â– LECTURE OVERVIEW: Schizophrenia is a chronic, heterogeneous psychiatric disorder characterized by a disintegration of thought processes and emotional responsiveness.
â– DOPAMINERGIC PATHWAYS & RECEPTORS:
1. Positive Symptoms (Excess/distortion of normal function):
- Manifestations: Hallucinations, delusions, disorganized speech, and grossly disorganized behavior.
- Pathway: Driven by dopamine hyperactivity at D2 receptors selectively in the Mesolimbic pathway of the brain.
2. Negative Symptoms (Loss of normal function):
- Manifestations: Apathy, flat affect, alogia (poverty of speech), anhedonia, and social withdrawal.
- Pathway: Driven by relative dopamine hypoactivity at D1 receptors in the Mesocortical pathways.
â– PROGNOSTIC CRITERIA & TIMELINE:
Patient outcome scales correlate heavily with diagnostic staging at presentation, age, pre-existing comorbidities, and biological markers of cellular dividing rates.
â– GERIATRIC PHYSIOLOGIC ADJUSTMENTS:
Older patients display reduced physiological reserves, altered muscle-to-fat distributions, and distinct renal filtration profiles.
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🌟 Dynamic Clinical Key:
First-generation antipsychotics (e.g., Haloperidol, Chlorpromazine) are potent D2 blockers that treat positive symptoms but can worsen negative symptoms and cause extrapyramidal side effects. Second-generation atypical antipsychotics (e.g., Aripiprazole, Clozapine, Olanzapine) block 5-HT2A receptors alongside D2, offering better management of negative symptoms. Regularly reassess clinical parameters to adjust long-term therapy. Always adjust therapeutic doses based on age-related glomerular filtration clearance.