Delirium tremens (DTs) is a severe and potentially life-threatening condition that arises as a complication of alcohol withdrawal. It typically occurs in people who have been drinking heavily and regularly for a long time and then suddenly stop or significantly reduce their alcohol intake. The underlying cause of delirium tremens is the brain’s reaction to the abrupt absence of alcohol, which it has become dependent on to function normally.
To understand what causes delirium tremens, it’s important to first grasp how alcohol affects the brain. Alcohol is a central nervous system depressant, meaning it slows down brain activity. When someone drinks heavily over a long period, their brain adapts to this constant depressant effect by increasing excitatory neurotransmitter activity and reducing inhibitory neurotransmitter activity to maintain balance. Specifically, alcohol enhances the effect of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that calms brain activity, and suppresses glutamate, an excitatory neurotransmitter that stimulates brain activity.
When alcohol consumption suddenly stops, this balance is disrupted. The brain, now without the calming influence of alcohol, experiences a surge in excitatory neurotransmitter activity, particularly glutamate, and a reduction in inhibitory GABA activity. This leads to a state of hyperexcitability in the nervous system. The brain and body become overactive, which manifests as the symptoms of alcohol withdrawal.
Delirium tremens represents the most extreme form of this withdrawal hyperactivity. It usually begins 48 to 72 hours after the last drink but can sometimes start up to 96 hours later. The condition is marked by a sudden and severe alteration in mental status and autonomic nervous system instability. The brain’s overexcited state causes confusion, disorientation, and vivid hallucinations—often visual, such as seeing small moving objects like insects or mice. Patients may also experience tactile hallucinations, feeling things that aren’t there.
Alongside these mental symptoms, the autonomic nervous system becomes hyperactive, leading to physical signs such as rapid heart rate (tachycardia), high blood pressure (hypertension), profuse sweating, fever, nausea, and tremors. Psychomotor agitation is common, with patients showing restlessness, fidgeting, and sometimes tearfulness or anxiety. Insomnia is also typical, and seizures may occur during this phase, adding to the danger.
The severity of delirium tremens can vary, but it is a medical emergency because the intense autonomic instability can lead to cardiovascular collapse and death if untreated. The risk of DTs is higher in individuals with a long history of heavy drinking, previous episodes of severe withdrawal, or other medical complications.
In summary, delirium tremens is caused by the brain’s sudden withdrawal from alcohol’s depressant effects, leading to an overactive nervous system. This hyperactivity causes severe mental confusion, hallucinations, and dangerous physical symptoms. The condition usually develops within a few days after stopping alcohol and requires immediate medical attention to manage symptoms and prevent fatal outcomes.
