Factors leading to Chronic Depression

Transcription

1 REVIEW ARTICLE Factors leading to Chronic Depression Gurvinder Pal Singh and B S Chavan Abstract : Chronic depression is a debilitating and often life-threatening disorder. Chronic depression is an episode of depression that persists for more than two years. Chronic depression represents an important public health concern in India. It is underrecognised and untreated because of lack of understanding about the various etiological factors responsible for this disorder. Being a multifactorial disorder, research data has demonstrated that prominent causative factors of this chronicity are environmental factors, individual factors, biological factors, biochemical and treatment variables. The present article is an attempt to understand the role of these factors in the causation of chronic depression. Key Words: Chronic depression, dysthymia INTRODUCTION Chronic depression is more common than thought earlier and poses a major public health problem. 1-3 Patient to be classified as having a chronic major depressive episode must fulfill full syndromal criteria for major depression continuously for a minimum of two years. 4 Dysthymia refers to mild insidious depression persisting for longer than 2 years. Double depression is the term applied to dysthymia with superimposed episodes of major depression. Depressive disorders have traditionally been perceived as acute and episodic condition. Over the last two decades, however, it has been increasingly recognized that many patients experience a long-term and chronic course of depression. Many depressive patients, untreated or inadequately treated, become chronic and prior chronicity predicts future chronicity. Chronic depression causes enormous impact on individual, family and society. 5 Little is known about the aetiology of chronic depression. An important gap still remains in our knowledge concerning the causes or factors leading to chronic depression. Prevalence of chronic depression Prevalence of chronic depression varies from 3% to 5% and accounts for 30-35% of all cases of depression. 6 Rates of chronicity for naturalistically treated depressive episodes reportedly range from 7% to 12% after 5 to 10 years of prospective follow-up. 1,7 Among inpatients with major depression, chronic depression persisting through decades of follow-up occur at a rate of 7% to 20%. Weisman and Myers 8 have found incidence of chronic depression in general population to be around 4.5%. Causes of chronic depression In the last decade it has become increasingly clear that the etiology of chronic depression is multifactorial one. Factors associated with chronicity in major depressive disorders have been studied by few workers Various factors that are known to contribute to chronic depression are: 1) Environmental Factors: Chronic depression can occur when the stress in a person s environment becomes overwhelming and persistent such as years of childhood abuse and neglect. Traumatic life events, lack of social 18

2 support, severe family conflicts, marital problems, and persistent financial stress play an etiological role in chronic depression. Experience of negative life situations may be more relevant during course of chronic depressive illness. Brown et al 11 showed that negative life events were common before recovery in chronic depression. Large number of workers has reported that chronic depressives do have a number of negative life events ) Individual Factors: Various individual factors are: a) Behaviour and thought process b) Biological and biochemical c) Comorbid disorders. a) Behaviour and thought process: Research has been carried out to understand whether cognitive process plays a role in the causation of chronic depression. However, there are few data examining whether the cognitive perspective applies to chronic depression. Riso et al 13 in a cross-sectional study compared 42 outpatients having chronic depression with 27 outpatients of nonchronic major depressive disorder and 24 never psychiatrically ill controls on the basis of various cognitive variables. These variables were dysfunctional attitudes, attributional style, a ruminative response style and maladaptive core beliefs. Chronically depressed patients were found to be more elevated on measures of cognitive variables than those with major depressive disorders without chronicity. Following behaviours and thought processes might place a depressed person at higher risk of becoming chronically depressed: i) Quick Fix: Depressed patients want instant gratification and have never ending search for instant cure. These patients move from therapist to therapist, from drug to drug, continually seeking most illusive quick fix and readymade solutions of their problems. Delayed or lack of response to antidepressants does not match their expectations. Only instant gratification is what these patients are programmed to expect. Such a gap between their expectations and response rate leads to further worsening in their depressive symptoms. ii) Intermittent therapies: It is a common observation that majority of depressed persons discontinue treatment after major symptoms of depression disappear. 14 Symptoms of depression reappear after discontinuation of drugs. These patients never complete 6-9 months of treatment and thus have higher chances of becoming chronic. Fear of dependence on antidepressants, cost of treatment, inadequate knowledge about the treatment process and many other sociocultural factors may lead to discontinuation of treatment. Over time, the prospects of cure become more and more dim and the chronic depression becomes worse. iii) Dysfunctional and maladaptive thinking: This is the most difficult and important cognitive process. In depression, a pattern of thought which is dysfunctional and maladaptive is known to cause depression and lead to frequent relapse and chronicity. These patterns of thoughts result in narrow perception of reality and prejudgment of people s behavior and situations in life. Decreased dysfunctional thinking in recovering depressed patents could reflect predominantly (a) reduced access to dysfunctional schemas or (b) increased metacognitive monitoring of dysfunctional schematic products. 15 It may be the result of learned and reactional responses in coping with various stresses. b) Biological and biochemical factors: i) Role of thyroid: Prevalence of subclinical hypothyroidism is much more than overt hypothyroidism 16. Depression in hypothyroidism is more than that in normal population. A review of studies of depression and thyroid disease found that 52% of refractory depressed patients show evidence of subclinical hypothyroidism. More so, patients with lower Free Thyroid Index (FTI) values 19

3 had severe depressive symptoms. Lower FTI values and higher TSH values were associated with poorer response in bipolar patients. Conversly, the combination of lower pretreatment TSH and higher pretreatment FTI is associated with marked and rapid remission. 38% depressed patients with baseline TSH values between 3.0 and 5.5µIU/ml had abnormal results on thyrotropin releasing hormone stimulation. When the TSH returns to the normal range, most symptoms will resolve. However, it has become apparent in clinical practice that depressive symptoms and anergia may persist despite correction of the hypothyroid state by replacement of thyroid hormone. ii) Chronic depression and structural brain changes: Treatment resistant chronically depressed middle-aged patients are more likely to show structural brain changes like frontal and striatral atrophy. Treatment resistant depression shows right superior, mediofrontal and striatal changes. Sheline et al 17 used magnetic resonance imaging in assessment of hippocampal structure in patients with chronic depression. Evidence of hippocampal atrophy was found in such patients. Postmortem observations support these brain imaging findings. 18 These patients also show hippocampal and rostral anterior cingulate changes reflecting focal biochemical tissue composition. c) Comorbid Disorders: Detection rates for chronic depression appear to be poor and if significantly delayed, the presence of comorbidity may exacerbate this problem further. Comorbid disorders like physical disorders, psychiatric disorders, alcohol and substance abuse, neurological disorders, endocrinal disorders, personality disorders, illness behaviour, chronic fatigue syndrome and somatoform disorder may make a person prone to chronic depression. 3,18 Akiskal et al 19 and Grunhaus 20 have reported that associated psychiatric or physical illness can play a part in maintaining chronicity. Cerebrovascular disease appears to play a role in the etiology of late onset dysthymic disorder. 21 Sanderson et al 22 have observed high comorbidity of anxiety disorders in a study of chronic depressives. High baseline levels of anxiety delay the onset of response to antidepressants in patients with chronic depression ) Treatment variables: Treatment variables play a significant role in the causation of chronic depression. These include treatment resistance, inadequate treatment both in dose and duration, untreated patients and inadequate instructions to the patient concerning antidepressant percent patients fail to respond to antidepressants despite adequate dose and duration. Poor treatment response is seen in 40-55% of patients. 24 Poor adherence to treatment among patients is a major problem 25. Poor adherence is often driven by prevailing stigma about depression and antidepressant drugs. Only about half of patients continue to take the drug after 5-6 months. 26 Various predictors of non response 27 are i) REM latency: Shortened REM latencies predict treatment resistance and thus make a patient more prone to chronic depression. ii) Family history of depression: Family history of depression predicts worse outcome. There are studies showing that a positive family history is associated with early onset depression and chronicity of depression. 28 Scott reported that chronic treatment resistant depressives showed a significantly greater family history of affective illness in first degree relatives than non chronic depressive patients. 29 iii) Number of previous episodes: Number of previous episodes also predict poor outcome. Longer duration of episodes prior to treatment cause chronic depression. There is an additive risk of developing chronic depression with each subsequent episode. The results of several studies indicate that patients with depression 20

4 consistently receive no or low levels of antidepressant therapy. 30 The more episodes of depression a patient has, the risk appears to increase arithmetically by another 8%. Both the length and number of episodes of depression are risk factors for a long term course. 4) Atypical depression, psychotic and anxious depression: Patients having atypical features of depression, psychotic or anxious depression are more likely to have chronic depression and thus poor response to treatment. 31 Dysthymia may be more related to neurotic temperament. Increased neuroticism has emerged to be single important factor in chronic depressives as reported by many workers. 9,12 CONCLUSION Chronic depression is a common disorder and is a matter of concern particularly for clinicians as it is mostly undiagnosed and untreated. Although the exact mechanism of chronicity is still not known, a number of individual, environmental, biological, biochemical and treatment variables are reported to be associated in its etiopathogenesis. These can be briefly summarized by the acronym CHRONIC as follows: C-comorbid disorders; H-Hypothyroidism (subclinical); R-Resistant to antidepressants; O- Organic brain changes; N- Negative (Persistent) Life situations; I-Illness related variables and C- cognitions. REFERENCES 1. Keller MB, Lavori PW, Mueller TI et al. Time to recovery, chronicity, and levels of psychopathology in Major Depression: a 5-year prospective follow-up of 431 subjects. Arch.Gen.Psychiatry 1992; 49: Lavori PW, Keller MB, Scheftner W, et al. Recurrence after recovery in unipolar MDD: an observational follow-up study of clinical predictors and somatic treatment as a mediating factor. Int J Meth Psychiatr Res 1994; 4: Kornstein SG. Chronic depression in woman. J Clin Psychiatry 2002; 63: American Psychiatric Association (APA). Diagnostic and Statistical manual of Mental Disorders-4th ed Washington, DC: APA; Pincus AH, Pettit RA. The societal costs of chronic Major depression. J Clin Psychiatry 2001;62 (suppl 6): Trivedi MH, Kleiber BA. Algorithm for the treatment of chronic depression, J clin Psychiatry 2001; 63 : Mueller TI, Keller MB, Leon et al. Recovery after five years of unremitting major depressive disorders. Arch Gen Psychiatry 1996;53: Weisman M.M. and Myers JK. Affective disorders in U.S. urban community. Arch Gen Psychiatry 1978; 35: Brown,G.V., Adler Z. and Bifulco A. Life events, difficulties and recovery from chronic depression. Br J Psychiatry 1988;152: Murphy G.E., Woodroff R.A., Herjanic M. et al. Variability of the clinical course of primary affective disorders. Arch Gen Psychiatry 1974; 30 : Akiskal H.S. Factor associated with incomplete recovery in primary depressive illness. J Clin Psychiatry 1982; 43: Scott J. Review article: chronic depression. Br J Psychiatry 1988; 153 : Moller HJ, Demyttenaere K, Sacchetti E, et al. Improving the chance of recovery from the short- and longterm consequences of depression. Int Clin Psychopharmacol 2003 ;18: Riso LP, du Toit PL, Blandino JA et al. Cognitive aspects of chronic depression. J Abnorm Psychology; 2003; 112: Sheppard LC, Teasdale JD. How does dysfunctional thinking decrease during recovery from major depression? J Abnorm Psychol ;113: Samuels MH. Subclinical thyroid disease in the elderly. Thyroid 1998; 8: Sheline Y, Wang P, Gado M, et al. Hippocampal atrophy in recurrent major depression. Proc Natl Acad Sci USA 1996; 93: Manji HK, Moore GJ, Chen G. Clinical and preclinical evidence for the neurotrophic effects of mood stabilizers: implications for the pathophysiology and treatment of manic-depressive illness. Biol Psychiatry 2000; 48: Akiskal H.S, Rosenthal R.H., Rosenthal T.L., et al. Differentiation of primary affective illness from 21

5 situational, symptomatic and secondary depression. Arch Gen Psychiatry 1979; 36: Grunhaus L. Clinical and psychological characteristics of simultaneous panic disorder and major depression. Am J Psychiatry : Devanand DP, Adorno E, Cheng J, et al. Late onset dysthymic disorder and major depression differ from early onset dysthymic disorder and major depression in elderly outpatients. J Affect Disord 2004;78: Sanderson W.C., Beck T.A. and Beck J. Syndrome comorbidity in patients with major depression or dysthymia: Prevalence and temporal relationship. Am J Psychiatry 1990;147: Russe JM, Koran LM, Rush J, et al. Effect of concurrent anxiety on response to sertraline and imipramine in patients with chronic depression. Depress Anxiety. 2001;13: Rush AJ, Thase ME. Strategies and tactics in the treatment of chronic depression. J Clin Psychiatry 1997; 58 (suppl.13): Crisp AH, Gelder MG, Rix S et al. Stigmatisation of people with mental illness. Br J Psychiatry 2000; 177: Katon W, Von Korff M, Lin E, et al. Stepped collaborative care for primary care patients with persistent symptoms of depression: a randomized trial. Arch Gen Psychiatry 1999; 56: Paykel ES. Epidemiology of refractory Depression.In: Nolen WA, Zohar J, Roose SP, et al.(eds). Refractory Depression: Current strategies and future directions. New York.NY: John Wiley and Son s 1994: Klein DN, Schatzberg AF, McCullough JP, et al. Age of onset in chronic major depression: relation to demographic and clinical variables, family history, and treatment response. J Affect Disorder 1999;55: Scott, J.; Barker W.A. and Ecteston D. The castle chronic depression study: Patient characteristics and factors associated with chronicity. Br J Psychiatry : Keller MB. Depression: a long-term illness. Br J Psychiatry 1994; 26: Liebowitz MR, Quitkin FM, Stewart JW, et al. Antidepressant specificity in atypical depression. Arch Gen Psychiatry 1988; 45: Gurvinder Pal Singh, Senior Lecturer B S Chavan, Professor & Head Department of Psychiatry, Govt. Medical College & Hospital, Chandigarh. Corresponding Address : Gurvinder Pal Singh 1202, Sector 32-B, Chandigarh. gpsluthra@rediffmail.com 22