To assess the effectiveness of treatments for panic disorder on long-term outcomes.

MEDLINE and PsycLIT were searched from 1980 onwards using the headings of 'panic disorder', 'anxiety neurosis', 'agoraphobia' and 'anxiety disorder' cross-referenced with 'outcome' and 'follow-up'. Additional material was obtained by examining references from retrieved articles, and by handsearching relevant literature.

Study designs of evaluations included in the review

All studies examining outcomes of a particular treatment modality with follow-up of at least 6 months after treatment termination. Unpublished studies or studies published as letters were excluded.

Specific interventions included in the review

Drug treatment included alprazolam and imipramine. Behavioural treatment included behavioural group therapy, psychoeducation, relaxation techniques, cognitive restructuring, group exposure, desensitisation with graduated exposure homework, and assertiveness training.

Participants included in the review

Patients suffering from panic disorder. No other patient information is provided [A: as not available in the primary studies].

Outcomes assessed in the review

Continued need for treatment and long-term outcome of specific treatment interventions, including acute treatment, follow-up medication and psychotherapy.

How were decisions on the relevance of primary studies made?

[A:By two authors independently, with consensus by discussion].

Studies were assessed on four criteria:

the studies had to have used American Psychiatric Association DSM-III criteria for panic disorder with or without agoraphobia or agoraphobia with panic attacks, or DSM-III-R criteria for panic disorder with or without agoraphobia;

the studies had to provide well-described treatments that were administered in as standard a manner as possible, with therapists adequately skilled in the administration of treatment;

the experimental treatment (which can be a combined-modality treatment) was the sole treatment being administered during the study period; and

during the follow-up interval, it had to be indicated whether additional treatments for panic were being used by the patients.

If an intervening treatment was sought out or required by patients during the follow-up interval, this information needed to be closely tracked, as it contains important implications about the long-term efficacy of the experimental treatment. [A:By two authors independently, with consensus by discussion].

[A:By two authors independently, with consensus by discussion].

How were the studies combined?

A narrative synthesis was undertaken.

How were differences between studies investigated?

Differences between the studies were investigated by subgroup analysis using the validity criteria.

Thirty-one studies were identified although only 5 studies of four patient populations (279 patients) met the criteria that make a long-term outcome study useful in providing information about differential treatment efficacy.

The quality of the studies was analysed. Methodological problems were found among the majority of studies; these included lack of clarity of diagnosis, lack of clarity in the treatment administered, and inadequately tracked non-study treatments during the study and follow-up periods.

Evidence from the four studies adhering to the quality criteria of the study indicate that although a majority of patients are responsive to treatment, many patients continue to experience symptoms and/or require ongoing treatment interventions.

There is limited evidence for the long-term maintenance of short-term treatment gains in panic disorder patients in the absence of continued treatment.

The review adequately defined its objectives, literature search, inclusion and exclusion criteria, and validity criteria. In contrast, the review lacked sufficient description of patient characteristics, treatments and outcomes, and the process by which decisions of relevance, judgements of validity and data extraction were undertaken. Details of the primary studies were inadequate [A:due to the lack of information provided in the primary studies]. Methodologically, the primary studies were of poor quality, rendering any conclusions tentative and preventing achievement of the objective of the review.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.