DSM-5 Criteria and Depression Severity: Implications for Clinical Practice

Abstract

Background: Depression diagnosis requires five or more symptoms (Diagnostic and Statistical Manual of Mental Disorders-DSM-5). One of them must be either Depressed mood or Anhedonia, named main criteria. Although the secondary symptoms can be divided into somatic and non-somatic clusters, the DSM-5 identify depression in all or none fashion. In contrast, depression severity is a continuous variable. Therefore, it is commonly assessed with scales such as the Hamilton Depression Rating Scale (HAMD). Previously, we reported that patients with moderate depression (MD) exhibit greater impairments in cardiac-autonomic modulation than severely depressed (SD) patients. However, clinicians usually do not use scales. Objective: To verify whether the DSM-5 symptoms would be able to discriminate SD from MD and MD from non-depressed (ND) subjects. Material and Methods: Depression was diagnosed based on the Structured Clinical Interview for DSM-5® Disorders. The HAMD evaluated depression severity. In depressed subjects, MD and SD were defined considering the HAMD scores. ND was defined considering both the absence of DSM-5 criteria for depression and the HAMD score. Among 782 outpatients, 46 SD were found. MD and ND subjects were randomly sampled to match the demographic variables of the SD group. Results: Discriminant analysis showed that Depressed Mood was the most reliable symptom to discriminate ND from MD. Anhedonia discriminated SD from MD. Among the secondary DSM-5 criteria, the somatic cluster discriminated ND from MD and the non-somatic cluster SD from MD patients. Discussion: The presence of the somatic cluster in MD may indicate decreased vagal tone and/or increased sympathetic tone, leading to higher cardiovascular risk. As SD is associated with the non-somatic cluster, these patients are at risk of committing suicide. The DSM-5 symptoms exhibited by the patient may help the choice of adequate pharmacological treatment. This would avoid the use of antidepressants that unnecessarily increase cardiac risk in MD. When the symptom cluster suggests SD, the treatment must focus on the prevention of suicide. Conclusions: Depression severity may be inferred based on the DSM-5 criteria. The presence of the Anhedonia main criterium accompanied by non-somatic criteria indicate SD. The Depressive Mood criterium followed by somatic criteria suggest MD.

Keywords: autonomic nervous system; cardiac arrhythmias; cardiovascular system; depression; sudden death; suicide.

Figure 1

Design of the study (timeline). The initial sample consisted of 904 outpatients. After applying the exclusion criteria, 782 eligible patients were recruited to participate in first part of this study. Based on the DSM-5 criteria, 189 patients exhibited a major depressive episode at the time of the Structured Clinical Interview for DSM-5® Disorders-Clinician Version. The Hamilton Depression Rating Scale (HAMD) were administered in the depressed outpatients and the non-depressed group (n = 593). Based on the HAMD cut-off scores, three groups were selected: Non-depressed (ND), Moderately Depressed (MD), and Severely Depressed (SD). After the analysis of the HAMD scores (n = 782), 46 severely depressed patients were found. Age, percentage of females, years of education, and mini-mental state exam scores were calculated for the SD group. These demographic values were used to sample the other two groups (ND and MD). Then, from the total number of subjects in the other two groups (ND and MD), 92 subjects (46 MD and 46 ND) were randomly selected to be included in the analyses.

Figure 2

Summary of the results. Depressed mood is the most reliable DSM-5 symptom to discriminate moderately depressed (MD) group from non-depressed (ND) group. Loss of interest or pleasure discriminates severely depressed (SD) group from MD. Considering the secondary DSM-5 criteria, the somatic items discriminate MD from ND groups. All the non-somatic DSM-5 criteria separate MD from SD groups. The ellipses represent the non-somatic DSM-5 items and the rectangles the somatic DSM-5 items, according to the factor structure described by Elhai et al. (10). DM, depressed mood; LI, loss of interest or pleasure; SD, sleep difficulties (insomnia or hypersomnia); C, diminished ability to think or concentrate; FE, fatigue or loss of energy; FW, feelings of worthlessness or excessive guilt; SU, suicidality; AW, appetite or weight disturbance; PAR, psychomotor agitation or retardation.