure/drug effects , Cyclohexanols/pharmacology , Heart Rate/drug effects , gamma-Aminobutyric Acid/analogs & derivatives , Adrenergic Uptake Inhibitors/pharmacology , Adult , Calcium Channel Blockers/pharmacology , Double-Blind Method , Female , Humans , Male , Posture/physiology , Pregabalin , Venlafaxine Hydrochloride , Young Adult , gamma-Aminobutyric Acid/pharmacology
5.
J Psychopharmacol ; 27(2): 135-45, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22516666

ABSTRACT

Previous studies have shown that subjective and objective symptoms of anxiety induced by 7.5% CO(2) inhalation can be attenuated by anxiolytics such as lorazepam and, to a lesser extent, paroxetine. Venlafaxine and pregabalin, two other licensed treatments for Generalised Anxiety Disorder, were used to further investigate the 7.5% and 35% CO(2) models of anxiety in healthy volunteers. Fifty-four participants were randomised to receive either placebo, venlafaxine or pregabalin. Study treatments were dosed incrementally over a three week period, to reach daily doses of 150 mg venlafaxine and 200mg pregabalin by the CO(2) challenge test day. Participants inhaled air 7.5% CO(2) for 20 minutes (single-blind presentation), and a non-blinded single vital capacity of 35% CO(2). Subjective ratings were recorded before and after each inhalation. Both 7.5% and 35% CO(2) inhalations produced the expected effects of increased ratings of symptoms of panic and anxiety, with increased blood pressure and heart rate. No significant treatment effects were found, although there were trends towards a reduction in feeling tense and nervous by both drugs compared with placebo during the 7.5% CO(2) challenge, and a reduction in alertness generally in the venlafaxine group compared with the pregabalin group. In contrast with the clear anxiolytic effects of benzodiazepines reported in several previous CO(2) studies, these findings suggest that the anxiogenic effects of CO(2) challenges are not significantly influenced by these serotonergic and GABAergic anxiolytics. This may be due to a lack of sensitivity of the CO(2) challenges in healthy volunteers to these drug types.


Subject(s)
Anxiety Disorders/drug therapy , Cyclohexanols/therapeutic use , Panic/drug effects , gamma-Aminobutyric Acid/analogs & derivatives , Administration, Inhalation , Adult , Anxiety Disorders/chemically induced , Blood Pressure/drug effects , Carbon Dioxide , Cyclohexanols/adverse effects , Double-Blind Method , Female , Heart Rate/drug effects , Humans , Male , Pregabalin , Surveys and Questionnaires , Venlafaxine Hydrochloride , Young Adult , gamma-Aminobutyric Acid/adverse effects , gamma-Aminobutyric Acid/therapeutic use
6.
Hum Psychopharmacol ; 27(6): 540-8, 2012 Nov.
Article in English | MEDLINE | ID: mdl-23027657

ABSTRACT

Symptoms of anxiety induced by 7.5% CO2 inhalation can be attenuated by acute administration of GABA(A) receptor anxiolytics such as lorazepam and alprazolam. This study investigated if these effects are dose-related, by comparing a 0.5 mg dose (considered non-clinically effective) and a 2 mg dose of lorazepam (clinically effective) on 7.5% CO2 inhalation. Eighteen healthy males (mean age 20.6 years, SD 1.29), judged physically and mentally fit, attended three visits, each one week apart, to take each treatment in a randomised double-blind crossover design. Drugs were given 60 min prior to 20 min air inhalation, followed by 20 min 7.5% CO2 inhalation. The order of gas presentation was single blind. Subjective ratings using visual analogue scales (VAS) and questionnaires were recorded before and after each inhalation. Blood pressure (BP), heart rate (HR), respiration rate (RR) and expired CO2 were recorded during each inhalation. Inhalation of 7.5% CO2 significantly raised BP, HR, RR and expired CO2. Ratings of feeling like leaving the room were significantly lower on 2 mg compared with 0.5 mg and placebo, and dose-dependent trends were seen in scores for VAS fearful, anxious, stressed, tense, and worried. Results may be indicative of dose-dependent effects of lorazepam in a CO2 model of anxiety.


Subject(s)
Anti-Anxiety Agents/administration & dosage , Anxiety/prevention & control , Asphyxia/psychology , GABA-A Receptor Agonists/administration & dosage , Lorazepam/administration & dosage , Administration, Inhalation , Adult , Anti-Anxiety Agents/adverse effects , Anti-Anxiety Agents/therapeutic use , Asphyxia/etiology , Carbon Dioxide/administration & dosage , Carbon Dioxide/adverse effects , Cross-Over Studies , Dose-Response Relationship, Drug , Double-Blind Method , GABA-A Receptor Agonists/adverse effects , GABA-A Receptor Agonists/therapeutic use , Humans , Lorazepam/adverse effects , Lorazepam/therapeutic use , Male , Psychiatric Status Rating Scales , Reproducibility of Results , Surveys and Questionnaires , Young Adult
7.
J Psychopharmacol ; 26(4): 487-96, 2012 Apr.
Article in English | MEDLINE | ID: mdl-21890588

ABSTRACT

Studies have shown that anxiety can positively or negatively affect performance with respect to focusing of attention or distractibility, subjective workload and effort (Humphreys and Revelle, 1984). The inhalation of carbon dioxide (CO(2)) is associated with physiological and psychological effects of anxiety (Bailey et al., 2005) but its effects on performance have rarely been reported. The studies reported here looked at the effects of CO(2) inhalation on physiological and subjective measures and performance on two tasks. Eight healthy male participants completed a tracking task with a reaction time component, and 12 healthy participants (six male) completed a complex target identification task. Tasks were performed during 20-min inhalations of 7.5% CO(2)/21% O(2)/71.5% N(2) mixture or medical air. Continuous heart rate and blood pressure measures were taken, in addition to subjective measures of mood and workload. In comparison with air, CO(2) increased heart rate and blood pressure, increased subjective scores of panic, anxiety, fear, and tension, and reduced subjective scores of relaxation and happiness. Attention was focussed when inhaling CO(2) during the simple task, and central demand was greater when inhaling CO(2) during the complex task. Therefore, inhalation of 7.5% CO(2) produces effects on task performance which are consistent with anxiety.


Subject(s)
Carbon Dioxide , Task Performance and Analysis , Administration, Inhalation , Adult , Blood Pressure/drug effects , Female , Heart Rate/drug effects , Humans , Male , Reaction Time/drug effects , Single-Blind Method
8.
J Psychopharmacol ; 25(9): 1192-8, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21994314

ABSTRACT

Anxiety is a complex phenomenon that can represent contextually different experiences to individuals. The experimental modelling in healthy volunteers of clinical anxiety experienced by patients is challenging. Furthermore, defining when and why anxiety (which is adaptive) becomes an anxiety disorder (and hence maladaptive) is the subject of much of the published literature. Observations from animal studies can be helpful in deriving mechanistic models, but gathering evidence from patients and reverse translating this to healthy volunteers and thence back to laboratory models is a more powerful approach and is likely to more closely model the clinical disorder. Thus the development and validation of a robust healthy volunteer model of anxiety may help to bridge the gap between the laboratory and the clinic and provide 'proof of concept' in screening for novel drug treatments. This review considers these concepts and outlines evidence from a validated healthy volunteer model of generalized anxiety disorder (GAD) following the inhalation of 7.5% CO(2).


Subject(s)
Anti-Anxiety Agents/pharmacology , Anxiety Disorders/physiopathology , Carbon Dioxide/administration & dosage , Administration, Inhalation , Animals , Anxiety Disorders/chemically induced , Drug Design , Healthy Volunteers , Human Experimentation , Humans , Translational Research, Biomedical/methods , Validation Studies as Topic
9.
J Psychopharmacol ; 25(9): 1199-206, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21555331

ABSTRACT

We have validated the use of prolonged inhalation of 7.5% carbon dioxide (CO(2)) as a human model of anxiety and have shown that drugs from two prototypical classes of anxiolytics, benzodiazepines and a serotonin reuptake inhibitor, attenuate CO(2)-induced symptoms (Bailey et al., 2007a). Preclinical evidence suggests that drugs acting at the corticotropin-releasing factor (CRF) system may be useful for the treatment of depression, anxiety, and other stress-related disorders (Valdez, 2006), hence we have now examined the effects of a CRF(1) receptor antagonist in the 7.5% CO(2) model. In a randomized double-blind, placebo-controlled, study in 32 healthy participants we examined the effects of 7 days of treatment with the CRF(1) receptor antagonist, R317573, at a dose that shows a favourable safety profile and is comparable with those effective in preclinical models (40 mg). On day 8, eight of the placebo-treated group received lorazepam (LZP) 2 mg as a positive control. All participants underwent 20 min inhalation of 7.5% CO(2)-enriched air. Subjective reports of peak gas effects were assessed using visual analogue scales and questionnaires. The mean age of participants was 26 years, and 13 were male. The peak effects of CO(2) were expressed as a difference from baseline scores obtained while breathing air alone. Compared with placebo (PLAC), both drug groups showed a decrease in all subjective symptoms, total score on the panic symptom inventory (CRF 11 [2.6], PLAC 16.4 [3.1], LZP 2.9 [3.0]) and a generalized anxiety disorder symptom scale (CRF 2.2 [1.5], PLAC 8.2 [2.2], LZP 1.1 [1.5]). We have shown that a drug that acts to inhibit the CRF(1) receptor shows efficacy in the 7.5% CO(2) model of anxiety in healthy participants.


Subject(s)
Anti-Anxiety Agents/pharmacology , Anxiety/drug therapy , Carbon Dioxide/administration & dosage , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Administration, Inhalation , Adult , Anti-Anxiety Agents/adverse effects , Anxiety/chemically induced , Anxiety/physiopathology , Double-Blind Method , Female , Human Experimentation , Humans , Lorazepam/pharmacology , Male , Surveys and Questionnaires , Young Adult
10.
Cogn Emot ; 25(4): 626-38, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21547765

ABSTRACT

Increased vigilance to threat-related stimuli is thought to be a core cognitive feature of anxiety. We sought to investigate the cognitive impact of experimentally induced anxiety, by means of a 7.5% CO(2) challenge, which acts as an unconditioned anxiogenic stimulus, on attentional bias for positive and negative facial cues of emotional expression in the dot-probe task. In two experiments we found robust physiological and subjective effects of the CO(2) inhalation consistent with the claim that the procedure reliably induces anxiety. Data from the dot-probe task demonstrated an attentional bias to emotional facial expressions compared with neutral faces regardless of valence (happy, angry, and fearful). These attentional effects, however, were entirely inconsistent in terms of their relationship with induced anxiety. We conclude that the previously reported poor reliability of this task is the most parsimonious explanation for our conflicting findings and that future research should develop a more reliable paradigm for measuring attentional bias in this field.


Subject(s)
Attention/drug effects , Carbon Dioxide/pharmacology , Cognition/drug effects , Emotions/drug effects , Facial Expression , Adult , Anger/drug effects , Anxiety/chemically induced , Anxiety/psychology , Carbon Dioxide/administration & dosage , Cues , Fear/drug effects , Fear/psychology , Female , Happiness , Humans , Male , Neuropsychological Tests , Pattern Recognition, Visual/drug effects , Reaction Time , Space Perception/drug effects
11.
Pharmacol Biochem Behav ; 90(1): 51-7, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18485466

ABSTRACT

The mechanisms by which the inhalation of carbon dioxide (CO(2)) produces anxiety and panic are not fully understood, although more recently there is evidence to suggest the involvement of a neural 'fear circuit'. We have suggested that this neural fear circuit is partly mediated by the brain noradrenaline network [Bailey, J.E., Argyropoulos, S.V., Lightman, S.L. and Nutt, D.J., (2003) Does the brain noradrenaline network mediate the effects of the CO(2) challenge? J Psychopharmacol 17(3): 252-259.]. However, we now review evidence that GABA-A may also play an important role in the modulation of CO(2)-induced anxiety. The review of this evidence starts with a key publication showing that 1 min of 35% CO(2)/65% air produced anxiogenic effects in a rat model of anxiety, to a similar extent to the anxiogenic betacarboline derivative FG7142, a benzodiazepine receptor inverse agonist. The effects of both anxiogenic stimuli were abolished with pre-treatment with alprazolam (0.5 mg/kg), but only those of FG7142, not CO(2), was blocked by a benzodiazepine antagonist [Cuccheddu, T., Floris, S., Serra, M., Porceddu, L., Sanna, E., Biggio, G., (1995) Proconflict effect of carbon dioxide inhalation in rats. Life Sci 56: PL 321-324.]. Although the evidence from this study did not conclusively prove that CO(2) had an action to reduce GABA function, it was an experiment designed to be translational to compare what was known about CO(2)-induced anxiety in patients, and to also to explore if GABA mechanisms are involved. Additional evidence from the literature is found in the association between GABA and chemoreceptors, both in laboratory and human studies and GABA and anxiety disorders. Evidence of this association is found across species from stress-induced change in GABA levels in plants and insects to humans, where there is now much evidence of abnormalities in GABA/benzodiazepine receptors in anxiety and other psychiatric disorders. This paper reviews some of the evidence and attempts to relate and compare these findings across species from the human to the Drosophila.


Subject(s)
Anxiety/psychology , Carbon Dioxide/pharmacology , Receptors, GABA-A/physiology , Administration, Inhalation , Animals , Anti-Anxiety Agents/pharmacology , Anxiety/chemically induced , Benzodiazepines/pharmacology , Carbon Dioxide/administration & dosage , Humans , Models, Psychological , Receptors, Serotonin/drug effects , Receptors, Serotonin/physiology , Species Specificity , gamma-Aminobutyric Acid/pharmacology , gamma-Aminobutyric Acid/physiology
12.
J Psychopharmacol ; 21(1): 42-9, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16533865

ABSTRACT

The inhalation of 7.5% carbon dioxide (CO2) in healthy subjects produces an increase in blood pressure and heart rate, and increased feelings of anxiety, fear and tension (Bailey et al. 2005). As this state is similar to that of general anxiety rather than panic, we further validated this by examining the effects of anxiolytic medication. Two separate studies in healthy volunteers are described; study one is a double-blind, placebo-controlled study of a single dose of 2 mg lorazepam and study two describes the effects of 21 days of treatment with paroxetine. Gas challenges were air and 7.5% CO2 inhaled for 20 minutes, delivered on day 0 (before treatment) and day 21 (after treatment) in the paroxetine study. Subjective effects were measured using visual analogue scales and questionnaires. When compared with placebo, lorazepam 2 mg significantly reduced peak CO2-induced subjective fear, feelings of wanting to leave, tension and worry. In the paroxetine study, when compared with day 0, day 21 showed a significantly attenuated peak CO2-induced nervousness and a trend for reduced ratings of anxiety, fear, feel like leaving, tense and worried. In these studies we have shown that this CO2 model of anxiety is sensitive to lorazepam and to a lesser extent paroxetine. This gives support to its utility as an experimental model of general anxiety disorder in healthy volunteers.


Subject(s)
Anti-Anxiety Agents/therapeutic use , Anxiety Disorders/chemically induced , Anxiety Disorders/drug therapy , Carbon Dioxide/adverse effects , Lorazepam/therapeutic use , Paroxetine/therapeutic use , Selective Serotonin Reuptake Inhibitors/therapeutic use , Administration, Inhalation , Adult , Anxiety Disorders/psychology , Carbon Dioxide/administration & dosage , Double-Blind Method , Humans , Male , Psychiatric Status Rating Scales , Reference Values , Time Factors , Treatment Outcome
13.
J Psychopharmacol ; 19(6): 609-13, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16272182

ABSTRACT

The partial agonist buspirone has a REM (rapid eye movement) suppressing effect on human sleep probably via a 5HT(1A) receptor in the pontine area. Eptapirone is a new 5HT(1A) agonist with a greater intrinsic effect than buspirone. The objective of this study was to examine the effects of eptapirone on sleep architecture, particularly REM sleep, in normal volunteers and compare it with buspirone and placebo. This was a randomized, double-blind placebo-controlled four-way crossover study in 12 healthy volunteers. Volunteers were screened to ensure that they had normal overnight sleep EEG (electroencephalogram) and were extensive CYP 2D6 metabolizers. Sleep was recorded on pairs of nights on four occasions, with medication being taken before the second night. Treatments were eptapirone 1.5mg at 10 AM, eptapirone 1.5mg at 11 PM, buspirone 20mg at 11 PM and placebo. Standard measures of sleep were derived and compared among the four treatments using ANOVA. REM sleep was significantly suppressed supporting the proposition that activation of post-synaptic 5HT(1A) receptors reduces REM sleep. Sleep fragmentation increased by both drugs. REM sleep suppression was significantly greater with morning eptapirone than with buspirone. Wakefulness in sleep was significantly greatest after morning eptapirone. REM sleep effects were greatest after evening eptapirone, suggesting a greater effect on central serotonin receptors than that of buspirone.


Subject(s)
Buspirone/pharmacology , Polysomnography , Pyrimidines/pharmacology , Serotonin 5-HT1 Receptor Agonists , Serotonin Receptor Agonists/pharmacology , Sleep Stages/drug effects , Sleep, REM/drug effects , Triazines/pharmacology , Adolescent , Adult , Arousal/drug effects , Attention/drug effects , Cross-Over Studies , Double-Blind Method , Drug Administration Schedule , Humans , Male , Reaction Time/drug effects , Wakefulness/drug effects
14.
Depress Anxiety ; 21(1): 18-25, 2005.
Article in English | MEDLINE | ID: mdl-15782425

ABSTRACT

The study of carbon dioxide (CO2) inhalation in psychiatry has a long and varied history, with recent interest in using inhaled CO2 as an experimental tool to explore the neurobiology and treatment of panic disorder. As a consequence, many studies have examined the panic-like response to the gas either using the single or double breath 35% CO2 inhalation or 5-7% CO2 inhaled for 15-20 min, or rebreathing 5% CO2 for a shorter time. However, this lower dose regime produces little physiological or psychological effects in normal volunteers. For this reason we have studied the effects of a higher concentration of CO2, 7.5%, given over 20 min. Twenty healthy volunteers were recruited to a double blind, placebo-controlled study where air and 7.5% CO2 were inhaled for 20 min. Cardiovascular measures and subjective ratings were obtained. When compared to air, inhaling 7.5% CO2 for 20 min increases systolic blood pressure and heart rate, indicating increased autonomic arousal. It also increases ratings of anxiety and fear and other subjective symptoms associated with an anxiety state. The inhalation of 7.5% CO2 for 20 min is safe for use in healthy volunteers and produces robust subjective and objective effects. It seems promising as an anxiety provocation test that could be beneficial in the study of the effects of anxiety on sustained performance, the discovery of novel anxiolytic agents, and the study of brain circuits and mechanisms of anxiety.


Subject(s)
Anxiety/chemically induced , Anxiety/psychology , Blood Pressure/drug effects , Carbon Dioxide/adverse effects , Heart Rate/drug effects , Panic Disorder/chemically induced , Panic Disorder/psychology , Administration, Inhalation , Adult , Anxiety/diagnosis , Carbon Dioxide/administration & dosage , Female , Humans , Male , Panic Disorder/diagnosis
15.
J Psychopharmacol ; 18(3): 291-2, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15358974
17.
Psychoneuroendocrinology ; 27(6): 715-29, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12084664

ABSTRACT

BACKGROUND: The hypothalamo-pituitary-adrenal (HPA) axis is a major stress responsive system in humans. Although there are numerous ways of testing responsiveness of the HPA in experimental animals, this is much more difficult in man. Hypercapnea is a very stressful stimulus for humans and has been used as an anxiogenic probe in psychiatric patients. We have now investigated whether the simple challenge of a single 35% inhalation of CO(2) activates the neuroendocrine system as evidenced by changes in HPA activity, as well as cardiovascular and subjective responses, in healthy volunteers. METHODS: Fourteen healthy male volunteers were recruited. They underwent single vital capacity inhalation of room air and 35% CO(2), in a single blind fashion. Neuroendocrine, cardiovascular and subjective fear measures were taken at regular intervals. RESULTS: CO(2) inhalation produced significant activation of the HPA axis in all subjects, as measured with plasma cortisol. Heart rate was decreased and systolic blood pressure was significantly increased shortly after the inhalation of CO(2). The subjects reported short-lived symptoms of fear with the experimental gas. CONCLUSIONS: Single vital capacity inhalation of 35% CO(2) activated the HPA axis in healthy volunteers. It also had a significant cardiovascular and psychological (anxiogenic) effect, as expected from previous published studies. The test is potentially useful in studying the responsivity of the HPA axis in health and disease.


Subject(s)
Adrenal Glands/drug effects , Carbon Dioxide/administration & dosage , Hypothalamus/drug effects , Pituitary Gland/drug effects , Administration, Inhalation , Adrenal Glands/physiology , Adult , Blood Pressure/drug effects , Fear , Heart Rate/drug effects , Humans , Hydrocortisone/blood , Hypothalamus/physiology , Male , Panic Disorder , Pituitary Gland/physiology , Placebos
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