Affective Disorders Flashcards
How common is depression?
Prevalence 2-5%
1/5 will suffer at some point in their lives
Is depression more common in F or M?
2:1 F:M
What is the pathophysiology of depression?
Monoamine (MA) theory - depression associated with reduced noradrenaline or serotonin in brain
Antidepressants inhibit breakdown of MA rapidly but clinical improvements can take weeks
List the monoamine neurotransmitters
Imadazoleamines - histamines
Catecholamines - adrenaline, noradrenaline, dopamine
Indolamines - serotonin, melatonine
What are the core symptoms of depression?
1) Depressed mood for most of the day, every day
- Little variation in mood despite changes in time, circumstances or activity
- Possible diurnal variation (worse in morning and improving throughout day)
2) Anhedonia
3) Fatigue
What are the typical symptoms of depression?
Biological:
1) Poor appetite with marked unintentional weight loss
- >5% in past month
(Rarely inc appetite and weight gain)
2) Disrupted sleep
- Initial insomnia with early waking (3+ hrs)
3) Psychomotor retardation eg sluggish thought processes, limited spontaneous movement or restlessness
4) Decreased libido
5) Inability to concentrate
Plus:
6) Feelings of worthlessness or inappropriate guilt
7) Recurrent thoughts of death, suicidal ideation or suicide attempts
What is needed to diagnose depression?
At least 2 core symptoms + 2/more typical symptoms
Symptoms present every or nearly every day without significant changes throughout the day for over 2 weeks
Must represent a change from normal personality without alcohol/drugs, medical disorders or bereavement
List the ICD-10 categories for mild, moderate, severe depression
When should this be used?
Mild = 2 x core + 2 x typical Moderate = 2 x core + 3(+) typical Severe = 3 x core + 4(+) typical
First episode (further depressive episodes classified as recurrent depressive disorder)
List some ddx for depression
Psych - dysthymia, bipolar disorder, schizophrenia, anorexia nervosa, anxiety
Neuro - dementia, PD, HD, MS, stroke
Metabolic - hypoglycaemia, hypercalcaemia
Haem - anaemia
Inflammatory - SLE
Infections - syphilis, Lyme disease, HIV encephalopathy
Medications - anti-HTN, steroids, H2 blockers, sedatives, antipsychotics
Substance misuse - alcohol, BDZ, opiates
Sleep disorders
What psychotic symptoms may someone with depression suffer from?
Delusions eg poverty, guilt over things which could not be their fault, punishment, nihilism
Hallucinations eg auditory (accusatory, cries for help), olfactory (rotten food, faeces), visual (demons, corpses etc)
What investigations should be done for depression?
Bloods
- FBC: anaemia
- ESR
- B12/ filate
- TFTs
- Glucose
- Calcium
Urine toxicity Syphilis serology HIV Dexamethasone suppression test ACTH stimulation
What is the dexamethasone suppression test?
Dexamethasone reduces ACTH release in normal people
Thus taking dexamethasone should reduce ACTH and lead to decreased cortisol
Cortisol is measured either overnight (more common) or standard (3 days) after administration of dexamethasone
Why may pt with depression present with an abnormal dexamethasone suppression test?
NA inhibits corticotropin releasing factor, thus decreasing ACTH secretion by the pituitary, and in turn, cortisol secretion by the adrenal glands
Deficiency of brain NA can lead to both depressive symptoms and increased cortisol production
Episodes fo cortisol secretion are longer and more frequent in depressed patients, and the circadian rhythm of cortisol release is altered
Dexamethasone does not suppress plasma cortsol levels in pts cvs normal subjects
What is ACTH stimulation?
aka cosyntropin test / syncathen test
Measures the response of adrenal glands to ACTH (should release cortisol)
List some biological causes of depression (7)
1) Genetic serotonin transporter gene (FH++)
2) Abnormal concentrations of serotonin and other NTs
3) Disregulation of the HPA axis
- Inc cortisol in 50%
- Linked to adrenal hypertrophy and failed dexamethosone suppression test
4) Hypothyroidism
5) Postnatal
6) Chronic pain
7) Medications
List some psychological causes of depression (7)
1) Childhood trauma
2) PTSD
3) Low self esteem
4) Stress, lack of coping, lack of resilience
5) Attitudes and beliefs
6) Anxiety and guilt
7) Burden of chronic disease / comorbities
List some social causes of depression (8)
1) Isolation
2) Bereavement
3) Stress
4) Abuse
5) Relationships
6) SES
7) Homelessness
8) Education
List antidepressants which may be used in the management of depression
SSRIs = first line
SNRI - Serotonin noradrenaline re-uptake inhibitors
NARI - Noradrenaline re-uptake inhibitor
TCA - Tricyclics
MAOIs - Monoamine oxidase inhibitors
NASSA - Nonadreneric and specific serotonergic antidepressants
Give some examples of SSRIS
Fluoxetine Citalopram Escitalopram Sertraline Fluvoxamine Paroxetine
In which populations are SSRIs more commonly used?
Elderly
Anxiety
OCD
What are some side effects of SSRIs?
Nausea and vomiting common
Agitation
Sexual dysfunction - 70% affected and difficult to treat
Also dizziness, dry mouth, blurred vision
Which SSRIs prolong the QT interval?
Citalopram
Escitalopram
What is serotonin syndrome?
Acute toxic syndrome due to increased 5HT activity
How does serotonin syndrome present?
Confusion Myoclonic jerks and hyperreflexia Pyrexia and sweating GI symptoms Mood changes and mania Convulsions Death
When can serotonin syndrome occur?
Within a few hours of SSRI dose or dose changes
How is serotonin syndrome managed?
Symptomatic support
Give some examples of TCAs
Amitriptyline
Imipramine
Lofepramine
Dosulepin
How do TCAs work?
5HT and NA reuptake inhibition
Anticholinergic effects
Antihistaminergic effects
What are some side effects of TCAs?
Cardiotoxic:
- QT prolongation
- ST elevation
- AV block
Alpha adrenergic blockade:
- Postural HTN
- Sedation
What are some risks of TCAs?
Increased risk of manic switch in bipolar disorder
In which populations are TCAs less useful?
Elderly
Physically ill
Overdose risk pt
What is the mechanism of action of MAOIs?
Inhibition of MAO-A and MAO-B
MAO-A metabolises NA, 5HT and tyramine
MAO-B metabolises DA and tyramine
Thus increase storage and release of 5HT and NA
Give some examples of MAOIs
Phenelzine
Tranylcypromine
What are some side effects of MAOIs?
Postural HTN Restlessness Oedema Nausea Sexual dysfunction
What interaction is important to note for those taking MAOIs?
Interaction with tyramine containing foods
- Cheese
- Yeast extracts
- Hung game
- Some alcoholic drinks eg red wine
- Pickled herring
What is tyramine?
Naturally occurring monoamine compound and trace amine derived from the amino acid tyrosine
It is a catecholamine releasing agent
Unable to cross BBB thus is can only lead to non-psychoactive peripheral sympathomimetic effects
However a HTN crisis can result from ingestion of tyramine rich foods in conjunction with MAOI
What happens when someone taking MAOIs ingests foods rich in tyramine?
Tyramine is not inactivated by MAO
Tyramine causes catecholaime release = tachycardia, sweating, HTN, arrythmias, stroke, death
What are venlafaxine and duloxetine?
Serotonin and NA reuptake inhibitors
How do SNRIs work?
Dual action reuptake inhibitors
NA reuptake is only seen at higher doses
Which SNRI can cause HTN at higher doses?
Venlafaxine
Compare SNRIs and TCAs
SNRIs = ‘cleaner’ and safer in OD than TCAs
What is mirtazapine?
Noradrenergic and specific serotonergic antedepressant (NASSAs)
How does mirtazazapine work?
Presynaptic alpha 2 autoreceptor antagonist = thus enhances NA transmission
More sedative at LOWER doses due to its antihistaminergic effect predominating over its noradrenergic effects - useful in pt who cannot sleep
What are some side effects of mirtazapine?
Stimulates appetite, causes weight gain (may be useful in some pt), sedation classic (take at night)
LACKS CV and anticholinergic side effects
Less incidence of sexual dysfunction
What is the onset of action of antidepressants?
Myth that they do not exert effects for 2-4wks
ALL antidepressants show a pattern of response where rate of improvement is highest during weeks 1-2 and lowest during weeks 4-6
If no effect by 3-4 weeks, consider switching
What does the term discontinuation symptoms describe? When do they occur?
Used to describe symptoms experienced on stopping prescribed durgs that are not drugs of dependence = NOT WITHDRAWAL
Onset usually within 5 days of stopping treatment