Mixed anxiety–depression in a 1 year follow-up study: shift to other diagnoses or remission?

TL;DR: While depressive disorders and anxiety disorders showed relatively high stability, MAD cannot be seen as a stable diagnosis: most of MAD patients remit; many of them shift to other diagnoses than depression or anxiety.

About: This article is published in Journal of Affective Disorders.The article was published on 2004-04-01 and is currently open access. It has received 47 citations till now. The article focuses on the topics: Anxiety disorder & Anxiety.

Summary

1. Introduction

• A substantial number of patients suffer from depressive and anxiety symptoms without meeting official criteria of either ICD-10 or DSM-IV depressive and/or anxiety disorders (Zinbarg et al., 1994; Stein et al., 1995; see Katon and Roy-Byrne, 1991; Wittchen and Essau, 1993; Boulenger et al., 1997 for reviews).
• To provide a clinical definition for those patients the ICD-10 (WHO, 1992) introduced the concept of mixed anxiety–depression disorder (MAD).
• The status of the ICD-10-MAD diagnosis — in relation to depressive and anxiety disorders — needs further research.
• Data were collected within the scope of the World Health Organization (WHO) Collaborative Study on ‘Psychological Problems in General Health Care’, which is a cross-sectional and prospectivelongitudinal international study (Sartorius et al., 1993; Üstün and Sartorius, 1995).

2. Methods

• From the sample of the WHO Collaborative Study1 patients meeting ICD-10 criteria for a depressive episode, dysthymia, agoraphobia, panic disorder, generalised anxiety disorder (GAD), comorbid depressive and anxiety disorder, and MAD at the baseline assessment were identified and reassessed after 12 months.
• Patients older than 65 years were excluded.
• ICD-10 diagnoses were obtained using the Composite International Diagnostic Interview- Primary Health Care Version (CIDI-PHC), a modification of the Composite International Diagnostic Interview (CIDI; Division of Mental Health, 1990).
• The interviewer–observer reliability coefficient (across different centres) of the CIDI-PHC was 0.92 overall, ranging between 0.81 to 1.0 on the item level.
• Single comparisons within the whole contingency table were carried out (Jesdinsky, 1968).

3.1. Sample characteristics

• A total of 1856 patients were identified to meet ICD- 10 criteria for a depressive episode, dysthymia, agoraphobia, panic disorder, GAD, comorbid anxiety and depressive disorder, and MAD at the baseline diagnostic assessment.
• A total of 673 (36.3%) did not participate in the follow-up examination because they had moved and were not found anymore, because of refusal or because of death.
• The study sample of the baseline assessment is described in Table 1.

3.2. Twelve month outcome

• MAD, depressive episodes, dysthymia, agoraphobia, panic disorder only, GAD, and comorbid depressive and anxiety disorder showed a substantial improvement (average remission rate: 41.9%).
• 7% of all patients had exactly the same ICD- 10-diagnosis at both assessments with MAD showing the lowest rate of stable diagnoses (1.2%).
• The majority of MAD patients remitted or shifted to other (non-depressive and non-anxiety) diagnoses (see Table 2).
• There were no differences regarding follow-up depression rates between patients with a depressive disorder and comorbid patients [χ2 = 0.01, df =1, not significant (n.s.)] and no significant differences regarding follow-up anxiety rates between patients with an anxiety disorder and comorbid patients at baseline (χ2 = 0.9065, df =1, n.s.).

4. Discussion

• The data presented herein did not show temporal stability of MAD as compared to depressive and anxiety disorders.
• The authors results are in contrast to the findings of Usall and Marquez (1999) who concluded that MAD is a stable diagnosis.
• These authors applied DSM-IV research criteria so that their results cannot be directly compared with their findings.

4.1. Implications

• ICD-10 MAD criteria are relatively vague compared to DSM-IV research criteria (APA, 1994) clearly specifying symptoms necessary for the MAD diagnosis.
• For such a revision several possibilities are conceivable: Preskorn and Fast (1993) argue against a MAD diagnosis and are in favour of a careful psychiatric assessment resulting in either depression or anxiety diagnoses.
• Either way, the present study shows that an assiduous psychiatric assessment incorporating longitudinal information (i.e., medical history and follow-up assessments) is indispensable.
• Of course, the question arises whether the ICD-10 classification lives up to rather minor disorders frequently seen in primary care and whether an appropriate ICD-10 diagnosis suffices.
• Especially in minor disorders, where psychotherapeutical approaches play an important role, the formulation of an individual disease model and an according treatment is much more determining.

4.2. Limitations

• Depressive and anxiety disorders might be more severe disorders than MAD, therefore, more easily remitting.
• Nevertheless, the remission rates for the other disorders were also quite high.
• Moreover, GAD which also can be seen as relatively mild psychiatric condition shows a high degree of chronicity (Mancuso et al., 1993; Schweizer, 1995; Woodman et al., 1999).
• In older patients with longer illness histories a MAD diagnosis might not be so easily corrected.
• Other limitations are lacking information regarding treatment and remissions and relapses during the follow-up.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Mixed anxiety–depression in a 1 year follow-up study: shift to other diagnoses or remission?" ?

In 1992, the ICD-10 introduced the concept of mixed anxiety–depression disorder ( MAD ). However, a study examining the stability of this ICD-10-diagnosis is lacking. Limitations: Detailed information regarding treatment and disorders during the follow-up interval was lacking.