Please enable JavaScript.
Coggle requires JavaScript to display documents.
Depressive Disorders - Coggle Diagram
Depressive Disorders
What is
Depression
- major depressive disorder (MDD), persistent depressive disorder (PDD), bipolar disorder
- depression is the most common psychiatric disorder (16% of people experience it at some point in their lives)
dsm criteria for major depressive episode (MDD)
- emotional symtoms:
- depressed mood and anhedonia > key features of the disorder > if these are not experienced, then the disorder is not depression.
- depressed mood encompasses a range of negative mood states, like emptiness, hopelessness, distress, or feeling disappointed or disgusted at yourself.
- not uncommon to report a feeling of hating yourself.
- anhedonia is a markedly diminished interest or pleasure in all, or almost all, activities.
- not just an increase in negative feelings, but also a decrease in positive feelings.
- feelings of worthlessness, or excessive, inappropriate guilt
cognitive symptoms
- although most people with depression don't commit suicide, recurring thoughts of death, suicidal ideation, a specific plan or committing suicide, or a suicide attempt are important diagnostic criteria.
- depression doesn't just change what a person thinks, but also how they think.
- diminished ability to think, concentrate, or make decisions
- becoming indecisive, mind wanders constantly, etc
physical/somatic symptoms
- significant change in appetite or weight > unintentional
- insomnia
- hypersomnia
- psychomotor agitation > feeling jittery or feeling like they move in slow motion
- fatigue or loss of energy
persistent depressive disorder (dysthymia)
- less common than depression
- people experience additional symptoms, but fewer than what's seen in MDD.
- poor appetite/overeating (does not need to be accompanied by weight changes), insomnia/hypersomnia, low energy/fatigue, low self-esteem, poor concentration/difficulty making decisions, feelings of hopelessness.
- at least two of the above symptoms + low mood occur on most days for at least 2 years.
- the symptoms may ease but will return again within two months
environmental and other risk factors
- stress: general stress, or traumatic life events
- low socioeconomic status, substance abuse, and comorbid mental disorders (anxiety/schizophrenia)
- gender: women, especially trans women, and other gender-diverse people are more likely to develop depression.
- unclear why cis women are more prone than cis men
- social prejudice and misunderstanding play a role in depression for trans and gender-diverse people
mania
- abnormally elated euphoric. can also feel irritable and distractible.
- usually talkative and can work intently on goals.
- often feel on top of the world, god-like, or invincible > can lead them to do risky things like spending their life savings.
- manic episodes can last at least a week, and during this time the person barely sleeps and doesn't feel tired.
- most often associated with bipolar 1 disorder (not found in MDD or PDD)
- can result in hospitalisation or significantly interfere with the person's functioning and/or relationships.
- hypomanic episodes (bipolar 2 disorder) cause less impairment and have less severe symptoms
What Causes
Depression
beck's cognitive model of depression
- proposes that negative schemas and appraisals can contribute to the development of depression and its maintenance or contribution
- argues that people with depression hold a negative self-schema > will have negative beliefs about themselves.
- argues that these schemas won't affect someone until they're activated > will become activated after a person experiences significant life stessors.
attentional + memory bias
- people with depression are more likely to turn their attention to wards sad faces and interpret neutral faces as negative
- people with depression makes people more likely to remember negative events and interpret neutral events as negative
rumination
- repetitive and cyclic pattern of negative thinking where the same, or very similar thoughts, get recycled over and over again
- is both a symptom and cause of low mood
serotonin transporter gene 5HTT
- some people have two copies of the short serotonin transporter allele, some people have two long alleles, and some people have one short and one long one.
- people with two short alleles are more likely to develop depression after a stressful life event like trauma
- serotonin helps regulate our emotions and also other neurotransmitters in the brain, like dopamine
social factors
- factors like isolation tend to exacerbate depressive symptoms, but people with depression often experience symptoms that make it difficult to maintain friendships and social support.
- difficulty trusting people > seems to be underlying cognitive and biological processes involved.
- joint attention: a phenomenon common in social animals > our tendency to direct our own gaze to the location of someone else's gaze.
Treating
Depression
cbt
- talking therapy: the person describes their situation and the person and the therapist analyse it together.
- behavioural experiment: doing the thing that's feared and analysing the results together with the therapist.
behavioural activation
- involves the person getting out and doing stuff > schedules and then engages in a range of activities.
- prevents the person engaging in safety behaviours.
- gives the person agency and a sense of control, which is important to stop learned helplessness.
- works in a similar way to antidepressants by increasing serotonin and dopamine levels
antidepressants
- tricyclic antidepressants: work by preventing the reuptake of certain neurochemicals, especially norepinephrine and serotonin, but fell out of favour due to bad side effects (weight gain, blurred vision, etc)
- monoamine oxidase inhibitors (MAO inhibitors): increase the availability of neurotransmitters like serotonin and norepinephrine, but they work by preventing them from being broken down.
- the reuptake process involves the neurotransmitters being first broken down into its component parts > MAO inhibitors prevent this.
- tend to only be used in depression with psychotic features or when other treatments haven't worked.
- the drug interacts with some chemicals present in certain foods, and the drugs can be fatal.
- SSRIs increase the effect of serotonin so it can last longer.
- SNRIs block the reuptake of both serotonin and norepinephrine
- both work by restricting how much the body's levels of other neurotransmitters can fluctuate, stabilising the person's mood.
- all of the antidepressants work about as well as each other > genetics may cause one type to work better than another for a specific person
- 50% of people see a significant improvement in their symptoms. the other 50% may need to change drugs, add in another, or try a different dose > this helps a further 20-30% of people
- combining antidepressants with another form of therapy like cbt seems to help most people.
interpersonal therapy (IPT)
- helps to teach people the social skills that they need to resolve problems in their interpersonal relationships.
- helps empower the person by addressing deficits that they may have with their social skills
electroconvulsive therapy (ECT)
- used in severe cases of treatment-resistant depression.
- conducted under anaesthetic (unlike in the past)
- associated with short-term memory loss for a couple days after receiving therapy
- unclear how it works > may cause structural changes like helping new brain cells grow, or by increasing levels of serotonin and blocking the effect of stress hormones
transcranial magnetic stimulation (TMS)
- an electromagnetic coil is placed on the head and a small, focused pulse is delivered to a part of the brain.
- less intrusive than ECT.
- preferable to other techniques because the person doesn't need to be anaesthetised and the side effects are usually mild, like headaches.
- doesn't work as well as ECT in severe treatment-resistant depression or depression with psychotic features
.
serotonin, norepinephrine,
dopamine
- dopamine plays a role in regulating the expression of emotions, hunger and eating habits, and higher cognitive functions like self-regulation, impulse control, and planning > all disrupted in people with depression.
- dopamine is also involved in the brain circuits that control movement, possibly explaining psychomotor retardation in people with depression.
- dopamine plays a role in learning and reward. chronic stress can downregulate this system, possibly explaining the effects of anhedonia.
- chronic stress downregulates the norepinephrine system. serotonin-norepinephrine reuptake inhibitors are somethings prescribed with people with depression.
- epinephrine (adrenaline) and norepinephrine (noradrenaline) get released as part of the fight/flight response. when people and animals are exposed to stress over a long period of time, the body eventually can't manufacture enough norepinephrine to keep up with demand, and the body gets depleted and reduces the number of norepinephrine receptors
- the relationship between low serotonin and depression was first described in the 1960s > serotonin seems to regulate mood via its relationship with other neurochemicals, like norepinephrine and dopamine
- when serotonin levels are low, other neurochemicals become dysregulated and our moods can fluctuate wildly as a result.
learned helplessness
- the psychological effect that happens when an animal has been exposed to repeated and prolonged trauma that it can not escape.
- having no control over a situation teaches helplessness
- disrupts the norepinephrine system in a way similar to depression
thought errors
- disordered thinking habits:
- black and white thinking: someone evaluates a situation as either good or bad > no grey area.
- catastrophising/generalisation: a person looks at a single example and takes it to extreme/applies it to everything
- mind reading: a person is convinced that other people must be thinking bad things about them
- fortune telling: the idea that you know what's going to happen in the future, even with no evidence to support what you're thinking
- emotional reasoning: reasoning that's based more on emotion than reality