Lethargy – Causes, Symptoms & Treatment


In medicine, lethargy is a state in which the person concerned is extremely tired and has a greatly increased stimulus threshold. In everyday life, people who appear lazy or tired all the time are also referred to as lethargic. The medically relevant form is a disorder of consciousness.

What is lethargy?

The lethargy essentially consists of a strong tiredness of the affected person as well as an increased stimulus threshold. Accordingly, lethargic people react more slowly (sometimes not at all) to stimuli in their environment. This affects their reaction behavior, their communication behavior and their activities.

They are harder to wake up. In addition, those affected are unable to achieve a normal state of wakefulness for several hours. Rather, they remain in a state of consciousness that can appear as a symptom of various ailments. Lethargy is not an independent disease, but always a symptom of another ailment.


Lethargy is caused by a wide range of diseases and conditions that primarily affect the brain . Lethargy is a major symptom of European sleeping sickness (a form of encephalitis that occurs only rarely).

Any disease or condition that increases intracranial pressure can also trigger lethargy. The main ones to be mentioned here are masses in the brain ( tumours and edemas ) and extreme high blood pressure . Metabolic diseases and diseases that change the blood count can also be the cause of increased intracranial pressure. Heart failure can also lead to changes in pressure in the brain.

Psychological conditions can also lead to lethargy. For example, it is one of the most common symptoms of depression . Sleep deprivation, breathing problems while sleeping, alcoholism , cardiac arrhythmia , and medications with sedating effects can also lead to lethargy. The lethargy as a disturbance of consciousness is described as tiring and increasing the stimulus threshold.

When considering states of fatigue (due to sleep deprivation), however, people who are very tired but have a greatly reduced stimulus threshold are sometimes referred to as lethargic. These individuals are thus easily irritable and yet, by some considerations, are considered lethargic.

The colloquial meanings of lethargic and lethargy should be left out at this point.

Symptoms, Ailments & Signs

The lethargy is characterized above all by the fact that those affected have a greatly increased need for sleep . This is also present during the day, forcing people to rest at times.

However, most lethargic people do not manage to get into the deep sleep phase and accordingly cannot recover despite sleep. As a result, those affected become more sluggish in their entire behavior. They miss the details. Spoken words and calls to action often slip past them. Dozing states often seem to be initiated without any specific trigger. Lethargic people are also more difficult to wake up, but still don’t sleep deeply or well.

Lethargic people can appear listless in different ways. The transition to apathy is correspondingly fluid and difficult to define. People are unable to concentrate. Blood pressure may be elevated . The eyes can become hypersensitive.

A form of lethargy, which is primarily triggered by sleep problems , on the other hand, greatly reduces the stimulus threshold, with the person concerned complaining primarily of tiredness. However, this condition is temporary – contrary to real lethargy – and usually resolves with the next sleep in. These lethargic people are often highly irritable and have an increased need to withdraw.

As a condition, lethargy usually develops over a period of time. Depending on the cause, this is then organic or psychological. At a certain point, the body is so overloaded that the person becomes lethargic. Early signs of lethargy are tiredness despite the feeling of having had enough sleep, as well as increased inattention.


Lethargy as a condition itself complicates the sufferer’s personal life in particular. For example, lethargic people are not sufficiently productive. Social isolation can occur and is often caused by increasing apathy. In addition, the risk of an accident increases enormously with increasing fatigue. Lethargy as a disorder of consciousness knows no real increases. Rather, it has an indirect effect through possible complications.

Overall, however, the causes of the lethargy are more decisive for the consideration of possible complications. In the worst case, untreated depression can lead to self-harm and suicidal behavior. Brain tumors and other damage to brain tissue are often associated with a high mortality rate. Heart damage and nocturnal breathing problems can be the harbingers of serious and chronic ailments. Alcoholism as a cause can ultimately be fatal.

Another problem with the combination of depression and lethargy is that depression often remains untreated for a long time and lethargy often appears very early. In addition, feelings of guilt, which arise because of the non-performed (but expected) performance, intensify the depression. The losses that lethargic people suffer as a result of their social and general performance sometimes appear very early.

In general, the risk of complications affecting the personal life of the lethargic increases with the length of time the patient goes untreated. The same applies to complications caused by the triggers of lethargy.

When should you go to the doctor?

Lethargy that seems causeless and lasts more than a few days is always a reason to see a doctor. The person concerned will notice a strong and inexplicable tiredness. Accordingly, symptoms of lethargy that occur after a bad night are no reason to seek medical attention.

Initial attempts can be made at the family doctor . Depending on what the causal research reveals, it must then be referred to a specialist. For example , cardiologists , neurologists and doctors with a psychiatric orientation are eligible.


A doctor usually determines whether a person is lethargic by taking a medical history. It is important to find out whether the condition can be explained by the living conditions or whether it has a disease value. If the latter turns out to be the case, various causes must be considered.

For this purpose, the mental and physical health of the patient is considered. An examination of the brain using imaging methods is usually at the end of the search for the causes of lethargy. Occasionally, no clear diagnosis can be made. A psychological cause is then usually assumed and action taken accordingly.

In addition, other diseases and conditions with similar symptoms must be ruled out for an accurate diagnosis. These include, for example, somnolence or drowsiness as a result of an accident.

Treatment & Therapy

If the triggers are organic and known, the treatment of lethargy is ideally causal. This means that possible triggers of lethargy, which can be pinned down, for example, in the heart or in the brain, are treated. Due to the amount of ailments in question here, there are many treatment methods. They can be medical and surgical.

Brain tumors and cerebral edema often require complicated interventions in and on the brain. If heart failure is the cause, treatment usually consists of medication and a change in lifestyle. Increased intracranial pressure must be considered on a case-by-case basis.

If, on the other hand, psychological triggers for lethargy are known or suspected, various psychotropic drugs are used. In most cases, these are drugs that are supposed to have a stimulating and motivating effect. In the case of depression, antidepressants (usually SSRI reuptake inhibitors) are prescribed as standard, which at the same time have a positive effect on lethargy.

Otherwise, lethargy can be treated with methylphenidate and other psychostimulants. Depression also requires other treatment methods, such as talk therapy or the formulation and achievement of new goals.

If the patient’s sleep is the main problem, methods from the field of sleep hygiene are used to try to enable better sleep. This means that the patient’s sleep is analyzed and then ways are shown to improve their sleep. This can affect sleeping arrangements, lighting and much more.

Outlook & Forecast

The prognosis for lethargy depends on the underlying disease. It is not an independent disease in which a prospect of the further course of the disease is given. Rather, the severe tiredness and low physical and mental performance is a symptom. Therefore, the clarification and elimination of the cause is absolutely necessary in order to be able to give further assessments.

In most cases, the patients suffer from an underlying mental illness. They include depression or burnout . The disorders are characterized by a mostly protracted course of the disease. Still, there is a chance of a cure. If a chronic disease is present, the overall prognosis is usually unfavorable. The existing state of health is often maintained over a long period of time or deteriorates continuously. If the person affected manages to recover from the main illness in cooperation with a therapist and with their own cooperation, the symptoms of lethargy are usually relieved as well.

If physical disorders are present, medication is usually required to improve health. There is a long-term treatment, which usually involves irreparable disorders of the heart, the circulatory system or the metabolism. Without medical help, a good prognosis is rarely possible. The diseases that lead symptomatically to lethargy are too extensive and complex.


As varied as the causes of lethargy are, so are the measures to prevent the condition. The heart and brain, for example, can be well protected by an overall healthy lifestyle. Nevertheless, the risk of developing a brain tumor, for example, cannot be completely avoided.

However, each individual can eliminate risk factors. Depression can only be prevented to a limited extent. They can theoretically affect anyone and people have different susceptibility to it. However, there is evidence that the risk of depression can be reduced by getting enough serotonin and dopamine. Both are linked to the day-night rhythm and to sufficient supplies of sunlight. Accordingly, a healthy and regular sleep and enough activities during the day can be beneficial.

Preventing problems falling asleep and staying asleep is also a way to prevent lethargy. This looks different for every person. For example, some people sleep better if they eat their last meal a few hours before, and others sleep better if they do light exercise before bed. Everyone has to find out for themselves what has a beneficial effect on their own sleep.


In most cases, those affected by this disease have no follow-up care available. The disease itself must first and foremost be examined and treated directly by a doctor so that there are no further complications that can further complicate the everyday life of the person affected. The person affected should consult a doctor at the first sign of this disease so that it can be treated quickly.

If the disease is left untreated, it can lead to serious complications that significantly reduce the quality of life of those affected. In most cases, patients with lethargy need treatment from a psychologist. The treatment should be carried out regularly in order to properly alleviate the symptoms. Contact with other patients with the same disease can also be useful, as this leads to an exchange of information. As a rule, life expectancy is not reduced by this disease.

You can do that yourself

The options for self-help in the case of lethargy largely correspond to the self-help measures that are also recommended for the underlying diseases.

Furthermore, lethargic episodes can be cushioned by planned rest and sleep breaks, which ideally are integrated into everyday life. The fundamentally lack of motivation and powerlessness, on the other hand, can hardly be overcome without outside help. Recourse to supposedly stimulating drugs is not advisable.

If the person concerned has learned relaxation methods, such as autogenic training, he can also use these. Since it is not possible for most lethargy sufferers to enter the deep sleep phase, more sleep is not a sensible self-help option. Overall, the possibilities for self-help to counteract the causes of lethargy are limited.

Website | + posts

Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.