The sequence of improvement of the symptoms encountered in patients with panic disorder

Antidepressants versus placebo for panic disorder in adults

BACKGROUND

Panic disorder is characterised by repeated, unexpected panic attacks, which represent a discrete period of fear or anxiety that has a rapid onset, reaches a peak within 10 minutes, and in which at least four of 13 characteristic symptoms are experienced, including racing heart, chest pain, sweating, shaking, dizziness, flushing, stomach churning, faintness and breathlessness. It is common in the general population with a lifetime prevalence of 1% to 4%. The treatment of panic disorder includes psychological and pharmacological interventions. Amongst pharmacological agents, the National Institute for Health and Care Excellence (NICE) and the British Association for Psychopharmacology consider antidepressants, mainly selective serotonin reuptake inhibitors (SSRIs), as the first-line treatment for panic disorder, due to their more favourable adverse effect profile over monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). Several classes of antidepressants have been studied and compared, but it is still unclear which antidepressants have a more or less favourable profile in terms of effectiveness and acceptability in the treatment of this condition.

OBJECTIVES

To assess the effects of antidepressants for panic disorder in adults, specifically:1. to determine the efficacy of antidepressants in alleviating symptoms of panic disorder, with or without agoraphobia, in comparison to placebo;2. to review the acceptability of antidepressants in panic disorder, with or without agoraphobia, in comparison with placebo; and3. to investigate the adverse effects of antidepressants in panic disorder, with or without agoraphobia, including the general prevalence of adverse effects, compared to placebo.

SEARCH METHODS

We searched the Cochrane Common Mental Disorders' (CCMD) Specialised Register, and CENTRAL, MEDLINE, EMBASE and PsycINFO up to May 2017. We handsearched reference lists of relevant papers and previous systematic reviews.

SELECTION CRITERIA

All double-blind, randomised, controlled trials (RCTs) allocating adults with panic disorder to antidepressants or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked eligibility and extracted data using a standard form. We entered data into Review Manager 5 using a double-check procedure. Information extracted included study characteristics, participant characteristics, intervention details and settings. Primary outcomes included failure to respond, measured by a range of response scales, and treatment acceptability, measured by total number of dropouts for any reason. Secondary outcomes included failure to remit, panic symptom scales, frequency of panic attacks, agoraphobia, general anxiety, depression, social functioning, quality of life and patient satisfaction, measured by various scales as defined in individual studies. We used GRADE to assess the quality of the evidence for each outcome MAIN RESULTS: Forty-one unique RCTs including 9377 participants overall, of whom we included 8252 in the 49 placebo-controlled arms of interest (antidepressant as monotherapy and placebo alone) in this review. The majority of studies were of moderate to low quality due to inconsistency, imprecision and unclear risk of selection and performance bias.We found low-quality evidence that revealed a benefit for antidepressants as a group in comparison with placebo in terms of efficacy measured as failure to respond (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.66 to 0.79; participants = 6500; studies = 30). The magnitude of effect corresponds to a number needed to treat for an additional beneficial outcome (NNTB) of 7 (95% CI 6 to 9): that means seven people would need to be treated with antidepressants in order for one to benefit. We observed the same finding when classes of antidepressants were compared with placebo.Moderate-quality evidence suggested a benefit for antidepressants compared to placebo when looking at number of dropouts due to any cause (RR 0.88, 95% CI 0.81 to 0.97; participants = 7850; studies = 30). The magnitude of effect corresponds to a NNTB of 27 (95% CI 17 to 105); treating 27 people will result in one person fewer dropping out. Considering antidepressant classes, TCAs showed a benefit over placebo, while for SSRIs and serotonin-norepinephrine reuptake inhibitor (SNRIs) we observed no difference.When looking at dropouts due to adverse effects, which can be considered as a measure of tolerability, we found moderate-quality evidence showing that antidepressants as a whole are less well tolerated than placebo. In particular, TCAs and SSRIs produced more dropouts due to adverse effects in comparison with placebo, while the confidence interval for SNRI, noradrenergic reuptake inhibitors (NRI) and other antidepressants were wide and included the possibility of no difference.

AUTHORS' CONCLUSIONS

The identified studies comprehensively address the objectives of the present review.Based on these results, antidepressants may be more effective than placebo in treating panic disorder. Efficacy can be quantified as a NNTB of 7, implying that seven people need to be treated with antidepressants in order for one to benefit. Antidepressants may also have benefit in comparison with placebo in terms of number of dropouts, but a less favourable profile in terms of dropout due to adverse effects. However, the tolerability profile varied between different classes of antidepressants.The choice of whether antidepressants should be prescribed in clinical practice cannot be made on the basis of this review.Limitations in results include funding of some studies by pharmaceutical companies, and only assessing short-term outcomes.Data from the present review will be included in a network meta-analysis of psychopharmacological treatment in panic disorder, which will hopefully provide further useful information on this issue.

Antidepressants and benzodiazepines for panic disorder in adults

BACKGROUND

A panic attack is a discrete period of fear or anxiety that has a rapid onset, reaches a peak within 10 minutes and in which at least four of 13 characteristic symptoms are experienced, including racing heart, chest pain, sweating, shaking, dizziness, flushing, stomach churning, faintness and breathlessness. Panic disorder is common in the general population with a lifetime prevalence of 1% to 4%. The treatment of panic disorder includes psychological and pharmacological interventions. Amongst pharmacological agents, antidepressants and benzodiazepines are the mainstay of treatment for panic disorder. Different classes of antidepressants have been compared; and the British Association for Psychopharmacology, and National Institute for Health and Care Excellence (NICE) consider antidepressants (mainly selective serotonin reuptake inhibitors (SSRIs)) as the first-line treatment for panic disorder, due to their more favourable adverse effect profile over monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). In addition to antidepressants, benzodiazepines are widely prescribed for the treatment of panic disorder.

OBJECTIVES

To assess the evidence for the effects of antidepressants and benzodiazepines for panic disorder in adults.

SEARCH METHODS

The Specialised Register of the Cochrane Common Mental Disorders Group (CCMDCTR) to 11 September 2015. This register includes relevant randomised controlled trials from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1950-), Embase (1974-) and PsycINFO (1967-). Reference lists of relevant papers and previous systematic reviews were handsearched. We contacted experts in this field for supplemental data.

SELECTION CRITERIA

All double-blind randomised controlled trials allocating adult patients with panic disorder to antidepressants or benzodiazepines versus any other active treatment with antidepressants or benzodiazepines.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked eligibility and extracted data using a standard form. Data were entered in RevMan 5.3 using a double-check procedure. Information extracted included study characteristics, participant characteristics, intervention details, settings and outcome measures in terms of efficacy, acceptability and tolerability.

MAIN RESULTS

Thirty-five studies, including 6785 participants overall (of which 5365 in the arms of interest (antidepressant and benzodiazepines as monotherapy)) were included in this review; however, since studies addressed many different comparisons, only a few trials provided data for primary outcomes. We found low-quality evidence suggesting no difference between antidepressants and benzodiazepines in terms of response rate (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.67 to 1.47; participants = 215; studies = 2). Very low-quality evidence suggested a benefit for benzodiazepines compared to antidepressants in terms of dropouts due to any cause, even if confidence interval (CI) ranges from almost no difference to benefit with benzodiazepines (RR 1.64, 95% CI 1.03 to 2.63; participants = 1449; studies = 7). We found some evidence suggesting that serotonin reuptake inhibitors (SSRIs) are better tolerated than TCAs (when looking at the number of patients experiencing adverse effects). We failed to find clinically significant differences between individual benzodiazepines. The majority of studies did not report details on random sequence generation and allocation concealment; similarly, no details were provided about strategies to ensure blinding. The study protocol was not available for almost all studies so it is difficult to make a judgment on the possibility of outcome reporting bias. Information on adverse effects was very limited.

AUTHORS' CONCLUSIONS

The identified studies are not sufficient to comprehensively address the objectives of the present review. The majority of studies enrolled a small number of participants and did not provide data for all the outcomes specified in the protocol. For these reasons most of the analyses were underpowered and this limits the overall completeness of evidence. In general, based on the results of the current review, the possible role of antidepressants and benzodiazepines should be assessed by the clinician on an individual basis. The choice of which antidepressant and/or benzodiazepine is prescribed can not be made on the basis of this review only, and should be based on evidence of antidepressants and benzodiazepines efficacy and tolerability, including data from placebo-controlled studies, as a whole. Data on long-term tolerability issues associated with antidepressants and benzodiazepines exposure should also be carefully considered.The present review highlights the need for further higher-quality studies comparing antidepressants with benzodiazepines, which should be conducted with high-methodological standards and including pragmatic outcome measures to provide clinicians with useful and practical data. Data from the present review will be included in a network meta-analysis of psychopharmacological treatment in panic disorder, which will hopefully provide further useful information on this issue.

Agoraphobia is a disease: a tribute to Sir Martin Roth

The evidence which has accumulated on the course of agoraphobia challenges the DSM view that phobic avoidance is secondary to panic attacks. In particular, a longitudinal study by Wittchen et al. indicates that agoraphobia, as a diagnostic category, is frequently independent of panic disorder and panic attacks, is unlikely to remit spontaneously and entails compromised quality of life. A staging system of agoraphobia is presented. Panic may ensue in the longitudinal development of agoraphobia, as well as of other anxiety disorders, and be conceptualized as a potential outcome in the course of anxiety, phobias and hypochondriasis as more than a specific disease entity. These recent research findings confirm the clinical observations and phenomenological research of Sir Martin Roth (1917-2006) and call for a reassessment of the concept of neurosis.

Patterns of change during cognitive behavioral treatment for panic disorder

The present investigation examined patterns of change in basic features of panic and anxiety during cognitive behavioral treatment for panic disorder. Data were collected in the context of a study comparing the efficacy of cognitive therapy (CT) and relaxation training, both administered without exposure-based treatments of any kind. Thirty-six panic disorder patients completed 10 weeks of either CT or relaxation training. Weekly measures of panic frequency, state and trait anxiety, and associated fears were obtained. Data were examined using both multivariate techniques (which conceptualize change as incremental) and analysis of response slopes (wherein change is conceptualized as continuous). Results indicated that during the first half of treatment, relaxation training led to greater reductions in state and trait anxiety and agoraphobic fear, whereas CT demonstrated a slight advantage on change in panic frequency. During the second half of treatment, CT produced faster reductions in state anxiety and agoraphobic fears. Over the entire treatment course, CT conferred an advantage in rate of change in social fears. The data provide support for the utility of a more process-oriented approach to the examination of treatment effects.

The symptom structure of panic disorder: a trial using factor and cluster analysis

Using cluster analysis of 207 patients with panic disorder (PD), we investigated the relationships between several panic symptoms at the time of panic attacks, which included anticipatory anxiety, agoraphobia, and 13 clinical symptoms based on the Diagnostic and Statistics Manual-III-Revised. Cluster analysis revealed three panic symptom clusters: cluster A (dyspnea, choking, sweating, nausea, flushes/chills); cluster B (dizziness, palpitations, trembling or shaking, depersonalization, agoraphobia, and anticipatory anxiety); and cluster C (fear of dying, fear of going crazy, paresthesias, and chest pain or discomfort). Generally, cluster A was comprised exclusively of physiological symptoms, among which respiratory symptoms were prominent, cluster B included both panic and non-panic symptoms such as agoraphobia and anticipatory anxiety, and cluster C was comprised chiefly of fear symptoms.

Alprazolam and exposure for panic disorder with agoraphobia. Attribution of improvement to medication predicts subsequent relapse

Patients with panic disorder plus agoraphobia had 8 weeks of drug treatment (alprazolam or placebo) plus psychological treatment (exposure or relaxation). At the end of treatment at week 8, 40 patients who had become much/very much improved rated how much their gains were attributable to medication or to their own efforts. During the tapering-off to week 16, and treatment-free follow-up to week 43, patients who at week 8 had attributed their gains to medication and felt less confident in coping without tablets had more severe withdrawal symptoms and greater loss of gains than did patients who at week 8 had attributed their gains to their own efforts during treatment. Baseline illness severity, greater age, higher expectations from drug treatment, and more side-effects of drugs during treatment all predicted more external attributions (i.e. to the effect of drugs) but did not independently predict relapse. Patients on alprazolam compared with placebo had more drug attributions. Though drug attributions predicted relapse in both alprazolam and placebo groups, predictions were stronger in the alprazolam group.

Drug treatment of panic disorder

Drug treatment of panic disorder is reviewed with focus on recent controlled studies. The efficacy of alprazolam, a triazolobenzodiazepine, and imipramine, a tricyclic antidepressant, has consistently been demonstrated, but there is reasonable evidence that other benzodiazepines or antidepressants might also be effective if equipotent doses are used. Most controlled studies demonstrate drug efficacy on several psychopathological symptoms, including the core symptom panic attacks. Limited evidence indicates that alprazolam may be more efficacious in treating panic attacks than avoidance behaviour, and the reverse when imipramine is concerned. Drug efficacy appears to be most consistently documented in moderately to severely ill panic patients. The benzodiazepines are better tolerated than antidepressants in terms of patient acceptance, and the improvement sets in faster with benzodiazepines. In the presence of depressive symptoms considered secondary to panic attacks and/or agoraphobia, both types of drugs appear efficacious. Difficulty discontinuing high-dose benzodiazepine treatment remains the most important side effect of the treatment but sedation can, like anticholinergic side effects of the tricyclic antidepressants, be troublesome, thereby diminishing patient compliance. The role of newly developed antidepressants with a more specific mode of action and milder side effects awaits evaluation in controlled trials.