Depression Flashcards
DSM Definition of MDD
A. Five or more within a two-week period, and presenting a change from previous functioning, at least one of the symptoms is
- Depressed mood most of the day, nearly every day
- Markedly decreased interest or pleasure in all, or almost all activities (anhedonia)
- Significant weight or appetite changes
- Insomnia or hypersomnia
- Fatigue or loss of energy in absence of physical exertion
- Psychomotor agitation
- Worthlessness or inappropriate guilt
- Diminished ability to think or concentrate
- Suicidality
Prevalence of MDD
- 12 month prevalence in US 10%
- 23% and 15% lifetime prevalence, female male
- Women twice as likely to report MDD
- Less prevalence in 60+ age group
Onset of MDD
- Mean age of first episode is 26, but onset is decreasing
- Early onset associated with greater frequency of depressive episodes
- Major life events strong predictor of initial depressive episodes, but this relationship diminishes with subsequent episodes
Course of Depression
- Variable course - some rarely experience remission, while others have years between episodes
- Early age of onset associated with more lifetime episodes, greater severity and greater suicidality
- Recovery typically begins within one year of onset
Relapsing Course of Depression
- Majority of cases experience complete remission from MDE
- 20-30% remain in partial remission (subclinical symptoms not MDE)
- Approx 80% with MDE will have at least one more episode
Incomplete inter-episodic recovery
- Increased likelihood of subsequent episodes
- Remission periods longer in early course of MD
PDD (Dysthymia)
A. Most of the day for more days than not for at least 2 years
B. Presence while depressed, 2+ of
- Poor appetite or overeating
- Insomnia or hypersomnia
- Low energy or fatigue
- Low self-esteem
- Poor concentration
- Feelings of hopelessness
- more unrelenting, chronic, less severe
DSM History of PDD
PDD first introduced in DSM-3 after they found more chronic circumstances
- DSM-4 had specificies but little differences observed in course
- DSM-5 simplified
- Can have diagnosis of both
- Prevalence is 0.5% of half year
Onset of PDD
- Early and insidious (childhood to early adulthood), higher likelihood of childhood maltreatment
- Higher rates of mood disorders in first degree relatives
- 10 to 25 more likely to have comorbid personality disorders and substance abuse
- If onset of PDD precedes MDD → greater likelihood of more frequent subsequent episodes
- 79% of people with PDD also experience an MDE at some point
Other Depressive Disorders
- All have in common sad, empty or irritable mood, and somatic and cognitive changes that affect functioning
Differ in duration, timing and presumed etiology
- Premenstrual dysphoric disorder
- Substance induced depressive disorder
- Disruptive mood dysregulation disorder
Specifiers include
- Seasonal patterns
- Peripartum onset
- Psychotic features
Family and Twin Studies Finding Biological Influences in Depression
Family Studies
- Relatives of patients with mood disorder show lower age of onset and more likely to have recurrent depressive episodes
Twin studies
- If genetic contribution, disorder more likely in identical than fraternal twins
- Higher severity and recurrence of MDD associated with higher rates of MDD in relatives and twins
Estimates of Heritability in Depression
- Higher in women (36-44%) than men (18-24%)
- Small positive association between 5-HTTLPR (serotonin transporter linked polymorphism) and suicidal behaviour and depressive traits
- Carriers of 5HTTLPPR short variant reported more depression symptoms, cases of diagnosed depression and suicidality as a function of stressful life events - gene x environment interaction
Neurotransmitter Systems and Depression
- Lower serotonin implicated in etiology of mood disorders but only in relation to other neurotransmitters (norepinephrine and adrenaline)
- Permissive hypothesis - when serotonin is low, other neurotransmitters permitted to range more widely - become dysregulated → mood disturbance
Learned Helplessness
Animal Studies
- Dogs who received inescapable shock subsequently didn’t try to escape
Human Studies
- Similar patterns
- Propose that when humans learn they have no control over reinforcements in life
- Theory modified - attribution helplessness theory - depressed individuals attributed lack of control to internal, global and stable cause
Response Style Theory of Depression
The idea that an individuals response to their symptoms influences the duration, severity and course
- Ruminative response style – focusing on causes, meanings, and consequences
- Increases likelihood of developing depression and impair remission
- Predicts depression onset and duration
- Predicted depressive symptom 7 weeks post-earthquake
Cognitive Model of Depression
- Depression results from tendency to negatively interpret events
Types of thoughts implication in depression
- Negative schemas, beliefs, automatic thoughts
Cognitive triad
- Negative interpretations of self, world, future
Cognitive errors
- Overgeneralisation
- Black or white thinking
- Filtering
- Emotional reasoning
Responsiveness to Treatment of Depression
- 54% recover within 6 months, 70% in 12 months
- 12-25% don’t recover and develop unremitting chronic illness
Therapies for the highest Efficacy for Depression
- CBT
- IPT
- Behavioural activation
- Problem solving therapy
Antidepressants in the 50s
Monoamine oxidase inhibitors - stop the breakdown of NT’s serotonin and norepinephrine, leads to rise in activity
- High blood pressure side effects
- Rarely used
Tricyclics - block reuptake of NT’s serotonin & norepinephrine
- Side effects in overdose are cardiotoxic and potentially fatal