Is it an epileptic seizure?
The first question is not “Which drug?” It is “What happened?” A careful history is often more informative than any single test.
History, history and history
Build the story before, during and after the event. Ask the person, the witness, and whenever appropriate review a safe smartphone video. Look for triggers, prodrome, stereotyped symptoms, duration, responsiveness, movements, colour change, tongue injury, incontinence, recovery and post-event confusion or focal weakness.
Syncope / fainting
Often triggered by standing, heat, pain or dehydration; pallor and presyncopal symptoms may occur. Brief jerks can occur during syncope and do not automatically mean epilepsy.
Functional / dissociative seizures
Real, involuntary events that are not caused by epileptic electrical discharges. Diagnosis should be positive and careful, often supported by video-EEG when needed.
Migraine phenomena
Aura can cause visual, sensory, language or neurological symptoms. Evolution over minutes and headache context can help, but overlap with focal seizures is possible.
Sleep disorders
Parasomnias, REM behaviour disorder and other sleep events can resemble nocturnal seizures; timing, stereotypy and video history are useful.
Movement disorders and behavioural events
Tics, dystonia, tremor, stereotypies, panic episodes and behavioural spells may be mistaken for seizures.
Other acute medical causes
Hypoglycaemia, intoxication or withdrawal, infection, metabolic disturbance and acute brain injury may provoke seizures or seizure-like collapse.
EEG supports the diagnosis; it does not replace it
A normal routine EEG does not rule out epilepsy, and an abnormal EEG does not by itself prove that a person's episodes are epileptic. Clinical context remains central.