Topic: Neuropsychiatric and Cognitive Disorders
Learning Objectives:
• Understand the neurochemical basis of mood, cognitive, and psychotic disorders.
• Identify the pathophysiological mechanisms of depression, schizophrenia, anxiety, and
dementia.
• Describe neurotransmitter imbalances and structural brain changes in mental health
conditions.
• Apply knowledge of clinical presentation to differential diagnosis.
Key Concepts Summary:
1. Major Depressive Disorder (MDD)
• Caused by monoamine imbalance: ↓ serotonin, norepinephrine, dopamine.
• Involves dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis.
• Symptoms: anhedonia, low mood, fatigue, sleep/appetite changes.
• SSRIs increase serotonin availability at synapses.
2. Bipolar Disorder
• Alternating manic and depressive episodes.
• Mania: elevated mood, hyperactivity, decreased need for sleep, risky behavior.
• Linked to dysregulation of dopamine and glutamate.
• Treated with mood stabilizers (e.g., lithium).
3. Generalized Anxiety Disorder (GAD)
• Excessive worry ≥6 months.
• Neurotransmitter imbalance: ↓ GABA, ↑ norepinephrine.
• Somatic symptoms: muscle tension, restlessness, fatigue, insomnia.
• Benzodiazepines enhance GABA activity.
4. Schizophrenia
• Positive symptoms: hallucinations, delusions, disorganized thinking.
• Negative symptoms: flat affect, social withdrawal, anhedonia.
• Pathophysiology: