A Quick Introduction to Depression PDF

A Quick Introduction to Depression Dr Dylan Birk Intended Learning Outcomes Describe and apply the basic clinical features of depressive disorder, including diagnostic criteria List the causes and risks of developing a major depressive disorder, including both physiologi...

A Quick Introduction to Depression Dr Dylan Birk Intended Learning Outcomes Describe and apply the basic clinical features of depressive disorder, including diagnostic criteria List the causes and risks of developing a major depressive disorder, including both physiological and psychological (psychodynamic model) elements Introduction There are several different depressive disorders, which are normally characterised by low mood, anhedonia (loss of interest) and neurovegetative disturbance (physical symptoms eg change in appetite or sleep). This can have an impact on social life and work life. In this introduction, we will focus on major depressive disorder. Diagnostic Criteria There are two different sources of diagnostic criteria. There is the ICD-11 (international classification of diseases, 11th edition) or DSM-5 (diagnostic and statistical manual of mental disorders, 5th edition). ICD is produced by the World Health Organization whereas the DSM is produced by the American Psychiatric Association. During your training, you will work with some clinicians who prefer the ICD, and others who prefer the DSM. Despite some differences, they are largely similar in diagnostic outcome. ICD-11 CRITERIA FOR DEPRESSIVE DISORDER Symptoms are: Depressed mood Diminished interest/capacity for pleasure Change in sleep Psychomotor change Reduced energy; fatigue Feelings of worthlessness; excessive or inappropriate guilt Hopelessness Difficulty concentrating Recurrent thoughts of death or suicide Mild depression is diagnosed when no symptom is present to an intense degree and there is some, but not considerable, functional impairment. Moderate depression denotes several symptoms present to a marked degree and considerable but not complete functional impairment. Severe depression is diagnosed when many or most of the characteristic symptoms of depression are present to a marked degree, and/or several are present to an intense degree, and there is complete or near-complete functional impairment DSM-5 CRITERIA FOR MAJOR DERPRESSIVE DISORDER (INCLUDING DEPRESSIVE EPISODE) Five or more of the following symptoms have been present during the same 2-week period and represent a change from previous functioning. At least one of the symptoms is either depressed mood or loss of interest or pleasure (anhedonia): Depressed mood most of the day, nearly every day, self-reported or observed by others Markedly diminished interest or pleasure in all or almost all activities, for most of the day, nearly every day Significant weight loss when not dieting, weight gain or decrease, or increase in appetite nearly every day Insomnia (hard to sleep/stay asleep) or hypersomnia (can’t stay awake despite good sleep) nearly every day Psychomotor agitation (ie mental or physical restlessness) or retardation (mental or physical slowing down) nearly every day Fatigue or loss of energy nearly every day Feelings of worthlessness or excessive or inappropriate guilt nearly every day Diminished ability to think or concentrate, or indecisiveness, nearly every day Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, a specific suicide plan, or a suicide attempt. In addition, these symptoms: Cause functional impairment (e.g., social, occupational) Are not better explained by substance abuse, medication side effects, or other psychiatric or somatic medical conditions In the DSM, there are three levels of severity: 1) Mild: few, if any, symptoms more than number required for diagnosis of major depression, the intensity of the symptoms is distressing but manageable, and the symptoms result in minor functional impairment 2) Moderate: the number of symptoms, intensity of symptoms, and/or functional impairment are between those specified for ‘mild’ and ‘severe’ depression 3) Severe: the number of symptoms is substantially more than that required to make the diagnosis, the intensity of the symptoms is seriously distressing and unmanageable, and the symptoms markedly interfere with social and occupational functioning The DSM-5 also defines ‘persistent depressive disorder’ as: depressed mood, for more days than not, for more than or equal to 2 years. Impairment compared with major depressive disorder may be less severe. During the 2 years, the patient has never been without symptoms for more than 2 months at a time. TREATMENT RESISTANT DEPRESSION Treatment-resistant depression is defined as the failure to respond to at least two different antidepressant drugs of different classes, taken at adequate doses for at least four weeks. Risk Factors There are a range of risk factors, including:  Female sex. Older age. Past history of depression. Personal, social, or environmental factors, such as relationship issues or breakdown, bereavement, stress, poverty, unemployment, homelessness, social isolation, discrimination, prejudice, or adverse childhood experiences Postpartum period. Past history of depression. Family history of depressive illness (first-degree relatives of a person with a 'major' depressive episode have a three-fold increased risk of depression) or suicide. History of other mental health conditions and/or substance misuse. Other chronic physical health conditions associated with functional impairment (such as diabetes mellitus, chronic obstructive pulmonary disease, cardiovascular disease, chronic pain syndromes, epilepsy, stroke disease) What Causes Depression? The cause of depression is unknown. It is a complex condition that arises from a combination of biological, psychological, and environmental factors. Here are some examples of areas of interest when it comes to understanding some factors that might contribute to depression. GENE-ENVIRONMENT INTERACTIONS There is some evidence that there could be genetic factors that can predispose an individual to depression. Studying families with multiple cases of major depression has identified some potential chromosomal regions which could be associated with depression. However, no single gene has been identified as a cause for depression. There is also some evidence of gene- environment interactions. For example, some studies have shown a link between adverse childhood experiences and some genes modification. BIOLOGICAL FACTORS HPA axis (hypothalamic-pituitary axis) dysregulation has been linked to depression. The HPA axis is a physiological system that controls the body's stress response. When activated by physical or emotional stress, the HPA axis releases monoamines like dopamine, noradrenaline, and serotonin, which ultimately leads to cortisol (a stress hormone) release from the adrenal gland. Some people who have been diagnosed with depression have been found to have higher levels of cortisol. Normally, homeostatic mechanisms would then lead to a reduction in CRH and thus a reduction in cortisol. However, suppression of CRH seems to be impaired in people with severe depression. Relaxation techniques such as mindfulness and exercise may help reduce cortisol in the body. Another potential biological mechanism is the monoamine-deficiency hypothesis. This theory that suggests that a deficiency in monoamine neurotransmitters (eg serotonin, dopamine, and noradrenaline) causes depression. This theory emerged from the observation that drugs increasing the levels of these neurotransmitters often have antidepressant effects. Some of the physical symptoms of depression could also be explained by a reduction in these neurotransmitters. For example, low levels of noradrenaline could lead to fatigue. Whilst this summarises the main two theories, there a range of other biological factors that could be involved. For example, there is evidence that gut microbiota changes can make products that alter the CNS and some evidence looking at the role of inflammation in depression. Feel free to check out the references if you are interested in these areas. PSYCHOSOCIAL FACTORS These factors can play a role in the development and maintenance of depression. These factors mat interact with biological factors that make an individual more susceptible to depression (eg genetics or inflammation). Some psychosocial factors include: Loss or grief Cultural factors eg stigmatization Trauma Marginalisation Financial difficulty ACEs (adverse childhood Work stress experiences) Social isolation Prejudice/discrimination Tools to Aid Diagnosis Depression is a clinical diagnosis. There are no diagnostic tests. However, there are some tools that clinicians can use to help screen for depression and monitor symptoms during treatment. PHQ-2 (Patient Health Questionnaire-2) The PHQ-2 is derived from the Primary Care Evaluation of Mental Disorders (PRIME-MD) tool and quickly and accurately screens for depression with only two questions: 'Over the past 2 weeks, have you felt down, depressed, hopeless?' 'Over the past 2 weeks, have you felt little interest or pleasure in doing things?' A positive response to either question warrants a further review at the diagnostic criteria for depression. PHQ-9 The PHQ-9 is a 9-item depression questionnaire that reflects the DSM-5-TR criteria. It classifies current symptoms on a scale of 0 (no symptoms) to 3 (daily symptoms). Repeating the PHQ-9 during treatment allows the clinician to objectively monitor response to therapy. You can find it on MDCALC here. EDINBURGH POSTNATAL DEPRESSION SCALE This scale is a 10-item questionnaire for postnatal women. A score of ≥10 suggests depression References American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th ed., text revision (DSM-5-TR). Washington, DC: American Psychiatric Publishing; 2022 First, M.B., Gaebel, W., Maj, M., Stein, D.J., Kogan, C.S., Saunders, J.B., Poznyak, V.B., Gureje, O., Lewis‐Fernández, R., Maercker, A., Brewin, C.R., Cloitre, M., Claudino, A., Pike, K.M., Baird, G., Skuse, D., Krueger, R.B., Briken, P., Burke, J.D. and Lochman, J.E. (2021). An organization‐ and category‐level comparison of diagnostic requirements for mental disorders in ICD‐11 and DSM‐5. World Psychiatry, [online] 20(1), pp.34–51 World Health Organization. International statistical classification of diseases and health related problems (ICD). 11th revision. Jan 2022 NICE (2023). Depression: What Are the Risk factors? [online] NICE. Belmaker, R.H. and Agam, G. (2008). Major Depressive Disorder. New England Journal of Medicine, [online] 358(1), pp.55–68. Wang, Q., Shelton, R.C. and Dwivedi, Y. (2018). Interaction between early-life stress and FKBP5 gene variants in major depressive disorder and post-traumatic stress disorder: A systematic review and meta-analysis. Journal of Affective Disorders, 225, pp.422–428 Keller, J., Gomez, R., Williams, G., Lembke, A., Lazzeroni, L., Murphy, G.M. and Schatzberg, A.F. (2016). HPA axis in major depression: cortisol, clinical symptomatology and genetic variation predict cognition. Molecular Psychiatry, [online] 22(4), pp.527–536 Knudsen, J.K., Bundgaard‐Nielsen, C., Hjerrild, S., Nielsen, R.E., Leutscher, P. and Sørensen, S. (2021). Gut microbiota variations in patients diagnosed with major depressive disorder—A systematic review. Brain and Behavior Lee, C.-H. and Giuliani, F. (2019). The Role of Inflammation in Depression and Fatigue. Frontiers in Immunology, [online] 10(1696).