Not all psychoactive substances are considered psychedelic. There are a lot of compounds that alter our perception without inducing changes in our ontological perspective or causing us to hallucinate.
Psychoactive substances can affect our mood, thoughts, behavior, or emotions.
Substances such as coffee or tea, alcohol, kava, marijuana, or kratom, can be considered psychoactive without being inherently psychedelic.
Other psychoactive substances, such as LSD, DMT, magic mushrooms, or salvia, cause a shift in our perception and perspective of reality — which is what makes them psychedelic.
DXM (dextromethorphan) is an ingredient in over the counter cough medicine.
In high doses it produces dissociative hallucinations similar to ketamine or PCP.