Depression

Jonathan Tsun & Ilona Blee

Depression Symptoms 5 characteristic symptoms (ICD-10)

Depressed mood

Loss of interest and enjoyment

Reduced energy

Increased fatiguability

Diminished activity

Depression Symptoms

List some more common symptoms? Reduced concentration and attention

Reduced self-esteem and self-confidence

Ideas of guilt and unworthiness

Bleak and pessimistic views of the future

Ideas or acts of self-harm or suicide

Disturbed sleep

Diminished appetite

Anxiety and distress

Motor agitation or slowing of movements

3 Types Mild

depression At least two of:

Depressed mood; loss of interest and enjoyment; increased fatiguability

PLUS at least two more of the other symptoms

Minor functional impairment

Episode lasts at least 2 weeks

Moderate depression

At least two of: Depressed mood; loss of interest and enjoyment; increased fatiguability

PLUS at least three to four of the other symptoms

Considerable difficulty continuing with social, work, domestic activities

Episode lasts at least 2 weeks

Severe depression

All three of: Depressed mood; loss of interest and enjoyment; increased fatiguability

PLUS at least four of the other symptoms

Unlikely able to continue with social, work, or domestic activities (significant functional impairment)

Episode may last less than 2 weeks if symptoms are severe enough

**Can occur with or without psychotic symptomsNOTE: You can only classify single

episodes of depression as mild-severe.

2 Patterns Unipolar

Dysthymia – low mood

Melancholia – major depression

Atypical depression

Bipolar Bipolar disorder

Cyclothymia

Physiology of depression…

A bunch of guesswork, really…

Brain structures involved…

Mood stability depends on the balance between reward and

stress circuits of the brain

Which areas of the brain show decreased activity?

Prefrontal cortex

Deficits lead to problems with concentration, motivation, problem solving ability

Hippocampus

Deficits lead to memory problems

Which areas of the brain show increased activity? Amygdala

Fear conditioning centre of the brain

Hypothalamus

Start of the stress axis (HPA axis)

Theories for Depression Neurotransmitter

imbalance Serotonin

insufficiency Noradrenaline

insufficiency

Neurohormone imbalance Steroids HPA axis

Immune Inflammatory

response stimulate HPA axis

Circadian Changes in circadian

rhythms Seasonal Affective Disorder

Neurogenic Decreased spreading

of dendrites (arborisation)

Decreased synapses Neurotransmitter

overproduction

Selective Serotonin Reuptake Inhibitors

MoA: Inhibit 5HT reuptake into pre-synaptic cell

Allows elevated levels of 5HT to remain in the synaptic cleft and bind with post-synaptic cell

Side-effects: Slow onset

Nausea

Sexual dysfunction

Serotonin syndrome – excess serotonin (over-activation of ANS)

Examples: Fluoxetine (Prozac)

Citalopram

Paroxetine

Tricyclic Antidepressants MoA:

5HT reuptake blocker NA reuptake blocker α1 adrenoreceptor antagonist H1 receptor antagonist M1 receptor antagonist

Side-effects: Sedation – H1 receptor antagonist Dry mouth, eyes – M1 receptor antagonist Orthostatic hypotension – α1 adrenoreceptor antagonist

Examples: Amitriptyline Nortriptyline Cocaine

Monoamine oxidase inhibitors (A)

What is their mechanism of action?

Block breakdown of 5HT and NA by inhibiting enzymatic breakdown

This will increase 5HT/NA levels at the synapse

Name TWO examples of a monoamine oxidase inhibitor (A).

1. Phenelzine

2. Moclobemide

Why are monoamine oxidase inhibitors (A) or MAOIs

memorable? The only antidepressant drug to have the ‘cheese reaction’ as a

side effect

What is the ‘cheese reaction’? (I’ve broken it down into 4 basic steps)

1. Reaction to food containing tyramine

2. Normally this is broken down by monoamine oxidase

3. If left not broken down it can circulate in the body and be taken up by adrenergic neurons and cause the release of noradrenaline

4. This causes effects like hypertension, tachycardia and arrhythmias

List two other side effects of monoamine oxidase inhibitors (A).

1. Postural hypotension

2. Sleep disorders

Atypical antidepressants

Name TWO examples of an atypical antidepressant

1. Reboxetine

2. Venlafaxine

3. Buspirone

Reboxetine is a NaRI. What is its mechanism of action?

Same as SSRIs

What is the mechanism of action of buspirone?

5HT partial agonists reduce activity to increase transmitter levels – act on pre-synaptic terminals. Reduction of activity reduces extra growths which were being used to mop up excess neurotransmitter

Cognitive Behavioural Therapy

What conditions can CBT be beneficial for?

Depression

Anxiety and panic attacks

Addictions (e.g. pathological gambling)

Obsessive-compulsive disorder

Drug or alcohol problems

Eating disorders

Phobias

Chronic fatigue syndrome

What are the four aims of CBT?

1. Identify thinking that causes problematic feelings & behaviours

2. Question the individual’s negative thinking

3. Identify unwanted behaviour patterns

4. Plan behavioural goals and steps to achieve goals

CBT Techniques

Challenging irrational beliefs

Reframing/replacing them with alternative, rational thoughts

Thought stopping

Graded exposure

Assertiveness

Social Skills training

Problem solving training

Relaxation techniques

Which of the following drugs is NOT active as an antidepressant agent?

A. Amitriptyline

B. Fluoxetine

C. Moclobemide

D. Buspirone

E. Lithium

F. None of the above

Which of the following is NOT a known action of the antidepressant

agents?

A. Inhibition of monoamine neurotransmitter re-uptake

B. Block of amine deamination of monoamine neurotransmitter

C. Activation of dopamine D2 receptors

D. Antagonist of alpha-adrenoceptors

E. Increasing 5HT levels by inhibiting re-uptake pump

The “cheese reaction” is a known side effect of which class of antidepressant?

A. Selective serotonin reuptake inhibitors

B. Tricyclic antidepressants

C. Monoamine (A) oxidase inhibitors

D. Atypical antidepressants

E. Lithium

Thank you!

Any questions?