Institute of Psychiatry, University of São Paulo, Brazil
Institute of Psychiatry, London, UK
Correspondence: Ligia Montenegro Ito, Ambulatorio de Ansiedade (AMBAN), Instituto de Psiquiatria, Hospital das Clinicas da Faculdade de Medicina, Universidade de São Paulo, Cep 05403-010, São Paulo, Brazil
Declaration of interest Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).
* Presented at the XXVII Congress of European Association for Behavioural
& Cognitive Therapies, Venice, Italy, 26 September 1997.
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ABSTRACT |
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Aims Randomised controlled comparison in panic/agoraphobia of the effects of (a) external, (b) interceptive or (c) combined external and interoceptive self-exposure to (d) control subjects.
Method Eighty out-patients were randomised to a control group or to one of three forms of self-exposure treatment (external, interoceptive, or combined). Each treatment included seven sessions over 10 weeks and daily self-exposure homework. Assessments were at pre- and post-treatment and up to 1 year post-enty. Assessors remained blind during treatment.
Results The three self-exposure groups improved significantly and similarly at post-treatment and up to 1-year followup, and significantly more than did the control subjects. Rates of improvement on main outcome measures averaged 60% at post-treatment and 77% at follow-up.
Conclusions The three methods of self-exposure were equally effective in reducing panic and agoraphobic symptoms in the short- and long-term.
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INTRODUCTION |
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The present study compares self-exposure to external cues, to interoceptive cues, and to both combined, and compares those three self-exposure conditions with a control group. Both interoceptive groups were trained in slow deep breathing after self-exposure to interoceptive cues.
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METHOD |
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Subjects
These were mostly self-referred (69%) out-patients who sought help after
reading an article in the lay press. Inclusion criteria were panic disorder
with agoraphobia (semi-structured interview based on DSMIV criteria;
American Psychiatric Association,
1994) for at least 1 year; age 18 to 65; absence of suicidal
intent, organic brain disease, past or present psychosis, psychotropic
medication or excess alcohol (ingestion of 30 or more alcohol units/week); no
response to exposure in the past 2 years; no other current psychotherapy.
Patients on benzodiazepines had to withdraw and be drug-free for at least 2
weeks before study entry because of the drugs' negative interaction with
exposure treatments. Those on a stable dose of antidepressant without
improvement for at least 12 weeks were asked to maintain that dose throughout
the study. The study protocol was approved by the university ethics
committee.
Referred patients had a 1-hour screening interview for diagnosis and clinical features, and knew they might enter the untreated control group for 10 weeks. Suitable patients gave written consent and were self- and assessor-rated (by L.M.I. and L.A.D.A.) and then randomly assigned in permuted blocks (Pocock, 1990) to groups E, I, E+I or control for balance.
Therapists used procedure and treatment manuals (Barlow & Craske, 1988) covering each session for each condition. Groups E, I and E+I patients had seven treatment sessions at weeks 0, 1, 2, 4, 6, 8 and 10.
At week 0, all self-exposure patients (groups E, I and E+I) met the therapist, who explained that panics are part of an anxiety response with behavioural and physical symptoms which can be unpleasant but not dangerous. A self-exposure rationale corresponding to E, I or E+I conditions was also given on a printed sheet that patients were asked to read. Group I and group E+I patients were taught to slow their breathing to lower anxiety after interoceptive exposure exercises.
At sessions 1 and 2 (weeks 0 and 1) the therapist spent 45 minutes with the patient encouraging appropriate exposure and 15 minutes negotiating appropriate homework tasks. Sessions 3-7 lasted 30-45 minutes, with the therapist monitoring and negotiating appropriate self-exposure homework. Groups E, I and E+I patients had the same duration of within-session self-exposure and were asked to do self-exposure homework corresponding to E, I or E+I conditions for 60 minutes daily between sessions. At the end of treatment (week 10), all self-exposure patients were told to continue during follow-up their type of self-exposure homework and to keep a diary of this (to control for the amount of exposure to tasks) to week 62 (1-year follow-up).
Self-exposure to external cues (group E)
At sessions 1 and 2, patients had 45 minutes of therapist-accompanied
exposure to feared external situations, until discomfort diminished, and 15
minutes planning homework tasks.
Self-exposure to interoceptive cues (group I)
At sessions 1 and 2, patients had 45 minutes of therapist-accompanied
interoceptive exposure exercises and 15 minutes planning interoceptive
homework tasks. The therapist showed patients how to induce sensations like
those experienced during their panics (e.g. rapid breathing, palpitations,
dizziness) by (a) hyperventilating for up to a minute; (b) shaking their head
from side to side for 30 seconds; (c) running on the spot for a minute; (d)
putting their head between their legs for 30 seconds and then quickly lifting
it up; (e) spinning in a chair for a minute. Patients were asked to rate how
intense and similar the sensations so induced were to their usual panic
feelings. They were told to stop any exercise which produced sensations
without anxiety. After each exercise they learned to use slow breathing to
return to their baseline anxiety level. Patients were told that their fear
would lessen after they induced such sensations repeatedly in a neutral
environment.
Self-exposure to both external and interoceptive cues (group
E+I)
At sessions 1 and 2, patients had 30 minutes of therapist-accompanied
exposure to the frightening external situations while remaining there until
discomfort diminished, 15 minutes of therapist-accompanied interoceptive
exposure plus training in slow breathing, and 15 minutes negotiating
appropriate daily homework tasks comprising 30 minutes of live exposure and 30
minutes of interoceptive exposure.
Control group
At session 1 patients were told that their symptoms could improve without
treatment and that they would have to wait for 10 weeks to receive treatment
if they still needed it after that period. They could return for advice if
their clinical condition worsened.
The therapists
These were four psychiatrists and a psychologist experienced in behaviour
therapy for anxiety disorders. A psychiatrist (L.A.D.A.) and a clinical
psychologist (L.M.I.) treated most of the patients, each treating similar
numbers across the four treatment conditions over 3 years.
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ASSESSMENT |
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Measures
These were validated reliable scales used in past trials. Higher scores
denoted more abnormality.
Assessor- and self-ratings were of: two phobic targets (Gelder & Marks, 1966), for avoidance and for fear (each score range 0-16); four work/social adjustment items (Marks, 1975), each scored 0-8 (total score range 0-32).
Self-ratings were of: Fear Questionnaire (FQT; Marks & Mathews, 1979), containing 15 phobic avoidance 0-8 items (total score range 0-120) and including five agoraphobic items making up an agoraphobia subscore (FQAg), range 0-40; Agoraphobic Cognitions Questionnaire (Chambless et al, 1984) for frequency, score range 14-70; diary of panic (DSM-IV criteria) frequency over 2 weeks; Beck Depression Inventory (BDI; Beck et al, 1974), including 21 items, total score range 0-63.
Assessor-ratings were of: Hamilton Anxiety Scale (HAS; Hamilton, 1959), score range 0-56 and Clinical Global Impression (CGI) scale modified (Guy, 1976): illness severity, score range 0-8 (0=not ill; 8=extremely ill).
Statistics
Multivariate analyses of variance (MANOVAs) compared the four treatment
groups on the main outcome measures repeated on five occasions (weeks 0, 6,
10, 36, 62). Analysis of treatment group x time and its interactions
tested for significant differences among the three self-exposure groups (E, I
and E+I) and the control group across weeks 0-10. The three self-exposure
groups were also compared with one another on the main outcome measures from
weeks 0-62. 2 tests for non-parametric and analysis of
variance (ANOVA) for parametric data compared groups E, I and E+I on clinical
and demographic features at baseline.
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RESULTS |
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Baseline features
The 70 patients included in the study resembled those in other
panic/agoraphobia studies. Fifty-one (64%) were women. Mean age was 37 (s.d.
11), mean onset age 29 (s.d. 10), and mean illness duration 7 years (s.d. 8).
Most were in a stable relationship (67%), 83% were Caucasian and 67% had
completed college or university. All had panic disorder with agoraphobia: mean
assessor-rated phobic target avoidance was 13 (s.d. 2.8, range 0-16) and FQAg
was 21 (s.d. 11, range 0-40). Mean BDI scores were 20 (s.d. 10, range 0-63).
Thirty-four patients had comorbid symptoms: depression (17%), general anxiety
(17%), social phobia (6%), specific phobia (4%) and mixed (5%) at baseline.
Most (67%) had had past psychiatric treatment, mainly for panic/agoraphobia
(58%). Half had had antidepressants or benzodiazepines and 33% psychodynamic
psychotherapy. Of the 70 patients who began treatment, eight (11%) were on
antidepressants, 17 (24%) on benzodiazepines and 5 (7%) on both. Demographic
and clinical data did not differ significantly among the four treatment groups
on 2 tests.
Reliability of measures
At week 0, two assessors rated the first 20 patients independently in the
same interview on phobic avoidance, fear, and work/social adjustment to check
reliability. Pearson and intraclass correlation between the two assessors'
ratings were respectively 0.82-0.95 (P<0.001) and 0.94-0.98
(P<0.0001). Self v. assessor reliability was tested at
weeks 0 and 10. Pearson correlations for the three measures were highly
significant (P<0.0001) at weeks 0 (0.68-0.77) and 10 (0.80-0.85).
Intraclass correlations were highly significant (0.54-0.96;
P<0.001) for all measures at week 0, at week 10 they were highly
significant (0.55-0.84; P<0.001) for phobic avoidance and fear,
less so for social adjustment (0.50; P<0.05).
Improvement during treatment
Table 1 shows means (s.d.)
of the averaged self- and assessor-ratings for phobic target avoidance, phobic
target fear and work/social adjustment and the other outcome measures for the
three self-exposure groups and the control group, and
Fig. 1 shows means of those
four groups at weeks 0, 6, 10, 24, 36 and 62 on target avoidance, the HAS, CGI
scale and Agoraphobic Cognitions Scale. Groups E, I or E+I (total
n=62) each improved significantly (P<0.001) and similarly
(P n.s. on between-group comparisons) and significantly
(P<0.001) more than control group patients (n=18) on all
10 outcome measures from weeks 0-10. Effect sizes for the three self-exposure
groups were all large in comparison to the control group at post-treatment on
phobic target avoidance (E 2.5; I 3; E+I 1.6). The three self-exposure groups
were pooled and a percentage of clinical improvement was calculated by
subtracting week 0 from week 10 scores and dividing by week 0 scores on the
main measures. At week 10 this was 74% for phobic target avoidance and 41% for
the CGI scale.
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Follow-up results
Fifty-two patients were followed up from weeks 10-62. During this time most
kept their gains or improved further (Fig.
1). The three self-exposure groups did not differ significantly
from one another on the main outcome measures from weeks 0-62. Effect sizes
increased at 1 year follow-up for groups E, I and E+I, on phobic target
avoidance (E 4.7; I 3.5; E+I 3.8), CGI (E 4.1; I 3.3; E+I 4.3) and HAS (E 2.8;
I 3.5; E+I 3.4). Clinical improvements additional to those at post-treatment
were 17% for phobic target avoidance and 16% for CGI. Eight (2 in E; 2 in I; 4
in E+I) of 52 patients had 1 or 2 booster sessions for anxiety during
follow-up.
Assessor blindness
Patients were asked not to tell the assessor anything about their treatment
and homework tasks. At week 10 the assessor was asked to guess the patient's
treatment condition. Correctness of guesses was 30%, a rate to be expected by
chance.
Refusers, drop-outs and non-completers
Twenty patients (9 in E; 2 in I; 7 in E+I; 2 in control group) left the
trial before week 4 and were replaced. Of the 18 control group patients
assessed at week 10, eight did not return for subsequent self-exposure
treatment, four developed depression and had to be referred to pharmacotherapy
and four sought treatment elsewhere. Among the three self-exposure groups,
five patients (2 in E; 2 in I; 1 in E+I) dropped out between weeks 6 and 10
and another five (1 in E; 2 in I; 2 in E+I) between weeks 10 and 62 - a low
total drop-out rate of 12% (3 in E; 3 in I; 4 in E+I). Drop-outs were mainly
because of the inconvenience of attending, lack of improvement or
depression.
Concurrent use of medication
Thirteen patients were on either antidepressants, benzodiazepines or both
at baseline. Five patients were in the control group and three of those were
reallocated to the self-exposure groups (n=11: 3 in E, 6 in I, 2 in
E+I). Patients who were on antidepressants and those who were not did not
differ significantly on t-tests.
Intent-to-treat analyses
This was done for the 90 patients randomised in the trial to test for
differences between the four treatment groups regarding improvement from weeks
0 to 10 and weeks 10 to 62. Patients who dropped out before week 4 (20
refusers: 9 in E; 2 in I; 7 in E+I; 2 in control group) and between weeks 6
and 10 (five drop-outs) were considered non-successes. Completers who improved
by at least 30% on the CGI scale at week 10 were rated as successes (12 in E;
1 in I; 11 in E+I). The three treatment conditions did not differ
significantly on 2 tests regarding drop-out and
success/non-success rates to week 10 or 62.
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DISCUSSION |
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The three self-exposure treatments reduced panic and agoraphobia equally well through weeks 10-62. Although control group patients had no meetings with therapists that might give an attention-placebo effect, the three self-exposure groups' similar improvements in agoraphobia were unlikely to be due to an attention-placebo effect, as other panic/agoraphobia studies found little change following attention given with reassurance (Swinson et al, 1992), relaxation (Marks et al, 1993), or anti-exposure instructions (Telch et al, 1985). In one study, teaching a control group relaxation techniques (relaxation-placebo) improved panics but not agoraphobia (Marks et al, 1993).
Perhaps reducing differing elements of the fear network led to similar knock-on improvements in other elements, with the lessening of fear of external cues also lowering fear of internal cues and vice versa. A further possibility is that group I patients improved from the breathing retraining that was present in groups I and E+I but not in group E; this requires further study by giving interoceptive exposure without breathing retraining. Group I had fewer refusals than either groups E or E+I between weeks 0 and 4, which might be due to a smaller rise of anxiety in group I early in treatment (Foa et al, 1983).
Patients in all three self-exposure groups were told briefly that panic and anxiety are not harmful. Shear et al (1994) found no difference between exposure (external and interoceptive cues) plus cognitive restructuring plus breathing retraining plus relaxation v. a non-prescriptive programme that educated patients about the harmlessness of panic. This alone might reduce panic. Perhaps group I patients learned to cope with panic symptoms, so encouraging them to do E-type homework, but this was not measured in the study. No anti-exposure instructions were given to group I patients that might have stopped them from doing self-exposure to external cues. The role of group E exposure homework deserves more investigation in future research.
A non-significant trend favoured group E+I conditions at post-treatment and at follow-up. Was our sample size too small to detect significant but subtle differences in treatment effects between groups? If so, the clinical meaningfulness of such differences is debatable. Comparisons between exposure and non-exposure groups of patients commonly yield significant differences with cell sizes of merely five, whereas our cell sizes were over thrice that.
Most of the present patients had panic disorder with agoraphobia. It is worth testing whether group I conditions would produce even more improvement in panic disorder without agoraphobia.
Of present patients, 69% were self-referrals. The sample as a whole was severely disturbed on initial main phobic target, FQAg and total phobia (FQT) scores, and moderately depressed on the BDI (as much as mainly doctor-referred patients at I.M.'s unit in London). Their posttreatment improvement, too, resembled that usually obtained in the unit. It would be hard to invoke undetected differences in self- v. doctor-referred patients as explaining the absence of differences between groups, E, I and E+I.
In conclusion, self-exposure to external or to interoceptive cues each improved panic disorder plus agoraphobia significantly and similarly up to 1 year after treatment ended, and each was better than a 10-week waiting-list control condition. Combining the two forms of exposure was not synergistic.
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Clinical Implications and Limitations |
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LIMITATIONS
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REFERENCES |
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Received for publication March 2, 2000. Revision received July 24, 2000. Accepted for publication August 14, 2000.