Depression and bipolar disorder

What is a key distinction between depression and bipolar disorder?

Depression is characterized by persistent sadness, whereas bipolar disorder includes episodes of both depression and mania.

What are the possible explanations for the 10% decrease in hippocampal volume that is visible in depression?

• Neuroplasticity hypothesis - atrophy of mature neurons (shortened dendrites and decreased spine density) - shrinkage due to loss of connections

• Neurogenesis hypothesis - decreases neurogenesis in adults leads to less new neurons and neural precursors

What is the monoamine hypothesis?

• Depression is due to a functional deficit of monoamine neurotransmitters like serotonin, dopamine, and norepinephrine.

• Mania is due to a functional excess of monoamine neurotransmitters like serotonin, dopamine, and norepinephrine.

Doesnt explain delayed therapeutic onset e.g. of SSRIs

Stimulant drugs increase monoamine neurotransmitters but arent antidepressant

Name one side effect of tricyclic antidepressants (TCAs).

Sedative side effects due to H1 antagonism, including dry mouth and blurred vision.

(amitryptyline, nortriptyline)

What is Cognitive Behavioral Therapy (CBT) aimed at?

Stopping the negative cycle that influences emotion and behavior.

How does inflammation relate to depression?

Patients with depression often have increased levels of inflammatory markers which can induce depressive symptoms. Sometimes is a precursor for depression in patients taking inflammatory medication.

What is an example of a next-generation treatment for depression?

Ketamine, which acts as a glutamate NMDA receptor antagonist and has a rapid onset of activity.

What are some pharmacological treatments for bipolar disorder?

• Lithium - reduces excitatory DA and Glutamate neurotransmission, increases inhibitory GABA neurotransmission

• Antipsychotics - reduce monoamine activity - D2 and 5-HT2A antagonists (olanzapine, risperidone)

• Anticonvulsants - (valproate, carbamazepine)

What are the key criteria for a manic episode in bipolar disorder?

An abnormally and persistently elevated or irritable mood lasting at least a week, along with at least 3 symptoms from a specific list.

What can help enhance negative feedback to reduce HPA axis hyperactivity in depressed patients?

Antidepressants, particularly those that increase serotonin and norepinephrine levels, can enhance negative feedback mechanisms, thereby reducing HPA axis hyperactivity associated with depression.

Describe the effects of HPA axis hyperactivation in depression

Negative feedback, normally controlled by cortisol levels, is disrupted.

HPA axis hyperactivation leads to increased cortisol production, increased CRH, and increased size and activity of the pituitary and adrenal glands

What are SSRIs

Selective Serotonin Reuptake Inhibitors e.g. fluoxetine, sertraline

Increase synaptic 5-HT levels by inhibiting reuptake

What are SNRIs

Serotonin-Noradrenaline Reuptake Inhibitors e.g. venlafaxine, duloxetine

Increase synaptic 5-HT and NA

Can raise blood pressure, and generally worse side effects/withdrawal than SSRIs