What is depression? How does it affect cancer patients?

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A common emotional state that can be conceptualized along a continuum ranging from transient, nonclinical periods of low mood and sadness that remit quickly on their own, to a serious, life-threatening, clinical disorder requiring aggressive psychiatric intervention. Depression can lead to significant impairment in an individual’s ability to function and is a leading cause of disability worldwide.
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Risk factors: Depression is most common among cancer patients with advanced disease and with symptoms and discomfort that are not treated or inadequately treated. It commonly coexists with anxiety and is common in individuals with substance abuse problems and other chronic physical and mental disorders. Most cancer patients manifest transient symptoms of depression that are responsive to support, reassurance, and information about what to expect regarding the course, treatment, and prognosis of their disease. Others experience unremitting or recurrent depression requiring aggressive monitoring and intervention. The following list depicts risk factors that favor the development of clinically significant depression within the context of a cancer diagnosis:

  • Family history of depression
  • Past history of depression, depression treatment, psychiatric hospitalization, or significant psychiatric/personality disorder
  • History of unusual, eccentric behavior
  • Confusion (may be indicative of an organically based depression)
  • Maladaptive coping style
  • Dysfunctional family coping or complex family issues
  • Limited social support
  • Financial problems including lack of insurance
  • Multiple roles, obligations, and stressors
  • Advanced cancer
  • Treatment resulting in disfigurement or loss of function
  • Presence of dependent children
  • Inadequate symptoms management
  • Treatment that has a depressionogenic effect (certain chemotherapies, steroids, narcotics)

Etiology and the disease process: Simplistically stated, the etiology of clinical depression, cancer related or not, is based on a complex interaction of factors. These include genetic predisposition to aberrant neurochemical states that precede or result from an inadequate stress response combined with a distorted, negatively biased cognitive style or worldview that is learned and reinforced early in life. This multidimensional framework indicates need for a combined psychopharmacologic and psychotherapeutic treatment approach that is well supported in the medical literature. Clinical depression can present as a single episode, be chronic and unremitting, or occur over time with periods of remissions and exacerbations.

A crisis framework is often used to describe the occurrence of depression in the context of cancer. The acute crisis response (ACR) typically occurs at transitions in the disease trajectory (diagnosis, treatment initiation, recurrence, treatment failure, disease progression). The ACR is characterized by symptoms of anxiety and depression that usually resolve within a short time period. Time frames are variable, but the ACR usually resolves when individuals know what to expect in terms of treatment, receive reassurance that discomfort can be controlled, and mobilize usual coping strategies and support systems. When symptoms worsen rather than resolve over time or coping mechanisms are insufficient, treatment for depression must be considered regardless of whether diagnostic criteria for a clinical diagnosis are met.

Incidence: Prevelance rates vary and depend on the population studied, site and stage of disease, and method used to measure depression. Prevalence rates among cancer patients range from 5 percent (lower than general population rates) to 90 percent. In general, studies that use established diagnostic criteria report rates of depression of about 25 percent. Rates of depression are highest among patients with advanced cancer and in studies in which stringent diagnostic guidelines are not used.

Symptoms: Symptoms of depression in cancer populations include the following:

  • Persistent sad mood
  • Loss of interest or pleasure in typically pleasurable activities
  • Feelings of guilt, worthlessness, helplessness
  • Crying, not easily comforted
  • Frequent thoughts of death or suicide
  • Trouble concentrating, indecisiveness
  • Appetite change
  • Diminished energy that may be mixed with restlessness and anxiety
  • Fatigue, loss of energy
  • Insomnia or hypersomnia

Diagnosis of cancer-related depression relies heavily on the presence of affective symptoms (the first five symptoms in the list). Neurovegetative symptoms (the last five symptoms in the list) that characterize depression in physically healthy individuals are not good predictors of depression in cancer patients because cancer and its treatment produce similar symptoms. Additional behaviors suggestive of depression include refusal, indecisiveness, or noncompliance with treatment; persistent anxiety and sadness, unresponsive to usual support; unremitting fear associated with procedures; excessive crying, hopelessness that does not diminish over time; an abrupt change in mood or behavior; eccentric behavior or confusion; and excessive guilt or self-blame for illness.

Screening and diagnosis: A formal diagnosis of depression is based on fulfillment of criteria outlined in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM). The diagnostic subtypes of depression include major depressive disorder (severe depression that lasts for more than two weeks and is particularly amenable to pharmacologic treatment), adjustment disorder with depressed features (depression that occurs in response to a clearly defined event or stressor), dysthymia (chronic, low-level depression that pervades an individual’s personality and daily life), and bipolar disorder (a genetically determined severe form of depression that may or may not alternate between depressive lows and manic highs and is responsive to mood-stabilizing, pharmacologic agents). Major depression and adjustment disorder are common diagnoses among individuals with cancer. Dysthymia and bipolar disorder usually precede a cancer diagnosis or occur for the first time following cancer diagnosis in those genetically predisposed.

Depressive symptoms not severe enough or of sufficient duration to achieve diagnostic status are the most common type of depressive phenomena in individuals with cancer. Because a formal diagnosis is not present, these symptoms are often ignored despite a common, negative impact. More research on the simultaneous occurrence of cancer and depression is needed, including symptom profiles, clinical treatment trials, and related outcomes.

A number of tests screen for depression, but they have not been consistently incorporated into clinical care. Nonpsychiatric providers fail to diagnose and treat depression in as many as 50 percent of cancer patients with depressive disorders. Obstacles to recognizing depression include inadequate provider knowledge of diagnostic criteria, competing treatment priorities in oncology settings, time limitations in busy offices, concern about the stigma associated with a psychiatric diagnosis, limited reimbursement, and uncertainty about the value of screening mechanisms for case identification. In general, regardless of whether screening measures are used, if symptoms do not remit in a reasonable time frame, evaluation of depressive symptoms by a psychiatric specialist should be sought.

Treatment and therapy: Psychosocial interventions can exert an important effect on the overall adjustment of patients and their families to cancer and its treatment. Factors contributing to the diagnosis of depression should influence the treatment approach. Treatments include psychopharmacologic treatment, individual psychotherapy, group therapy, family therapy, marital therapy, or some combination of these.

Antidepressant medication should be chosen on the basis of diagnostic subtype, treatment response, and side effect profile. Bipolar disorder is usually treated with a mood stabilizer, requiring careful monitoring and adjustment, especially during active treatment, as therapeutic blood levels are narrow and can shift dramatically in response to electrolyte and metabolic changes. Major depression is commonly treated with one of several classes of antidepressant medication, commonly a selective serotonin reuptake inhibitor (SSRI) or a a selective serotonin and norepinepherine reuptake inhibitor (SSNRI). Dosages are typically lower than required in healthy individuals and can positively affect other symptoms that the patient might be experiencing, such as pain and anxiety. In the oncology setting, a multimodal treatment approach is most effective in treating depression and can have a positive impact on a range of psychosocial and medical outcomes.

Prognosis, prevention, and outcomes: Left untreated, depression can produce a range of negative outcomes from diminished quality of life to noncompliance with treatment to diminished survival. Depression can be prevented in some individuals by providing preemptive counseling, education, support, and information about resources. Early recognition and treatment offer the best hope for rapid remission. Modern therapies are effective in treating depression even among cancer patients who are in progressive and terminal stages of illness. Treatment can vastly improve quality of life and diminish suffering; thus routine screening and treatment should be a universal aspect of comprehensive cancer care .


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