â– LECTURE OVERVIEW: Major Depressive Disorder (MDD) is a common, debilitating mood disorder diagnosed biochemically by meeting specific clinical criteria outlined in the DSM-5.
â– THE SIGECAPS CRITERIA:
1. Diagnostic threshold: Requires at least 5 of 9 symptoms present during the same 2-week period, representing a change from previous functioning, where at least one symptom must be depressed mood or anhedonia (loss of interest/pleasure).
2. The mnemonic:
- S - Sleep disturbances (insomnia or hypersomnia).
- I - Interest loss (profound anhedonia).
- G - Guilt or feelings of worthlessness.
- E - Energy depletion or fatigue.
- C - Concentration difficulties or indecisiveness.
- A - Appetite and weight changes (increase or decrease).
- P - Psychomotor agitation or retardation.
- S - Suicidal ideation or recurrent thoughts of death.
â– BIOCHEMICAL MECHANISMS:
At the molecular level, enzyme kinetics govern reaction rates. Competitive inhibitors raise apparent Michaelis constants without changing maximum speed, whereas noncompetitive inhibitors decrease maximum speed directly.
â– ACUTE TOXICOLOGICAL PROFILE:
High cumulative chemical exposure or accidental overdose triggers systemic receptor overload, cellular injury, and metabolic acidosis.
[HY-BOARD-1170]
🌟 Dynamic Clinical Key:
First-line pharmacological treatment is selective serotonin reuptake inhibitors (SSRIs; e.g., Sertraline, Escitalopram). Sexual dysfunction and weight gain are the most common reasons for treatment non-adherence and discontinuation. Focus on rate-limiting regulatory steps for pharmacological design. Immediate administration of physiological charcoal or specific receptor antagonists is lifesaving.