Biology of depression pdf

Those at risk for depression are hypothesized to have characteristic ways of interpreting events and circumstances that are excessively pessimistic and self-critical, with perceptions of helplessness and hopelessness about changing or improving their situations. Such views lead to the exacerbation and maintenance of symptoms of dysphoria and futility, sometimes to the extent of major depressive episodes and suicidality.

Moreover, prospective studies have verified that those considered at risk because of characteristic negative thinking are indeed likely to develop depressive reactions Alloy et al.

The information-processing approach to cognitive vulnerability refers to dysfunctional cognitive processes, such as biases in attention and memory, and overgeneralized thinking style e. Such biases may result in selective attention to negative information and reduced access to positive memories, increasing the likelihood of dysphoric reactions to negative events. An interesting recent development in cognitive theories of depression is the study of the origins of depressogenic cognitive styles.

Studies have also shown that negative cognitions are associated with histories of child abuse and maltreatment e. Depressive disorders are known to be associated with considerable impairment in interpersonal functioning—marital discord, intimate partner violence, parenting difficulties, insecure attachment, and low social support, to mention several specific areas. The symptoms of depression may contribute to difficulties in close relationships.

Irritability, loss of energy and enjoyment, sensitivity to criticism, and pessimistic or even suicidal thoughts may initially elicit concern from others, but eventually they may seem burdensome, unreasonable, or even willful—sometimes eroding the support of spouses, friends, and family Coyne, A prominent issue in depression is marital discord.

Meta-analyses across multiple studies have indicated significant associations between depression and self-reported poor marital satisfaction Whisman, Rates of divorce and never-married status are elevated among those with depression e.

One informative study found that depression, compared with other disorders, is uniquely associated with marital dissatisfaction. Zlotnick et al. Longitudinal studies show that depression may result from marital difficulties Whisman and Bruce, Also, depression may cause marital difficulties.

Other studies also show bidirectional effects of depression and marital dissatisfaction Coyne, Thompson, and Palmer, ; Davila et al. Numerous studies have reported high levels of depression among survivors of abuse.

In a meta-analysis by Golding , the weighted mean rate for depression among survivors of partner violence was 47 percent.

A strong predictor of maternal depression in home visiting samples is a maternal history of trauma, especially a maternal history of child abuse, domestic violence, or both Boris et al. Several mechanisms are likely to underlie the association between depression and difficulties in intimate relationships, including maladaptive cognitions and attachment insecurities leading to dependency, distrust, excessive reassurance-seeking, and other behaviors that provoke conflict.

Depressed individuals commonly report histories of violence and marital disruption in their early lives, as well as poor quality of care and relationships with their own parents. As a result of their early family histories, for example, insecure attachment representations may develop that make them vulnerable both to development of depression Bifulco et al.

Individuals exposed to ineffective parental role models are also likely to fail to acquire the social problem-solving skills needed to resolve conflicts in close relationships. An additional pathway to discord is that depressed people tend to marry other people with psychological problems, thus increasing the chances of marital disharmony.

A review and meta-analysis of several studies of patients with mood disorders confirmed the significant likelihood that individuals with depressive disorders marry others with depression Mathews and Reus, Depressed women patients have also been found to have higher rates of marriage to men with antisocial and substance use disorders e. Research on nonpatient samples also shows spouse similarity for depressive disorders e. Parenting problems and conflicts between parents and children are commonly associated with depression.

Chapter 4 , on the effects of parental depression on children, details the nature, extent, and consequences of dysfunctional parenting. Despite the desire of most depressed parents to provide nurturing, consistent, and responsive parenting, many are significantly likely to be negative, critical, or withdrawn in their interactions with their children e. Notably, intergenerational patterns of parenting problems are evident, with depressed adults highly likely to report that they had difficulties with their own parents e.

Related findings have been reported in community samples, in which depressed individuals reported more negative views of their parents e. Andrews and Brown , for example, found that women who became clinically depressed following occurrence of major life events were more likely to report lack of adequate parental care or hostility from their mothers, compared with those who did not become depressed see also Brown and Harris, When dealing with vulnerable populations, it is important to consider that parenting style may differ by ethnicity as well as by views on what constitutes appropriate parenting and parenting values Pinderhughes et al.

Intergenerational conflict is common among immigrant parents Phinney, Ong, and Madden, Children tend to acculturate and learn new languages faster Kwak, This creates conflict in families and may contribute to parental depression or exacerbate difficulties related to parental depression. In addition to difficulties in intimate family relationships, depressed people and those at risk for depression report problems with social support.

They appear to have problems with the availability—or the perception of availability—of supportive relationships with others, including friends and associates. Perceived support helps to reduce depression and its likelihood of recurrence Sherbourne, Hays, and Wells, However, depression is associated with low levels of perceived support Burton, Stice, and Seeley, ; Dalgard et al.

Such perceptions may cause failure to seek help and support even if it does exist. Space prevents the elaboration of the many candidates for personality traits and habits that might constitute vulnerability to depression, but we mention two factors that have received considerable recent attention: neuroticism and ruminative response style. The construct of neuroticism has had a long history in psychology. Neuroticism is a higher order personality dimension, defined by negative emotionality and high reactivity to real and perceived stress.

Neuroticism is a powerful predictor of depressive episodes, according to a review by Enns and Cox ; see also Fanous et al. Although the level of neuroticism may decline with reductions in depressive symptoms, recent longitudinal studies have supported the idea that relatively higher levels of neuroticism persist independent of depressive states e.

It is suggested that neuroticism may be one of the genetically transmitted traits that predisposes an individual to both stressful life events and depression, and to tendencies to respond to stressors with depression Kendler et al. Kendler, Gardner, and Prescott , for example, found that neuroticism was a strong predictor of stressful life events, particularly those related to interpersonal relationships.

In other analyses, Kendler, Kuhn, and Prescott found that neuroticism moderated the effects of stress on depression, particularly potentiating its effects at the highest levels of stress exposure. Neuroticism is highly correlated with trait anxiety Watson and Clark, , harm avoidance Zuckerman and Cloninger, , and measures of the behavioral inhibition system. Watson and Clark suggested that these are interchangeable measures of the same stable and pervasive trait, which they label negative affectivity.

It is defined as the disposition to experience aversive emotional states, including nervousness, tension, worry, anger, scorn, revulsion, guilt, rejection, self-dissatisfaction, and sadness—especially in response to perceived stress.

A related construct, ruminative response style, refers to a cognitive and behavioral coping strategy, employed mainly by women, for responding to negative emotions, particularly dysphoria.

Nolen-Hoeksema proposed that, when experiencing emotional distress, women display a response style that emphasizes rumination, self-focus, and overanalysis of the problem and excessive focus on their own emotions. In contrast, men use more distraction and problem resolution. When ruminative responses are employed, they tend to intensify negative, self-focused thinking and to interfere with active problem solving, hence deepening or prolonging the symptoms of depression.

A series of studies has demonstrated support for these hypotheses, including gender differences in coping style and the association of ruminative coping with depression e. In view of the multiple biological, environmental, social, and personality risk factors for depression, research on risk for depression will be advanced by integrative, multivariable models that link biological factors with environmental and personal characteristics.

To date, however, the field is marked mainly by complex models that have not been empirically evaluated or by empirical tests of fairly limited integrative models. Many of the theoretical models have been focused on a particular subtopic, such as predicting outcomes and their mechanisms in children of depressed parents e. Broader models linking stress, HPA axis, and neurocognitive as well as cognitive and interpersonal factors, for example, are urgently needed.

Limited integrative empirical approaches that include biological factors are emerging, including complex quantitative genetic, environmental, and personal factors e. Studies that link neuroendocrine, stress, and social-cognitive factors are particularly needed. As this chapter has indicated, depression co-occurs with a host of stressful life events, early adversities, and ongoing strains, and it is also commonly associated with a variety of interpersonal difficulties and problematic traits and behavioral tendencies.

In both the original U. National Comorbidity Study and the recent replication, of all the community residents who met the criteria for lifetime or month major depression or both, approximately 75 percent had at least one other diagnosis, with only a minority having pure cases of depression Kessler et al. For patients with a diagnosis of current major depression, only 40—45 percent had depression in isolation, and 60—65 percent had at least one comorbid diagnosis; similar rates have been reported in different countries e.

Approximately 60 percent of comorbid disorders are anxiety disorders, particularly generalized anxiety disorder, panic disorder, social phobia, and posttraumatic stress disorders Mineka, Watson, and Clark, Among patients with anxiety disorders, approximately 30 percent have a comorbid mood disorder Brown et al.

The onset of anxiety disorders typically precedes the onset of depression, with earlier-onset anxiety disorders panic, social anxiety, generalized anxiety disorder predicting the subsequent first onset of depression Andrade et al.

So common is the overlap between depressive and anxiety disorders that some have argued that major depression and generalized anxiety disorder may virtually be the same disorder or closely associated, genetically mediated distress disorders e. Besides anxiety disorders, substance abuse and alcoholism and eating disorders are frequently accompanied by depressive disorders, in both clinical and community samples Rohde, Lewinsohn, and Seeley, ; Sanderson, Beck, and Beck, ; Swendsen and Merikangas, Several recent large epidemiological studies found rates of 25—30 percent for comorbid substance or alcohol abuse Davis et al.

In their analysis of the origins of the comorbidity of substance use disorders, Swendsen and Merikangas considered whether they share a causal relationship e.

Their data and review suggest a causal association, rather than shared etiology, for alcohol and depression, with evidence both for depression causing alcohol abuse and abuse causing depression. However, for other substance abuse, the patterns were inconsistent, suggesting that multiple mechanisms may be contributing to the comorbidity. Depending on the study, rates of personality disorders among depressed people range between 23 and 87 percent Shea et al.

One of the crucial problems with depression co-occurrence with other disorders is that the combinations may greatly complicate both the clinical course of depression and the efficacy of typical treatments. For example, the presence of a comorbid anxiety disorder predicts a significantly worse course of depression and dysthymia Brown et al.

Likewise, a comorbid personality disorder predicts a poorer outcome Daley et al. Serious acute and chronic diseases are highly stressful, and depression may be a reaction to the challenges associated with such problems; it can even result from the pathophysiological processes of certain diseases.

Of particular note is the role that depression may play as a contributor to ill health Katon, For example, depression may interfere with healthy lifestyle choices, such as regular exercise, smoking cessation, good nutrition, and compliance with medical treatments; dysfunctional self-care behaviors may play a causal role in the onset of certain diseases or in the course of disease and recovery e.

Furthermore, as noted earlier, depression has been linked with inflammatory processes that underlie several major diseases. Depression is associated with biological abnormalities, such as insulin resistance and secretion of inflammatory cytokines, which might contribute to diabetes onset Musselman et al.

Depression has been shown to be a predictor of heart disease progression or death in longitudinal studies of both initially healthy patients or in follow-up after first heart attack Frasure-Smith and Lesperance, ; Rugulies, ; Suls and Bunde, Depression with medical illness comorbidity is significantly more common among those with lower income, divorced or widowed, less educated, unemployed, and nonwhite Yates et al.

The rich literature on biological, environmental, and personal risk factors for depression also indicates a striking finding: not all individuals who have been exposed to risk factors for depression develop the disorder.

As a result, researchers have attempted to identify possible protective factors that serve as sources of resilience in the face of known risk.

A protective factor is a feature of the individual or the environment that is associated with a decreased probability of the development of a disorder among individuals exposed to factors that increase risk for the disorder. Resilience refers to the processes through which individuals overcome risk factors and adverse conditions and achieve positive outcomes. Similar to risk research, the investigation of sources of resilience has included biological, environmental, and psychological processes.

One of the challenges for researchers has been to avoid the pitfall of defining protective factors and processes of resilience as merely the absence of risk factors. That is, protective factors and evidence for resilience must be found in the presence of risk, not as a consequence of the absence of exposure to risk. The resilience research literature has focused largely on children exposed to adverse environmental conditions, with relatively less study devoted to depression specifically.

However, two key themes in the broader literature are important to note. One is that, across the range of resilience research over three decades, several variables appear universally to promote positive adaptation in children Masten, Among these are secure attachment and connection to competent and caring adults and positive family systems such as parental supervision , normal cognitive development and IQ, competent self-regulatory systems including agreeable personality traits, effortful control of attention and impulses, healthy executive functioning , positive outlook and achievement motivation, and peer, school, and community systems that promote positive values and opportunities.

The second theme in resilience science is an increasing emphasis on integrative, multilevel research on resilience in developing systems, drawing on biological, personality, cognitive, social, family, and environmental constructs that work together to promote adaptation and self-regulatory processes Masten, As specifically applied to resilience in the face of risk for developing depression, researchers have focused on biological factors, such as neuro-chemical, neuropeptide, and hormonal processes that mediate and moderate the relation between stress and depression e.

For example, brain structure, brain function, and neurotransmitters related to the ability to sustain positive affect in the face of stress and adversity may be characteristic of individuals who are exposed to chronic stress but who do not develop depression. Dopamine levels in the prefrontal cortex and the nucleus accumbens; serotonin levels in the prefrontal cortex, amygdala, hippocampus, and dorsal raphe; and levels of neuropeptide-Y in several cortical and subcortical regions have been implicated as protective factors against the risk for depression Charney, ; Southwick, Vythilingham, and Charney, Davidson et al.

In an interesting animal model of the role of controllable and uncontrollable stress, Amat et al. These researchers found that initial experience with controllable stress blocks intense activation of serotonergic cells in the dorsal raphe nucleus that would typically be produced by uncontrollable stress.

Furthermore, activity in the ventral medial prefrontal cortex PFC during initial controllable stress was required for the later protective effect to occur. This suggests that the ventral medial PFC is needed to process information about the controllability of stressors and to use such information to regulate responses to subsequent stressors. This finding is consistent with work by Davidson suggesting that the ventral medial PFC is involved in the representation of positive and negative affective states in the absence of immediately present incentives.

Research on biological processes related to resilience has been complemented by evidence for psychological and behavioral features of resilience—that is, research concerned with what resilient individuals think and do in response to exposure to risk factors that reduce the likelihood that they will develop depression.

Research has examined the psychological processes that are linked to these underlying neurobiological processes. Resilient individuals are not passive respondents to stress and adversity. Rather, those who are resilient are able to bring into action a set of skills to regulate thoughts and emotions and engage in behaviors that can resolve controllable sources of stress.

Active forms of coping are associated with resilience in response to controllable stressors. In contrast, accommodative or secondary control coping, including emotion regulation skills, are related to better outcomes in response to uncontrollable stress Compas et al. Cognitive reappraisal, or the ability to view a stressful or threatening situation in a more positive light, is an example of an emotion-regulation or coping process that is related to resilience to stress in adolescents and adults e.

The ability to use cognitive reappraisal to manage stress and emotions develops during adolescence along with the development of basic cognitive executive function skills. Cognitive reappraisal and other forms of secondary control coping skills, including acceptance and the ability to use positive activities as a form of distraction, are a source of resilience in adolescents of parents with a history of depression Jaser et al.

In a further study of adolescents whose parents have a history of depression, good-quality parenting despite depression and having a non-depressed parent or other adult to turn to were found to predict resilient outcomes Brennan, LeBrocque, and Hammen, Further integrative research on resilience mechanisms—as well as on interventions—is needed to support efforts to break the chain of intergenerational transmission of disorder and impairment.

Much is known about risk factors for depression, but further research is needed to test models of how multiple biological and psychosocial factors work together and to clarify the mechanisms by which stressful experiences lead to depressive reactions in individuals and in the family context.

Similarly, the processes by which resilient outcomes occur despite exposure to parental depression and other adverse conditions are vastly complex, and research will benefit from developmentally sensitive and integrative models that can be tested over a longitudinal course. We need to know more about optimal timing and methods of intervention to prevent the development and escalation of depression in those at greatest risk—especially young people during their formative family and career years.

Depression is highly prevalent and, for many, a chronic or recurring problem that interferes with work and family. It erodes the motivation, energy, and enjoyment needed to nurture and sustain marital, parenting, and social relationships. It is a disorder with many faces—starting at different ages, possibly chronic or waxing and waning, and typically mixed with a variety of other complicating problems, such as anxiety disorders, substance abuse, and behavioral disorders. It frequently occurs as a causal factor or contributor to medical illnesses.

There is considerable information on depression prevalence and manifestations in the general population, but less information specifically about depression in adults who are parents and caregivers. Children of depressed parents are at great risk for depression and maladjustment in academic, social, and intimate roles, and depressed parents have difficulty functioning effectively in their parenting and marital roles.

Risk factors and causal mechanisms involved in depression have implicated a wide range of biological genetic, neurological, hormonal, and endocrinological factors that may play a role in underlying vulnerability or in the processes by which stressors trigger depression in some people.

Fundamentally, etiological models are diathesis-stress models, in which stressful experiences—whether early childhood trauma, acute recent life events, or ongoing chronic strains—trigger depression.

Depression will most commonly be found among those facing chronically stressful conditions, such as social disadvantage and distressed relationships or lack of supportive and intimate relationships.

There are numerous individual characteristics that moderate or mediate the effects of stress on depression, including personality traits that reflect emotional reactivity and negativity, as well as styles of thinking about self and the world that emphasize beliefs about worthlessness, helplessness, and futility. Skills for coping with adversity that are passive, avoidant, and ineffective may perpetuate depression. Unraveling the complex and interlocking contributors to depression requires more integrative and long-term study than has yet been conducted or supported.

Substantial gaps occur in the application of knowledge about etiology to the detection and early treatment of depression. What may help a depressed teenage mother could be very different from what is needed by an adult depressed father—or by the same young woman after several bouts of major depression.

Treatments or preventive interventions that are effective for reducing depressive symptoms may not resolve the underlying family or economic difficulties that erode sustained mental health. Thus, no simple prescriptions for treatment or prevention are realistic, and different individuals and settings will need different but multifaceted, flexible, and long-term care that recognizes that depression affects the whole family and that supports recovery rather than cure.

Turn recording back on. National Center for Biotechnology Information , U. Search term. Clinically, earlier age of onset is associated with a worse course of depression with greater chances of recurrence, chronicity, and impairment.

Etiologically, first onset of depression at different ages e. Many individuals may experience a single, major depressive episode following an acute stressor and recover with little implication for future vulnerability. However, most 50—80 percent who have one significant episode will have recurrent episodes and intermittent subclinical symptoms, with the risk of recurrence progressively increasing with each episode of major depression.

Biological Factors Genetic, neurological, hormonal, immunological, and neuroendocrinological mechanisms appear to play a role in the development of major depression, and many of these factors center around reactions to stressors and the processing of emotional information. Etiological processes may be modified by gender and developmental factors. Environmental and Personal Vulnerabilities Etiological models for depression are largely diathesis-stress models in which stressful experiences trigger depression in those who may be vulnerable due to biological and psychosocial characteristics and circumstances.

Environmental stressors associated with depression include acute life events, chronic stress, and childhood exposure to adversity. Personal vulnerabilities associated with depression include cognitive, interpersonal, and personality factors. Biological, environmental, and personal vulnerabilities interact to contribute to the development of depression and also may be affected by depressive states in a bidirectional process.

Co-Occurring Disorders Depression rarely occurs independent of other psychological disorders, including anxiety, substance abuse, behavioral, and personality disorders, as well as other medical illnesses. The presence of co-occurring psychological and medical disorders exacerbates the clinical and social consequences of depression, and makes it more challenging to treat.

Resilience and Protective Factors Certain biological, environmental, and personal factors have also been associated with the protection from or the overcoming of risk factors and adverse conditions related to the development of depression. Age of First Onset First onset can occur at any time.

Course of Depression The course of depression may shed light on both treatment and prevention concerns and etiological issues. Genetic Vulnerability It is well known that depression runs in families, a phenomenon implicating both genetic and environmental processes.

Immune System Processes and Depression Spurred in part by the evidence of the strong association between depression and coronary heart disease, researchers have begun to examine the potential role of the immune system, and particularly proinflammatory cytokines, in the link between stress and depression e. Acute Life Events A major risk factor for depression is the experience of undesirable, negative life events.

Chronic Stress Acute, episodic life events tell only part of the depression story. Exposure to Early Adversity In addition to recent negative events and chronically stressful conditions, increasing evidence focuses on the link between childhood exposure to adversity and the development of depression in adolescence or adulthood.

Personal Vulnerabilities to Depression As noted earlier, etiological approaches to depression commonly invoke diathesis-stress models, in which stress precipitates depressive reactions among those with particular vulnerabilities. Cognitive Vulnerability to Depression Considerable research on depression in the past 40 years has focused on three variants of cognitive models of depression—the classical cognitive triad model negative views of the self, world, and future of Aaron Beck e.

Interpersonal Vulnerabilities to Depression Depressive disorders are known to be associated with considerable impairment in interpersonal functioning—marital discord, intimate partner violence, parenting difficulties, insecure attachment, and low social support, to mention several specific areas. Personality Vulnerabilities Space prevents the elaboration of the many candidates for personality traits and habits that might constitute vulnerability to depression, but we mention two factors that have received considerable recent attention: neuroticism and ruminative response style.

Integrative Research In view of the multiple biological, environmental, social, and personality risk factors for depression, research on risk for depression will be advanced by integrative, multivariable models that link biological factors with environmental and personal characteristics.

RESEARCH GAPS Much is known about risk factors for depression, but further research is needed to test models of how multiple biological and psychosocial factors work together and to clarify the mechanisms by which stressful experiences lead to depressive reactions in individuals and in the family context.

Hopelessness depression: A theory-based subtype of depression. Psychological Review , 96 , — Abramson, L. Learned helplessness in humans: Critique and reformulation. Journal of Abnormal Psychology , 87 , 49— Afifi, T. Social Psychiatry and Psychiatric Epidemiology , 41 , — Aguilar-Gaxiola, S. Monograph No. Sacramento: University of California, Davis. Alloy, L. The adolescent surge in depression and emergence of gender differences: A biocognitive vulnerability-stress model in developmental context.

Romer, editor; and E. Walker, editor. New York: Oxford University Press. Role of parenting and maltreatment histories in unipolar and bipolar mood disorders: Mediation by cognitive vulnerability to depression.

Clinical Child and Family Psychology Review , 9 , 23— Alpert, J. Social phobia, avoidant personality disorder and atypical depression: Co-occurrence and clinical implications. Psychological Medicine , 27 , — Amat, J. Previous experience with behavioral control over stress blocks the behavioral and dorsal raphe nucleus activating effects of later uncontrollable stress: Role of the ventral medial prefrontal cortex.

Journal of Neuroscience , 26 , — Andrade, L. Dragomirecka, E. International Journal of Methods in Psychiatric Research , 12 , 3— Andrews, B.

Social support, onset of depression and personality: An exploratory analysis. Social Psychiatry and Psychiatric Epidemiology , 23 , 99— Angold, A. Pubertal changes in hormone levels and depression in girls. Psychological Medicine , 29 , — Bailey, D.

Maternal depression and developmental disability: Research critique. Banks, K. The influence of racial identity profiles on the relationship between racial discrimination and depressive symptoms. Journal of Black Psychology , 33 , — Barrett, A. Family structure and mental health: The mediating effects of socioeconomic status, family process, and social stress. Journal of Health and Social Behavior , 46 , — Beck, A. Depression: Clinical, Experimental, and Theoretical Aspects. New York: Harper and Row.

Cognitive Therapy and the Emotional Disorders. New York: International Universities Press. Bifulco, A. Predicting depression in women: The role of past and present vulnerability. Psychological Medicine , 28 , 39— Exploring psychological abuse in childhood: II.

Association with other abuse and adult clinical depression. Bulletin of the Menninger Clinic , 66 , — Adult attachment style. I: Its relationship to clinical depression.

Social Psychiatry and Psychiatric Epidemiology , 37 , 50— Birmaher, B. Childhood and adolescent depression: A review of the past 10 years: Part I. Journal of the Academy of Child and Adolescent Psychiatry , 35 , — Blatt, S. Parental representations and depression in normal young adults. Journal of Abnormal Psychology , 88 , — Blazer, D.

The prevalence and distribution of major depression in a national community sample—the National Comorbidity Survey. American Journal of Psychiatry , , — Bloch, M. Risk factors associated with the development of postpartum mood disorders. Journal of Affective Disorders , 88 , 9— Blustein, J. Elevated depressive symptoms among caregiving grandparents.

Health Services Research , 39 , — Bockting, C. Prediction of recurrence in recurrent depression and the influence of consecutive episode on vulnerability for depression: A 2-year prospective study.

Journal of Clinical Psychiatry , 67 , — Boris, N. The process and promise of mental health augmentation of nurse home-visiting programs: Data from the Louisiana Nurse-Family Partnership. Infant Mental Health Journal , 27 , 26— Boyce, W. Biological sensitivity to context: I. An evolutionary-developmental theory of the origins and functions of stress reactivity. Development and Psychopathology , 17 , — Brennan, P. Maternal depression, parent-child relationships and resilient outcomes in adolescence.

Brieger, P. Frequency of comorbid personality disorders in bipolar and unipolar affective disorders. Comprehensive Psychiatry , 44 , 28— Brouwer, J.

Prediction of treatment response by HPA-axis and glucocorticoid receptor polymorphisms in major depression. Psychoneuroendocrinology , 31 , — Brown, C. Treatment outcomes for primary care patients with major depression and lifetime anxiety disorders. Brown, G. Social Origins of Depression. New York: Free Press. Aetiology of anxiety and depressive disorders in an inner-city population: 1.

Early adversity. Psychological Medicine , 23 , — Brown, J. Childhood abuse and neglect: Specificity of effects on adolescent and young adult depression and suicidality.

Brown, T. Current and lifetime comorbidity of the DSM-IV anxiety and mood disorders in a large clinical sample. Journal of Abnormal Psychology , , — Burke, H. Depression and cortisol responses to psychological stress: A meta-analysis. Psychoneuroendocrinology , 30 , — Burke, K. Age at onset of selected mental disorders in five community populations. Archives of General Psychiatry , 47 , — Burton, E. A prospective test of the Stress-Buffering Model of Depression in adolescent girls: No support once again.

Journal of Consulting and Clinical Psychology , 72 , — Cairney, J. Stress, social support and depression in single and married mothers. Social Psychiatry and Psychiatric Epidemiology , 38 , — Calvete, E. Cognitive and coping mechanisms in the interplay between intimate partner violence and depression.

Anxiety, Stress and Coping , 20 , — Campbell, J. Health consequences of intimate partner violence. The Lancet , , — Carnelley, K. Depression, working models of others, and relationship functioning. Journal of Personality and Social Psychology , 66 , — Caspi, A. Influence of life stress on depression: Moderation by a polymorphism in the 5-HTT gene.

Science , , — Charney, D. Psychobiological mechanisms of resilience and vulnerability: Implications for successful adaptation to extreme stress. Chin, M. Interventions to reduce racial and ethnic disparities in health care.

Clark, D. New York: Wiley. Clark, L. Separate personality traits from states to predict depression. Journal of Personality Disorders , 17 , — Cole, D. Individual differences in the emergence of depressive symptoms in children and adolescents: A longitudinal investigation of parent and child reports. Compas, B. Coping with stress during childhood and adolescence: Problems, progress, and potential in theory and research.

Psychological Bulletin , , 87— Coping and emotion regulation: Implications for understanding depression during adolescence. Nolen-Hoeksema, editor; and L. Hilt, editor. New York: Routledge. Coryell, W. The enduring psychosocial consequences of mania and depression. Coyne, J. Depression and the response of others.

Journal of Abnormal Psychology , 85 , — Marital quality, coping with conflict, marital complaints, and affection in couples with a depressed wife. Journal of Family Psychology , 16 , 26— Crouch, M. The evolutionary context of postnatal depression. Human Nature , 10 , — Cutrona, C. Neighborhood characteristics and depression: An examination of stress processes. Current Directions in Psychological Science , 15 , — Cyranowski, J.

Adolescent onset of the gender difference in lifetime rates of major depression: A theoretical model. Archives of General Psychiatry , 57 , 21— Daley, S. Depression and Axis II symptomatology in an adolescent community sample: Concurrent and longitudinal associations. Journal of Personality Disorders , 13 , 47— Dalgard, O.

Negative life events, social support and gender difference in depression. We'll talk more about antidepressant medications in the treatment section of this center. The neurotransmitter serotonin is involved in controlling many important bodily functions, including sleep, aggression, eating, sexual behavior, and mood.

Serotonin is produced by serotonergic neurons. Current research suggests that a decrease in the production of serotonin by these neurons can cause depression in some people, and more specifically, a mood state that can cause some people to feel suicidal.

In the s, the "catecholamine hypothesis" was a popular explanation for why people developed depression. This hypothesis suggested that a deficiency of the neurotransmitter norepinephrine also known as noradrenaline in certain areas of the brain was responsible for creating depressed mood. More recent research suggests that there is a group of people with depression who have low levels of norepinephrine.

Autopsy studies show that people who have experienced multiple depressive episodes have fewer norepinephrinergic neurons than people who have no depressive history. However, research results also tell us that not all people experience mood changes in response to decreased norepinephrine levels.

Some people who are depressed actually show more than normal within the neurons that produce norepinephrine. More current studies suggest that in some people, low levels of serotonin trigger a drop in norepinephrine levels, which then leads to depression.

Another line of research has investigated linkages between stress, depression, and norepinephrine. Norepinephrine helps our bodies to recognize and respond to stressful situations. Researchers suggest that people who are vulnerable to depression may have a norepinephrinergic system that doesn't handle the effects of stress very efficiently. The neurotransmitter dopamine is also linked to depression. Dopamine plays an important role in controlling our drive to seek out rewards, as well as our ability to obtain a sense of pleasure.

Low dopamine levels may, in part, explain why people with depression don't get the same sense of pleasure out of activities or people that they did before becoming depressed. In addition, new studies are showing that other neurotransmitters such as acetylcholine, glutamate, and Gamma-aminobutyric acid GABA can also play a role in depressive disorders.

In most cases, depression involves the interaction of biological and psychosocial factors. The impact of biological factors seems to be more prominent in major depressive syndrome, where typical symptoms and signs such as decrease in weight, changes in libido, dysmenorrhea, and sleeping disorders cannot be explained on psychodynamic grounds alone. Some of the symptoms and signs typical of patients suffering from depression reflect a primary disorder of biochemical and neurophysiological functions and are not commonly found in other forms of psychic disturbances.

Studies related to monoamine noradrenaline, serotonin or 5-HT, dopamine metabolism have assumed a major role in biochemical research into depression; this research now also includes studies on other central neurotransmitters such as GABA and glutamic acid, and neuropeptides like somatostatin and corticotropin-releasing factor CRF.