When two or more substances interact to produce a combined effect greater than the sum of their individual effects, this is known as what?

• A. Synergistic effect
• B. Titration twelve step facilitation
• C. Two stepping
• D. Thirteenth stepping

Answer: (A)

The idea being tested is how two or more substances interact to produce an effect that is greater than the sum of their separate effects. When this happens, we call it a synergistic effect. This means the substances boost each other’s action in a way that isn’t simply additive, leading to a stronger overall outcome than you’d expect if you just added their individual effects.

Why this is the best fit: the term synergistic effect specifically describes that enhanced, more-than-additive outcome resulting from the interaction of substances, which matches the scenario described in the question.

Why the others don’t fit: the other terms refer to different concepts entirely. Titration relates to adjusting a dose carefully, not to how two substances interact to amplify effects. Twelve-step facilitation and the associated terms are about treatment approaches or social dynamics within recovery communities, not about pharmacologic or interactive effects.