An alteration in mental status refers to general changes in brain function, such as confusion, amnesia (memory loss), loss of alertness, disorientation (not cognizant of self, time, or place), defects in judgment or thought, unusual or strange behavior, poor regulation of emotions, and disruptions in perception, psychomotor skills, and behavior. While an altered mental status is obviously characteristic of a number of psychiatric and emotional conditions, medical conditions and injuries that cause damage to the brain, including alcohol or drug overdose and withdrawal syndromes, can also cause mental status changes. Confusion, lethargy, delirium, dementia, encephalopathy, and organic brain syndrome are all terms that have been used to refer to conditions hallmarked by mental status changes. 

Related Symptoms & Signs 

Confusion 

Paranoia 

Memory Loss 

Other causes of altered mental status 

Brain Infections/Abscesses 

Decompression Sickness 

Drug Overdose 

High Altitude Cerebral Edema 

Infection of the Brain or CNS 

Korsakoff Syndrome 

Lipid Storage Diseases 

Liver Failure 

Medications 

Poisoning 

Respiratory Failure 

Severe Hemorrhage 

Thyroid Storm 

Toxins 

Vascular Dementia 

Wernicke Syndrome 

Wilson Disease 

Withdrawal From Drug or Alcohol Dependence 

 Source: https://www.medicinenet.com/altered_mental_status/symptoms.htm