Avoidance behaviour: a predictor of the efficacy of pharmacotherapy in panic disorder?

Benzodiazepines versus placebo for panic disorder in adults

BACKGROUND

Panic disorder is characterised by recurrent unexpected panic attacks consisting of a wave of intense fear that reaches a peak within a few minutes. Panic disorder is a common disorder, with an estimated lifetime prevalence of 1% to 5% in the general population and a 7% to 10% prevalence in primary care settings. Its aetiology is not fully understood and is probably heterogeneous.Panic disorder is treated with psychological and pharmacological interventions, often used in combination. Although benzodiazepines are frequently used in the treatment of panic disorder, guidelines recommend antidepressants, mainly selective serotonin reuptake inhibitors (SSRIs), as first-line treatment for panic disorder, particularly due to their lower incidence of dependence and withdrawal reaction when compared to benzodiazepines. Despite these recommendations, benzodiazepines are widely used in the treatment of panic disorder, probably because of their rapid onset of action.

OBJECTIVES

To assess the efficacy and acceptability of benzodiazepines versus placebo in the treatment of panic disorder with or without agoraphobia in adults.

SEARCH METHODS

We searched the Cochrane Common Mental Disorders Controlled Trials Register (CCMDCTR Studies and References), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1950-), Embase (1974-), and PsycINFO (1967-) up to 29 May 2018. We handsearched reference lists of relevant papers and previous systematic reviews. We contacted experts in the field for supplemental data.

SELECTION CRITERIA

All double-blind (blinding of patients and personnel) controlled trials randomising adults with panic disorder with or without agoraphobia to benzodiazepine or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked the eligibility of studies and extracted data using a standardised form. Data were then entered data into Review Manager 5 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

We included 24 studies in the review with a total of 4233 participants, of which 2124 were randomised to benzodiazepines and 1475 to placebo. The remaining 634 participants were randomised to other active treatments in three-arm trials. We assessed the overall methodological quality of the included studies as poor. We rated all studies as at unclear risk of bias in at least three domains. In addition, we judged 20 of the 24 included studies as having a high risk of bias in at least one domain.Two primary outcomes of efficacy and acceptability showed a possible advantage of benzodiazepines over placebo. The estimated risk ratio (RR) for a response to treatment was 1.65 (95% confidence interval (CI) 1.39 to 1.96) in favour of benzodiazepines, which corresponds to an estimated number needed to treat for an additional beneficial outcome (NNTB) of 4 (95% CI 3 to 7). The dropout rate was lower among participants treated with benzodiazepines (RR 0.50, 95% CI 0.39 to 0.64); the estimated NNTB was 6 (95% CI 5 to 9). We rated the quality of the evidence as low for both primary outcomes. The possible advantage of benzodiazepine was also seen for remission (RR 1.61, 95% CI 1.38 to 1.88) and the endpoint data for social functioning (standardised mean difference (SMD) -0.53, 95% CI -0.65 to -0.42), both with low-quality evidence. We assessed the evidence for the other secondary outcomes as of very low quality. With the exception of the analyses of the change score data for depression (SMD -0.22, 95% CI -0.48 to 0.04) and social functioning (SMD -0.32, 95% CI -0.88 to 0.24), all secondary outcome analyses showed an effect in favour of benzodiazepines compared to placebo. However, the number of dropouts due to adverse effects was higher with benzodiazepines than with placebo (RR 1.58, 95% CI 1.16 to 2.15; low-quality evidence). Furthermore, our analyses of adverse events showed that a higher proportion of participants experienced at least one adverse effect when treated with benzodiazepines (RR 1.18, 95% CI 1.02 to 1.37; low-quality evidence).

AUTHORS' CONCLUSIONS

Low-quality evidence shows a possible superiority of benzodiazepine over placebo in the short-term treatment of panic disorders. The validity of the included studies is questionable due to possible unmasking of allocated treatments, high dropout rates, and probable publication bias. Moreover, the included studies were only short-term studies and did not examine the long-term efficacy nor the risks of dependency and withdrawal symptoms. Due to these limitations, our results regarding the efficacy of benzodiazepines versus placebo provide only limited guidance for clinical practice. Furthermore, the clinician's choice is not between benzodiazepines and placebo, but between benzodiazepines and other agents, notably SSRIs, both in terms of efficacy and adverse effects. The choice of treatment should therefore be guided by the patient's preference and should balance benefits and harms from treatment in a long-term perspective.

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.

Diagnosis and treatment of agoraphobia with panic disorder

Agoraphobia with panic disorder is a phobic-anxious syndrome where patients avoid situations or places in which they fear being embarrassed, or being unable to escape or get help if a panic attack occurs. During the last half-century, agoraphobia has been thought of as being closely linked to the recurring panic attack syndrome, so much so that in most cases it appears to be the typical development or complication of panic disorder. Despite the high prevalence of agoraphobia with panic disorder in patients in primary-care settings, the condition is frequently under-recognised and under-treated by medical providers. Antidepressants have been demonstrated to be effective in preventing panic attacks, and in improving anticipatory anxiety and avoidance behaviour. These drugs are also effective in the treatment of the frequently coexisting depressive symptomatology. Among antidepressant agents, SSRIs are generally well tolerated and effective for both anxious and depressive symptomatology, and these compounds should be considered the first choice for short-, medium- and long-term pharmacological treatment of agoraphobia with panic disorder. The few comparative studies conducted to date with various SSRIs reported no significant differences in terms of efficacy; however, the SSRIs that are less liable to produce withdrawal symptoms after abrupt discontinuation should be considered the treatments of first choice for long-term prophylaxis. Venlafaxine is not sufficiently studied in the long-term treatment of panic disorder, while TCAs may be considered as a second choice of treatment when patients do not seem to respond to or tolerate SSRIs. High-potency benzodiazepines have been shown to display a rapid onset of anti-anxiety effect, having beneficial effects during the first few days of treatment, and are therefore useful options for short-term treatment; however, these drugs are not first-choice medications in the medium and long term because of the frequent development of tolerance and dependence phenomena. Cognitive-behavioural therapy is the best studied non-pharmacological approach and can be applied to many patients, depending on its availability.

The prediction of nonresponse to pharmacotherapy in panic disorder: a review

Several effective pharmacotherapeutic treatments exist for panic disorder; however, not all patients respond to treatment: between 20% to 40% are non-responders. Recent studies have reported several predictors of nonresponse to pharmacotherapy. In this review two questions are addressed: is there consensus with respect to predictors of nonresponse and are there any differences between short-term and long-term predictors? In this review both short-term and long-term outcome studies are discussed. Studies were included if at least DSM-III criteria were used and baseline variables were investigated as possible predictor of response, or nonresponse, to pharmacotherapy. Of each clinical predictor, tallies were made of the particular predictors employed and of those predictors that predicted nonresponse. It appears that a long duration of illness and severe agoraphobic avoidance are robust predictors of nonresponse, particularly in long-term studies. Personality disorders, or even personality traits, are possibly the most robust predictors of nonresponse. Several factors appear to be robust predictors of nonresponse: factors that are present before treatment and exert their influence on short-term and long-term treatment outcome. Prospective studies are needed to further investigate these factors and to test whether it is viable to intervene in an attempt to increase treatment response.

The side effects burden of extended imipramine treatment of panic disorder

In a recent study, the authors gauged the net effectiveness of imipramine to be 53%; that is, of 110 patients having panic disorder with agoraphobia who started a course of imipramine at a fixed, targeted, weight-adjusted dose of 2.25 mg x kg(-1) x day(-1), 59 adhered to the regimen and showed a marked and stable response. The present study investigated in detail the side effects burden of imipramine treatment in the same sample using hierarchical linear modeling in a short-term perspective, based on data at baseline (N = 110) and at weeks 1, 2, 4, 6, and 8 (N = 77) of treatment, and a long-term perspective, based on data at baseline and at weeks 8, 16 (N = 66), and 24 (N = 59). Deviations from the general pattern were explored by considering only severe side effects or only completers of treatment to better gauge the clinical significance of the findings. The results revealed that of 15 complaints systematically elicited using a side effects inventory, only 3--dry mouth, sweating, and constipation--continued as a substantial burden at the end of 6 months of treatment. On most other items, the initial increase was followed by a decrease to lower than baseline at the end of treatment. In the case of nausea, vomiting, increased energy, headache, and sexual disorders, the complaints were at their worst before treatment started and improved over the course of treatment. A sustained heart rate elevation between 10 and 15 beats per minute was found, but there were no significant effects on blood pressure or weight. The discussion underscores the need for more methodologically improved comparative studies with selective serotonin reuptake inhibitors in the treatment of panic disorder.

Cost effectiveness of acute imipramine therapy versus two imipramine maintenance treatment regimens for panic disorder

OBJECTIVE

To examine the medical costs and effectiveness of acute treatment with imipramine versus acute treatment plus 2 different maintenance therapies for panic disorder.

METHODS

A clinical decision model was constructed to estimate 18-month costs and outcomes associated with these treatment scenarios based on the medical literature and clinician judgment. The clinical parameters and outcomes for the model were derived from a series of systematic clinical trials with imipramine utilising uniform dosage procedures and validated response criteria. Costs were calculated based on standardised treatment regimens. The outcome measures were 18-month medical costs, quality-adjusted life years (QALYs) and costs per QALY gained. A sensitivity analysis was performed to explore the impact of treatment withdrawals on outcomes.

STUDY PERSPECTIVE

US mental healthcare system.

RESULTS

Over 18 months, the total costs (1997 values) and QALYs associated with half-dose maintenance therapy (imipramine 1.1 mg/kg/day) [$US3377; QALYs = 0.991] and full-dose maintenance therapy (imipramine 2.25 mg/kg/ day) [$US3361; QALYs = 0.991] were almost identical; both were cost saving compared with acute imipramine therapy (2.25 mg/kg/day) with no maintenance treatment ($US3691; QALYs = 0.979). Whether patients withdrawing from treatment were considered to have continued to respond to treatment or to have relapsed, the half-dose and full-dose maintenance treatments were still cost saving compared with acute treatment alone.

CONCLUSIONS

The results indicate that imipramine maintenance treatment is cost effective compared with acute imipramine treatment for patients with panic disorder. The basic findings and conclusions are not affected after modifying model assumptions for clinical response in patients withdrawing from treatment.

Gauging the effectiveness of extended imipramine treatment for panic disorder with agoraphobia

BACKGROUND

Imipramine has proven efficacy for panic disorder. This study assesses the net effectiveness of systematic, open imipramine treatment in a homogenous sample of panic disorder patients with agoraphobia.

METHODS

One hundred and ten consecutive patients with DSM-III-R moderate to severe panic disorder with agoraphobia were treated with a fixed regimen of imipramine 2.25 mg/kg/day for 24 weeks. No instructions or encouragement for self-directed exposure to phobic situations or other coping strategies with panic or fear were given. Assessments were conducted at the end of the 2-week placebo run-in and at weeks 8, 16, and 24 of treatment.

RESULTS

Overall, 53% had a marked and stable response. Most measures revealed that substantial improvement continued beyond week 8 of treatment. Treatment success was accompanied with significant improvements in anxiety sensitivity, dysphoric mood, and functional well-being.

CONCLUSIONS

These results provide a clinically relevant reference with which to compare the effectiveness of alternative treatments in providing nearly complete symptom remission in patients with primary panic disorder with agoraphobia.

The transfer of avoidance evoking functions through stimulus equivalence classes

Recent research in the area of stimulus equivalence suggests that transfer of function via members of stimulus equivalence classes may have relevance to human emotional responding and the development and generalization of certain psychological disorders. This study investigated the transfer of avoidance evoking functions through equivalence classes. Eight subjects were trained in the necessary relations for two-four member stimulus equivalence classes to emerge. Next, using an on-baseline classical conditioning procedure, one member of one class was paired with shock while one member of the other class was presented without shock. Then, while subjects engaged a key-press task, a differential, signalled avoidance task was introduced wherein shock was avoided if a response occurred to the stimulus previously associated with shock. The remaining stimuli from both classes were then presented. The behavior of all eight subjects showed the differential transfer of the avoidance evoking function. The clinical and theoretical implications of the results are discussed.

The effect of citalopram in panic disorder

BACKGROUND

Citalopram is a serotonin reuptake inhibitor which has been demonstrated to be highly selective and with a superior tolerability profile to the classical tricyclic antidepressants. This study was designed to test whether there was any difference in efficacy in the management of panic disorder (PD) between citalopram and placebo.

METHOD

This was a double-blind, placebo and clomipramine controlled, parallel group eight-week study. A total of 475 patients with PD, with or without agoraphobia, were randomised to treatment with either placebo, clomipramine 60 or 90 mg/day, or citalopram 10 or 15 mg/day, or 20 or 30 mg/day, or 40 or 60 mg/day. Doses were increased over the first three weeks, stabilised during the fourth week and fixed between weeks five and eight.

RESULTS

Treatment with citalopram at 20 or 30 mg, 40 or 60 mg and clomipramine were significantly superior to placebo, judged by the number of patients free of panic attacks in the week prior to the final assessment. All rating scales examined suggested that citalopram 20 or 30 mg was more effective than citalopram 40 or 60 mg.

CONCLUSION

The most advantageous benefit/risk ratio for the treatment of PD was associated with citalopram 20 or 30 mg/day.

Phenomenology of panic attacks: responsiveness of individual symptoms to imipramine

A number of studies have demonstrated that individual panic symptoms are not equivalent vis-a-vis their clinical salience. This study investigated the proposition that individual panic symptoms may also differ in their specific responsiveness to treatment in 63 patients with panic disorder with agoraphobia who had completed an 8-week placebo-controlled dose-ranging study with imipramine. The results revealed that fear, unreality, and respiratory symptoms, most strongly dyspnea and choking, displayed the highest degree of early differentiation between effective and ineffective doses of the drug, whereas palpitations, tingling, and sweating had the most pronounced effects between weeks 4 and 8 of treatment. On the other hand, the symptom of hot and cold flashes did not differ between adequate and inadequate treatment. The evidence presented reinforces the notion that individual panic symptoms are not functionally equivalent and suggests that some symptoms, in particular fear, derealization, and the respiratory symptoms, may be more central than others to the therapeutic process just as some of them have been found to be more important for diagnostic considerations. The results are briefly discussed from the methodologic and phenomenologic perspectives.

Paroxetine in the treatment of panic disorder. A randomised, double-blind, placebo-controlled study

BACKGROUND

This study compared the efficacy and tolerability of paroxetine with placebo in the treatment of panic disorder.

METHOD

After three weeks of placebo, patients received 12 weeks of treatment with paroxetine (20, 40, or 60 mg) or placebo, and finally two weeks of placebo. Dosages were adjusted according to efficacy and tolerability. Standardised cognitive therapy was given to all patients. The primary measure of outcome was reduction in the number of panic attacks.

RESULTS

Analysis of the results showed statistically significant differences in favour of paroxetine between the two treatment groups in two out of the three primary measures of outcome, i.e. 50% reduction in total number of panic attacks and number of panic attacks reduced to one or zero over the study period. For the third measure of outcome, the mean change in the total number of attacks from baseline, there was a positive trend in favour of paroxetine. The results of the primary measures of outcome were strongly supported by the results of the secondary efficacy measures of outcome. In addition, paroxetine, at all doses, was very well tolerated.

CONCLUSION

Paroxetine plus cognitive therapy was significantly more effective than placebo plus cognitive therapy in the treatment of panic disorder.

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.

Anxiety psychopathology predictive of outcome in patients with panic disorder and depression treated with imipramine, alprazolam and placebo

This study examines clinical predictors of outcome for patients with panic disorder and depression in a 16 week, placebo-controlled trial of alprazolam and imipramine (n = 126). Baseline global severity of illness and phobic avoidance were differentially predictive of acute response to treatment. Patients in the mild to moderate range of global distress experienced smaller degrees of improvement on alprazolam than on imipramine at week 4. At endpoint, the relative effectiveness of the active medication versus placebo was diminished in patients with higher levels of phobic avoidance. This relationship was not evident for completers, suggesting that the adverse effects of avoidance on outcome after sustained treatment was reduced.

Pre-treatment predictors of treatment outcome in panic disorder and agoraphobia treated with alprazolam and exposure

Pre-treatment predictors of treatment outcome were examined in a group of 144 patients with panic disorder and agoraphobia randomly allocated to alprazolam+exposure (AE), placebo+exposure (PE), alprazolam+relaxation (AR), and placebo+relaxation (PR). First-time psychotropic medication use, severity of agoraphobic disability, and longer duration of illness predicted less global improvement at post-treatment. Pre-treatment severity of agoraphobia predicted less improvement both in the short- and the long-term. Predictors of poorer outcome at 6-month follow-up were older age, past history of depression, severity of phobia targets, and longer duration of illness. Sex, source of referral, pre-treatment depression-anxiety-panic, and expectancy from treatment did not relate to outcome.

Alprazolam and exposure alone and combined in panic disorder with agoraphobia. A controlled study in London and Toronto

A cross-national randomised trial of alprazolam for chronic panic disorder with agoraphobia was run. Compared with previous trials it had three new features: an exposure therapy contrast group, a six-month treatment-free follow-up, and a low rate of early placebo drop-outs ('non-evaluables'). The dose of alprazolam was high (5 mg/day). The 154 patients had eight weeks of: alprazolam and exposure (combined treatment); or alprazolam and relaxation (a psychological placebo); or placebo and exposure; or placebo and relaxation (double placebo). Drug taper was from weeks 8 to 16. Follow-up was to week 43. Results were similar at both sites. Treatment integrity was good. All four treatment groups, including double placebo, improved well on panic throughout. On non-panic measures, by the end of treatment, both alprazolam and exposure were effective, but exposure had twice the effect size of alprazolam. During taper and follow-up, gains after alprazolam were lost, while gains after exposure were maintained. Combining alprazolam with exposure marginally enhanced gains during treatment, but impaired improvement thereafter. The new features put previous trails in a fresh light. By the end of treatment, though gains on alprazolam were largely as in previous studies, on phobias and disability they were half those with exposure. Relapse was usual after alprazolam was stopped, whereas gains persisted to six-month follow-up after exposure ceased. Panic improved as much with placebo as with alprazolam or exposure.

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.