Cause | Common Features* | Tests |
---|---|---|
Mental disorders | ||
Symptoms that occur in episodes lasting a few weeks to a few months and that include mania, depression, or both Episodes of mania:
Episodes of depression:
| A doctor's examination | |
Episodes of depression as described in bipolar disorder (see above) without a history of mania | A doctor's examination | |
Usually symptoms that develop slowly, at first with mildly disorganized thinking and difficulty coping with daily routines Later symptoms:
| A doctor's examination | |
Drugs | ||
Use of a drug, particularly | Agitation and sometimes panic or aggression Sometimes hallucinations With long-term use of alcohol:
With long-term use of amphetamines:
With short-term excessive use of amphetamines or cocaine:
| A doctor's examination Sometimes blood or urine tests to detect the drug Sometimes EEG Electroencephalography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more (which records the brain’s electrical activity) |
Withdrawal of a drug, particularly | Typically significant confusion and delirium Shaking (tremors), headache, sweating, fever, and a rapid heart rate or palpitations Sometimes seizures, hallucinations, and sleep disturbances Onset after cutting down or stopping the drug | A doctor's examination Sometimes blood or urine tests to detect drugs |
Side effects of a drug | Vary, depending on the drug Drugs with anticholinergic effects, such as
| A doctor's examination Sometimes stopping the drug to see whether the symptom goes away |
Brain disorders | ||
Symptoms that progress slowly Loss of short-term memory, difficulty finding the right words, and poor judgment Difficulty with daily activities (such as balancing a checkbook or finding their way around their neighborhood) Usually in people over 60 | A doctor's examination Often CT Computed Tomography (CT) Computed tomography (CT) is a type of medical imaging that combines a series of x-rays to create cross-sectional, detailed images of internal structures. In computed tomography (CT), which used... read more , MRI Magnetic Resonance Imaging (MRI) Magnetic resonance imaging (MRI) is a type of medical imaging that uses a strong magnetic field and very high frequency radio waves to produce highly detailed images. During an MRI, a computer... read more , or PET Positron Emission Tomography (PET) Positron emission tomography (PET) is a type of medical imaging called radionuclide scanning. By detecting radiation after a radioactive material is administered, PET creates images that can... read more of the brain Detailed testing of mental function involving a series of questions and tasks (neuropsychologic testing) | |
Brain infections such as | Headache Usually confusion and fever Pain and/or stiffness when the doctor bends the neck forward (more common in people with meningitis) With herpes simplex encephalitis, hallucinations of bad odors and sometimes seizures | A spinal tap (lumbar puncture) Often CT or MRI of the brain Culture of samples of blood, urine, and material from the throat |
Forgetfulness and headaches Emotional instability in the weeks after a significant head injury | CT or MRI of the brain Testing of IQ and executive functions such as the ability to plan and solve problems (neurocognitive testing) | |
Brain tumors Overview of Brain Tumors A brain tumor can be a noncancerous (benign) or cancerous (malignant) growth in the brain. It may originate in the brain or have spread (metastasized) to the brain from another part of the body... read more or bleeding in the brain Overview of Hemorrhagic Stroke Hemorrhagic strokes include bleeding within the brain (intracerebral hemorrhage) and bleeding between the inner and outer layers of the tissue covering the brain (subarachnoid hemorrhage). ... read more (brain hemorrhage) | With brain tumors, a headache that develops gradually and is often worse during the night or early morning and when lying flat With hemorrhage, a headache that starts suddenly (called a thunderclap headache) Often confusion and drowsiness Sometimes seizures | CT or MRI of the brain |
Weakness and/or numbness that comes and goes in different parts of the body Sometimes partial loss of vision or double vision Sometimes symptoms that are worsened by heat (such as a warm bath or hot weather) | MRI of the brain and spinal cord Sometimes a spinal tap Spinal Tap Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more Nerve conduction studies Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more (measuring how fast nerves transmit signals) and electromyography (stimulating muscles and recording their electrical activity) | |
Tremors of the hands and fingers while they are at rest Stiffness and difficulty moving and maintaining balance Slowed speech and limited facial expressions | A doctor's examination | |
Seizure disorders (typically complex partial seizures Focal-onset seizures ) | Episodes of abnormal behavior Usually confusion and staring Sometimes involuntary chewing, smacking of the lips, and purposeless movements of the limbs Typically no loss of consciousness and no general shaking of the body (convulsions) Sometimes hallucinations of odor or taste | MRI of the brain EEG |
Symptoms that appear suddenly Usually weakness or paralysis on one side of the body and unsteadiness when walking | CT or MRI of the brain | |
Bodywide (systemic) disorders | ||
Weakness, sweating, and confusion Almost always in people taking drugs for diabetes | Tests to measure the blood sugar (glucose) level | |
Swelling of the legs, loss of appetite, and nausea Weakness that typically develops over several weeks | Blood and urine tests to evaluate how well the kidneys are functioning | |
Yellow color of the skin and/or whites of the eyes (jaundice) Usually swelling of legs and/or abdomen A reddish purple rash of tiny dots (petechiae) Usually in people already known to have a liver disorder | Blood tests to evaluate how well the liver is functioning (liver tests) | |
Usually painful, swollen joints Often a rash, particularly on the face or areas exposed to sunlight Sometimes a headache | Blood tests to check for certain antibodies | |
Thyroid disorders, including | Typically in hyperthyroidism: Palpitations, excessive sweating, difficulty tolerating heat, an increased appetite, weight loss, shakiness (tremor), and sometimes bulging eyes Typically in hypothyroidism: Fatigue, constipation, difficulty tolerating cold, decreased appetite, weight gain, slow speech, sluggishness, a puffy face, drooping eyelids, coarse and thick dry skin, and loss of eyebrow hair | Blood tests to evaluate how well the thyroid gland is functioning |
Vitamin deficiency, such as deficiency of thiamine Thiamin Deficiency Thiamin deficiency (causing beriberi and other problems) is most common among people whose diet mainly consists of white rice or highly processed carbohydrates in countries with high rates of... read more or vitamin B12 Vitamin B12 Deficiency Vitamin B12 deficiency can occur in vegans who do not take supplements or as a result of an absorption disorder. Anemia develops, causing paleness, weakness, fatigue, and, if severe, shortness... read more | Disorientation, an impaired memory, and irritability Abnormal sensations in the hands and feet Other symptoms, depending on which vitamin is deficient | Blood tests to measure vitamin levels |
* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. | ||
CT = computed tomography; EEG = electroencephalography; IQ = intelligence quotient; MRI = magnetic resonance imaging; PET = positron emission tomography. |