Seizure

A seizure is an episode of abnormal, synchronised electrical discharge across neurons that disrupts normal brain function. The disruption may appear as convulsions — the rhythmic jerking most people associate with the word — but it can equally present as a sudden freeze, a blank stare, an involuntary sensory disturbance, or a lapse of awareness lasting only seconds.

In the context of substance use, seizures matter because many compounds alter the threshold at which the brain tips into this state. Some raise the risk acutely, through a toxic dose; others raise it chronically through dependence, making withdrawal itself the danger. Seizure is part of the emergency vocabulary of harm reduction because it can appear without warning and requires a specific response.

How it is done

Seizure response is what witnesses do to reduce harm while the episode runs its course. The electrical activity cannot be interrupted from outside; the goal is to prevent injury and keep the airway open.

The area around the person is cleared of hard or sharp objects. The head is cushioned — a folded garment beneath it is enough. The person is not restrained; restraint does not shorten a seizure and increases the risk of injury to both parties. Nothing is placed in the mouth. The old instruction to prevent 'swallowing the tongue' reflects a misunderstanding of anatomy, and objects in the mouth cause harm.

The time the seizure begins is noted if possible. When convulsive movements stop and the person is breathing, moving them into the recovery position — on their side, head tilted back slightly to keep the airway open — reduces the risk of aspiration.

When it matters

A seizure lasting longer than five minutes, or a sequence of seizures without regained consciousness between them, constitutes a medical emergency known as status epilepticus. Prolonged seizure activity carries a risk of brain injury. Emergency services should be contacted if the seizure does not stop, if the person does not regain awareness, if they sustained a head injury in the fall, or if breathing is absent or obstructed.

Seizures during substance use carry additional urgency because bystanders rarely know the full picture — what was taken, in what amount, and what else the person uses regularly. Withdrawal from alcohol or certain sedatives can produce seizures that escalate in clusters; a first episode in this context is not self-limiting in the way a single event might suggest. Information about substances present is relevant to emergency responders and changes the care they provide.

What it cannot tell you

Witnessing a seizure does not establish what caused it. During substance use, a seizure may reflect a stimulant in toxic range, withdrawal from a depressant taken regularly, a combination of substances that interact on seizure threshold, or a neurological condition entirely unrelated to what was consumed that day. The outward appearance — how long it lasts, how violent the movements are — does not reliably distinguish between these.

A seizure ending does not mean the danger has passed. The post-ictal state that follows can involve prolonged confusion, combativeness, or unresponsiveness indistinguishable from unconsciousness, and a second seizure may occur before the person has recovered from the first. An episode that stops cleanly can still precede deterioration.