Mood disorders Flashcards
What are the main classes of psychiatric disorder?
- Psychoses (e.g. schizophrenia, bipolar, delusional disorder, drug-induces psychoses)
- Mood and anxiety disorders (neuroses)
- Eating disorders
- Substance use disorders
- Organic disorders
- Childhood disorders
- Personality disorders
What do mood disorders involve?
they involve a fundamental disturbance of
mood, usually accompanied by a change in activity level and other resultant symptoms
- They range from mild/bordering normality, to severe psychotic depression with hallucinations and
delusions
What are the two distinct types of mood disorder?
Unipolar – where mood changes are always in the same direction
Bipolar – where depression alternates with mania
Symptoms of depression
*Depressed mood – pervasive low mood
* Anhedonia
* Lethargy and reduced energy
Reduced concentration and functional
impairment
Impaired self-confidence; social withdrawal
Absence from work, relationship dysfunction
Ideas of guilt, anxiety, panic
Ideas/acts of self-harm/suicide
Disturbed sleep (early morning wakening)
Diminished appetite; reduced libido;
amenorrhoea
Feelings of hopelessness and helplessness
‘Mood-congruent’ delusions and
hallucinations
Diurnal variations in mood (morning worst)
Symptoms of mania
Abnormally elevated/irritable mood for at least one week Inflated self-esteem Reduced need for sleep Pressure of speech Racing thoughts Distractibility (useful for carers) Increase in goal directed behaviours Excessive pleasure seeking (drugs, sex) with harmful consequences
Describe course of illness of unipolar depression
average length of episode is 6 months, recovery from individual episodes is expected but
commonly persistent ‘subthreshold’ symptoms. Also 12-20% do not recover, and develop chronic
depression
Describe course of illness of bipolar depression
average length of manic episode is about 6 months, recovery from individual episodes is
expected but commonly there are persistent ‘subthreshold’ symptoms which are mainly depressive
Risk factors of unipolar depression
Lifetime risk = 10-20%
Female (2x more common than men)
perhaps as more likely to ‘ruminate’ over
thoughts
Early adulthood (mean age of onset is 25 yrs)
Previous episode (60% people experience
recurrence)
~75% is non-familial with a clear association with
stressful life events. Often with symptoms of anxiety
or agitation – reactive depression
Risk factors for bipolar depression
Lifetime risk = 0.5-1%
Equal sex incidence
Teenage (mean age of onset is 17 yrs)
Previous episode (90% recurrence)
Discuss monoamine hypothesis of depression
- caused by functional deficit of monoamine transmitters at certain areas of brain, where mania is excess
- unlikely to be the whole story, complex disease with many interacting factors
‘In people not at high risk of depression, monoamine depletion does not cause clinical depression, but in
those who are at risk (having previously had an episode) then depletion causes clinical recurrence’
Describe links between HPA axis and depression
- depressed patients hypersecerete cortisol
- patients with Cushing’s have a higher frequency of depression, resolves when cortisol is lowered
- high cortisol = brain atrophy and cognitive decline
- It has been proposed that continual exposure to cortisol due to stressful events can cause
death in hippocampal neurons, and this hippocampal degeneration sets off a vicious cycle
where the stress response becomes more pronounced and more hippocampal damage
ensues
Discuss depression and abnormal circuitry
fMRI studies of depressive patients suggest an
overactivity of the limbic system (emotional perception and appraisal) and underactivity of cortical
regulatory areas (dorsolateral prefrontal cortex).
Effective psychological treatments for unipolar depression
Persistent mild depression – guided self-help programme based on cognitive behaviour therapy
(psychotherapeutic approach that addresses dysfunctional emotions, maladaptive behaviours and
cognitive processes through a number of goal-orientated, explicit systematic procedures)
If not responsive then can have cognitive behaviour therapy, or interpersonal therapy (also couples
therapy if appropriate). Antidepressant drugs can also be prescribed with SSRIs as first line.
Moderate/severe depression should be treated with a combination of antidepressants and a high intensity
psychological intervention
Effective psychological and social treatments for bipolar depression
Psychological treatments which have been shown to be effective are CBT, interpersonal therapy and
family-focused therapy. Improves long-term prognosis especially if given early on in illness, as they have a
strong education component.
However in contrast to unipolar, medication plays a more important role. Conventional antidepressants do
not seem to be generally effective and also can cause a manic switch. Lithium treatment (stabilisation of
mood) is still the mainstay but may need to be augmented by atypical antipsychotics.
What are the main classes of antidepressants?
- tricyclics
- SSRIs
- MAO inhibitors
- selective serotonin and noradrenaline reuptake inhibitors (SNRIs)
Example of tricyclic antidepressant
Amitrypilline
Mechanism and side effects of tricyclics
The first class of drug used to manipulate the monoamine levels
Primary mechanism = inhibit reuptake of NA and 5-HT
They are still in use today + have proven effective in treating depression
But have unwanted side-effects
o The anti-muscarinic actions of TCAs can dry mouth, blurred vision, constipation
and urinary retention
o More seriously, risk of arrhythmias and heart block, which can lead to sudden
cardiac death
Example of SSRI
Fluoxetine
Example of selective serotinin and noradrenaline reuptake inhibitor
Venlafaxine
Describe SNRIs and SSRIs
Relatively mild side-effects
Decreased overdose toxicity in comparison to TCIs and MAOIs
Example of MAO inhibitor
Phenelzine
What do MAO inhibitors do? Side effects?
Block the enzymatic degradation of NA and 5-HT, resulting in increased levels of these NTs
in the synaptic cleft
Effective
Side effects:
- cheese reaction → normally harmless amines (such as tyramine) are ingested and are
normally broken down by MAO in the gut and liver so only small amounts reach circulation.
However, when MAOIs are present, these are absorbed and can result in acute
hypertension, throbbing headache and can even lead to intracranial haemorrhage due to its
sympathomimetic effect. These amines are commonly found in ripe cheeses.
o Hypertension
Risk of SEs has been reduced through development of reversible, selective inhibitors
targeting either MAO-A or MAO-B
Origin of monoamine theory of depression
1965, when it was discovered that substances such as
reserpine, an antihypertensive drug that reduces monoamine levels, administered lead to
some patients developing MDD
Discuss lithium
Mood stabiliser
Many proposed mechanisms
interacts with a number of neurotransmitters and receptors, decreasing norepinephrine release and increasing serotonin synthesis
Classification of anxiety disorders
Panic disorder Phobias OCD PTSD General
List the anxiolytics we need to know
GABA potentiation (barbiturates, benzodiazepines) → also have sedative effects 5HT1 agonists (buspirone is a 5-HT1a agonist → autoreceptor → reduces firing rate of serotonergic neuron) B-blockers (propranolol)
Side ffects of benzos
- sedating/muscle relaxing
- drowsiness/dizziness
- decreased libido and erection
- hypotension
- nausea
- cognitive impairment long term
dependence!
