NS - Depression and Bipolar Disorder

What is Depression?

- Depression is the state of having low mood for a prolonged period of time
- The intensity can be described as Intermittent (acute) or Chronic
- The source can be from certain events/situations or non-specific (accumulation of multiple events/situations)

Describe the symptoms and diagnosis for Depression

- A major depressive episode is defined by having AT LEAST 5 of the following symptoms, in THE SAME 2 WEEK PERIOD, and having a CHANGE FROM PREVIOUS FUNCTION:
1*) Depressed mood (EITHER OR)
2*) Anhedonia (EITHER OR)
3) Significant weight loss
4) Insomnia
5) Agitation
6) Fatigue
7) Feeling worthless
8) Diminished ability to think/concentrate
9) Recurring thoughts of death/suicide

Describe the potential causes of Depression

- Genetic predisposition show higher likelihood of developing depression
- Environmental factors that can cause heightened stress/social isolation
- Co-morbidities such as terminal/chronic illness, drug abuse, neurological disease and etc. (Debilitating conditions)
- Anxiety can manifest from depression, or depression can come from anxiety

What are the types of Depression?

- Unipolar depression = mood swing in one direction and most common; mostly caused by environmental causes, but some are genetic
- Bipolar depression = oscillating between depression and mania, and much less common

What are the types of Unipolar Depression?

- Depressive Disorder = (qualifies for depression diagnosis) Significant levels of sadness, lacking energy and self-worth
- Dysthymic Depressive Disorder = Similar to major depressive disorder, but less severe and longer lasting
- Major Depressive Disorder = severe depression patterns, debilitating and not caused by drugs or other medical conditions

Describe the theories of Depression

- Monoamine Theory = suggests link between reduced serotonin release and depressive episodes (found through Serotonin reuptake inhibitors)
- Neuroendocrine Theory = suggests hyperactivity in hypothalamus, leading to increased cortisol release from adrenal cortex
- Neuroplasticity Theory = loss of brain matter in hippocampus and prefrontal cortex, causing depressive episodes

What are the pharmacological treatments for Unipolar Depression?

- SSRIs (Selective Serotonin Reuptake Inhibitors) and SNRIs (Serotonin and Noradrenaline Reuptake Inhibitors) are the main drug classes prescribed
- They work by increasing synaptic Serotonin concentration
- SNRIs have more side effects, but noradrenaline is part of certain motivational pathways
- TCAs (Tricyclic Antidepressants) and MAOs (Monoamine Oxidase Inhibitors) are not prescribed often as they have more side effects, but still work to increases synaptic Serotonin concentration

What are the non-pharmacological treatments for Unipolar Depression?

- Cognitive Behaviour Therapy (CBT) = talking therapy to reframe how the patient thinks (often given alongside medication)
- Electroconvulsive therapy = patient is shocked in hemispheres of the brain (unilateral for one or bilateral for both), whilst under anaesthesia to "restart the brain" (administered in most severe cases when symptoms are debilitating)

What are the symptoms of Bipolar Disorder?

- Mania = erratic impulsive behaviour, elevated mood, short attention span, irritable, etc. (Present for at least a week + impair ability to work/socialise)
- Hypomania = same as mania but less severe (Present for at least 4 days + doesn't impair ability to work/socialise)
- Depression

What are the types of Bipolar Disorder?

- Cyclothymic Disorder = cycling between mild mania and mild depression
- Bipolar II Disorder = cycling between hypomania and depression (may be diagnosed as Unipolar Depression)
- Bipolar I Disorder = cycling between mania and depression
- Mixed Affective Episodes = pairing manic and depressive thoughts at the same time (High risk of suicide)

How is Bipolar Disorder diagnosed?

- Diagnosis comes from the symptoms of mania, hypomania and depression
- Tests are done to rule out the following conditions: Epilepsy, Brain lesions, HIV and Parkinson's
- Often, the first symptoms tend to be depressive in nature

Describe the potential causes of Bipolar Disorder

- Genetic link = candidate genes may predispose individuals to developing Bipolar Disorder, and may be common among family members
- Environmental = early life stressors or traumatic experiences
- "Kindling Hypothesis" = this refers to a small stimuli that intensifies over time, decreasing the stress threshold needed for an episode

Describe the theories of Bipolar Disorder

- Neuroanatomy = decreased neural matter and activity (from enlarged ventricles, smaller hippocampus, and less grey matter)
- Neurotransmitter systems = Monoamine hypothesis; decreases Dopamine and Serotonin cause decreased mood, and decreased Noradrenaline cause decreases "energy" (and vice versa)
- Neurotrophic factors = pruning of neural routes during brain development from stressful events
- Neuroinflammation = psychological stress potentially causing cellular stress

What are the pharmacological treatments for Bipolar Disorder?

- Lithium = shown to have mood stabilising effect, with involvement in increasing Serotonin production; it has side effects of nephrotoxicity, dehydration, induced hypothyroidism and teratogenicity
- Anticonvulsants = reduce Monoamine fluctuations, and more effective against epileptic bipolar patients
- Antipsychotics = Atypical are more often used for anti-mania rather than mood-stabilising
- Anti-depressants = commonly not used as they increase monoamine activity so intensify manic episodes

What are the non-pharmacological treatments for Bipolar Disorder?

- Cognitive Behaviour Therapy (CBT) = talking therapy to reframe how the patient thinks (often given alongside medication)
- Electroconvulsive therapy = patient is shocked in hemispheres of the brain (unilateral for one or bilateral for both), whilst under anaesthesia to "restart the brain" (administered in most severe cases when symptoms are debilitating)