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– ETIOLOGICAL PROFILE & RISK FACTORS:
Major etiological drivers include genetic predispositions (autosomal patterns and chromosomal translocations) and environmental triggers like toxic chemical exposure, mechanical stress, or chronic viral infections.
â– MOLECULAR PATHWAY DYNAMICS:
Intracellular cascades undergo profound modifications, altering secondary transcription levels and receptor presentation on cellular membranes.
[HY-BOARD-1063]
🌟 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. Assess family history and genetic screens to identify high-risk patients before symptoms present. Therapeutic molecules targeting upstream signaling components demonstrate superior efficacy profiles.