Depressive symptom profiles and severity patterns in outpatients with psychotic vs nonpsychotic major depression

Abstract

Background

Previous research suggests that patients with psychotic major depression (PMD) may differ from those with nonpsychotic major depression (NMD) not only in psychotic features but also in their depressive symptom presentation. The present study contrasted the rates and severity of depressive symptoms in outpatients diagnosed with PMD vs NMD.

Method

The sample consisted of 1112 patients diagnosed with major depression, of which 60 (5.3%) exhibited psychotic features. Depressive symptoms were assessed by trained diagnosticians at intake using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition and supplemented by severity items from the Schedule for Affective Disorders and Schizophrenia.

Results

Patients with PMD were more likely to endorse the presence of weight loss, insomnia, psychomotor agitation, indecisiveness, and suicidality compared with NMD patients. Furthermore, PMD patients showed higher levels of severity on several depressive symptoms, including depressed mood, appetite loss, insomnia, psychomotor disturbances (agitation and retardation), fatigue, worthlessness, guilt, cognitive disturbances (concentration and indecisiveness), hopelessness, and suicidal ideation. The presence of psychomotor disturbance, insomnia, indecisiveness, and suicidal ideation was predictive of diagnostic status even after controlling for the effects of demographic characteristics and other symptoms.

Conclusions

These findings are consistent with past research suggesting that PMD is characterized by a unique depressive symptom profile in addition to psychotic features and higher levels of overall depression severity. The identification of specific depressive symptoms in addition to delusions/hallucinations that can differentiate PMD vs NMD patients can aid in the early detection of the disorder. These investigations also provide insights into potential treatment targets for this high-risk population.

Introduction

In the current nomenclature of psychiatric diagnosis, psychotic major depression (PMD) is conceptualized as a subtype of unipolar depression that is defined by the presence of psychotic features (delusions or hallucinations) occurring in the context of a severe depressive episode [1]. Studies have shown that PMD is often associated with greater illness severity [2], impairment [3], comorbidity [4], and mortality [5] compared with nonpsychotic major depression (NMD). Furthermore, PMD patients tend to have higher rates of illness chronicity [3], relapse [6], and psychiatric hospitalization [4], as well as a poorer response to standard treatments for depression [7], [8]. These patients often require adjunctive treatment with antipsychotic medications or electroconvulsive therapy [9]. Given the problem of treatment resistance in PMD [10], improvements in the identification and treatment of these patients are of paramount importance.

Psychotic symptoms have been shown to be present in up to 19% of depressed individuals living in the community [11] and 25% of depressed patients in psychiatric hospitals [12]. Unfortunately, PMD can be difficult to identify because (a) psychotic features in mood disorders can be more subtle than those found in patients with primary psychotic disorders, (b) patients often underreport psychotic symptoms because of embarrassment or paranoia, (c) clinicians frequently fail to fully assess for the presence of psychotic symptoms in patients with mood disorders, and (d) PMD patients tend to have high rates of psychiatric comorbidity that can make differential diagnosis based on unstructured or brief clinical interviews problematic [13], [14], [15], [16]. Therefore, in addition to the presence of overt psychotic features, researchers have attempted to identify other clinical features that are associated with a PMD diagnosis.

Psychotic major depression was originally associated with “endogenous” or “melancholic” types of depression; however, these classifications have been found to be only partially or inconsistently applicable to PMD patients (eg, the absence of diurnal variation in PMD compared with melancholic depression) [16], [17]. A number of studies have reported that certain individual symptoms in PMD patients tend to be more prevalent or severe, including suicidality [18], psychomotor disturbance (agitation or retardation) [12], [19], insomnia [20], guilt [17], and cognitive impairment [21]. Psychotic major depression tends to be associated with greater overall depression severity compared with NMD; however, some studies have shown that differences between PMD and NMD patients exist in many cases even after controlling for the influence of other symptoms [13], [17]. For example, Parker et al [17] showed that PMD patients could be differentiated from NMD patients based on the absence of diurnal variation and the presence of severe psychomotor disturbance, constipation, and sustained and unvarying depressive thinking content after taking into account the influence of other symptoms. Nevertheless, differences observed between PMD and NMD patients tend to vary considerably based on sample characteristics and study methodologies [22].

Most of the literature on the symptoms that differentiate PMD vs NMD has been conducted exclusively in inpatient samples (eg, Lattuada et al [2] and Coryell et al [12]) or in samples composed of both inpatients and outpatients taken from specialty clinics (eg, Parker et al [17] and Thakur et al [18]). However, PMD patients presenting for treatment in general outpatient psychiatry settings may differ in their clinical characteristics or as a function of the treatment setting itself. Unfortunately, relatively little is known about the clinical presentation of PMD patients being treated in the community specifically. Moreover, previous research has often failed to systematically investigate the severity of depression symptoms in PMD patients in addition to their presence/absence.

In the current study, we compared the rates and severity of current depressive symptoms in PMD and NMD patients by examining a sample of treatment-seeking psychiatric outpatients. These data were collected as part of the Methods to Improve Diagnostic Assessment and Services project (N = 2500), which represents an integration of research methods into a community-based outpatient practice affiliated with an academic university [23]. Patients completed a comprehensive assessment battery during clinic intake that included a structured clinical interview administered by trained diagnosticians. The aim of the current study was to identify specific symptoms that can help clinicians identify PMD in depressed outpatients other than the nonspecific clinical markers of greater illness severity or the presence of overt psychotic symptoms. Patients with PMD and with NMD were compared on their rates of symptoms for a current major depressive episode as per the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) [1], as well as the severity of these and related psychiatric symptoms. Furthermore, we attempted to identify the depressive symptoms that best differentiated the diagnostic groups after controlling for demographic characteristics and other symptoms present. On the basis of previous research, we hypothesized that PMD outpatients would be differentiated from those with NMD by symptoms including suicidality, psychomotor disturbance, insomnia, guilt, and cognitive impairment.