The observations that both the setting in which a psychoactive drug is taken and an individual's expectations influence the drug's effect and individuals vary in their susceptibility to hypnosis best reflect which unifying theme in psychology?

Answer

People's experience of the world is highly subjective

Explanation

Psychoactive drugs are chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behavior. Those who take these drugs are in a their consciousness, their moods and also their thoughts are changed. Examples of these drugs are legal ones like tobacco, and alcohol as well as the illegal ones like heroine, cannabis and cocaine among others.