The danger with head injuries under the influence of substances is the masking of symptoms: tiredness, confusion, speech problems can be substance-related — or signs of a subdural hematoma.
Delayed intracranial bleeding can become symptomatic hours to days after the trauma. The classic textbook rule “observe for 24 h, have someone wake you” is conservative, but works in practice.
With clear warning signs: 112, no hesitation. With unclear symptoms: emergency room (ER) the same day, no self-triage.
In clubs, a fall from stage/DJ-booth height or down stairs is the most common variant. Awareness teams are often the first point of contact — with a head injury, 112 is usually called directly.