About 25 percent of prostate cancer (PCa) patients experience significant depression as a result of their illness, its diagnosis, or its treatment [1
]. As well as emotional distress, depressed PCa patients also have significantly greater chances of admission to emergency treatment, hospitalization, outpatient visits and death [4
]. Therefore, the ongoing investigation of the causes of depression among PCa patients and the efficacy of interventions aimed at reducing the intensity of that depression is clearly justified. Underlying that research is an understanding of the nature and structure of depression as it is experienced by this patient group, particularly as regards one of the major forms of depression---melancholic depression [5
], which may have implications for both assessment and treatment of depression in PCa patients [6
Although the first records of the term "melancholia" date from the ancient Greeks (from melas
(meaning black) and khole
(bile)), it was used by Hippocrates (Aphorisms
, section 6.23) to describe what is nowadays referred to as "general depression": "If a fright or despondency lasts for a long time, it is a melancholic affliction"
, rather than the subset of depressive symptoms which are grouped under the modern term "melancholia". Melancholia was also used during the Middle Ages by Avicenna, in his Canon of Medicine
, who described it as a depressive mood disorder which was also called "acedia", meaning an absence of caring
, much like anhedonia in modern definitions of depression
. In the fifteenth century, Robert Burton [9, p. 32] reported melancholy, its causes, symptoms and remedies in great detail, describing a typical sufferer as "we call him melancholy, that is dull, sad, sour, lumpish, ill-disposed, solitary, any way moved, or displeased". Samuel Johnson, in his description of Rasselas, Prince of Abisinnia
, referred to "melancholy" as containing a strong dose of unwarranted guilt, thereby linking the disorder with those who were prone to superstition. During the 18th
century, this focus upon the personality characteristics of those who suffered from melancholy was replaced by an emphasis upon more physiological bases, principally low energy and slowed circulation
, and the modern term "depression" was eventually used in place of melancholia. The latter term was then adopted to describe a particular subset of depressive symptoms.
Melancholic patients have been characterised as suffering from extreme and persistent anhedonia, plus psychomotor retardation or agitation, excessive guilt or hopelessness, suicidal features, and appetite disturbances or weight changes, all of which distinguish patients with melancholic depression from those with more general distress [6
]. Of interest, patients with predominantly melancholic symptoms are not necessarily more depressed than others, with at least 50% of people who score in the upper half of the severity range for depression not showing the symptoms of melancholia [14
]. These behavioural symptoms of melancholia have biological substrates that contribute to them, including dysfunction of the hypothalamic-pituitary-adrenal axis (which influences emotions and the sympathetic nervous system and may produce guilt and hopelessness [15
]), the thyroid axis (which may contribute to psychomotor abnormalities, weight loss and sleep disturbances [16
]), rapid eye movement patterns during sleep (which may be a result of altered circadian rhythms and thus contribute to sleep disturbances [17
]), and left dorsolateral prefrontal cortex activity (which is linked with mood disorders [18
These concomitant biological factors which may occur before or alongside the psychological symptoms of depression may be potentially compounded by the physiological symptoms of cancer in general (or its treatment), leading some researchers to opt for the use of scales which omit somatic symptoms (e.g., the Hospital Anxiety and Depression Scale). For example, one study which used the same depression-screening scale as was used in the present study reported a factor structure for that scale which broke total scores into cognitive, depressed mood, and two somatic components among a sample of 1,109 patients with a range of cancers (although PCa was not mentioned in the sample description)
, suggesting that the "neurovegetative symptoms of depression were separable from the cognitive/ideational symptoms, with the latter being more reliable for diagnostic purposes" (p. 126), and that some somatic symptoms might be attributable to cancer and its treatment as much as to depression. However, another study with a mixed cancer sample (5% of the sample were PCa patients) and which used an abbreviated form of the same depression-screening scale found that this (somatic item-free) abbreviated scale correlated .91 with the entire (somatic item-inclusive) scale
, thus challenging the argument that all somatic items need to be excluded from assessment of depression among cancer patients.
While there is some validity in the argument proposed regarding deletion of somatic items from depression screening of mixed cancer patients due to the potential range of cancer-related physiological symptoms which might be confounded with depression symptomatology, the specific cancer-related symptoms that have been reported in PCa patients narrows the range of somatic symptoms that may need to be excluded. For example, several major reviews of specific PCa-related symptoms refer to: incontinence and impotence, problems with urinary control, sexual and bowel function
, tumor flare, hot flashes, and gynecomastia where antiandrogens are used
. Radiation-induced proctitis and bleeding have also been reported in PCa patients
. While these can cause significant discomfort, and may lead to some of the behavioural symptoms of melancholia listed at the commencement of this paragraph, they do not readily overlap with the somatic symptoms of depression as defined via the DSM-IV-TR, and it may be that scales which screen for depression and which include somatic symptoms can be delivered with some degree of confidence as long as the depression symptoms assessed are not those reported (above) that arise from PCa itself or its treatment.
Some data suggest that depressed persons who exhibit melancholic features are more likely to attempt violent suicide [24
], although that outcome may be more related to some of the specific symptoms of melancholic depression such as guilty feelings, anhedonia and loss of interest rather than the complete group of symptoms that comprise melancholia [25
]. In either case, the increased likelihood of suicide in PCa patients who exhibit melancholic features of depression lends urgency to investigations of the presence of melancholia among this patient group. As an additional impetus to such investigations, there is a longstanding clinical belief that patients with melancholic depression respond better to pharmacological treatments than to psychotherapy [26
], presumably because of the powerful biological underpinnings to their depression. However, that position has been challenged as being more likely related to the biological correlates of melancholic depression rather than the psychological/behavioural symptomatology itself [17
Despite the importance of understanding the extent of melancholia among depressed PCa patients, and how this might inform choice of treatments for those PCa patients whose depression exhibits melancholic features, a search of Google Scholar, PubMed and Science Direct in August, 2011, using the descriptors "prostate cancer, melancholic depression", failed to identify any study which had examined this issue within the PCa population. Therefore, the present study was designed to investigate the incidence of melancholic depression among a sample of PCa patients (using Frequencies analysis in SPSS), whether melancholic or nonmelancholic symptom clusters were stronger predictors of overall depressive status (using Linear Regression), whether melancholic symptomatology was more common or more intense among PCa patients who had severe depression than those with less severe depression (via MANOVA), and also to explore the structure of melancholic depression in a sample of PCa patients (via Factor Analysis), with a view to informing treatment recommendations for this patient group. Because of the exploratory nature of this study, a priori power analyses were not conducted, and post hoc examination of reported B values was done instead.