Altered speech patterns
Stimulants may cause a person to speak quickly and in a somewhat disorganized or unrestrained manner. With depressants, a person may have slow or slurred speech.
Eye and vision changes
Narcotics and opioids can constrict (narrow) the pupils. High doses or overdoses of these can cause pin-point pupils, which do not respond to light.
Other substances like cocaine, hallucinogens, ketamine, and many others will cause dilation may cause pupil dilation (widening) at high doses.
Alcohol intoxication is known to cause blurry vision. Inhalants, solvents, and marijuana may cause eye watering and redness. Meanwhile, those taking meth or amphetamines can experience rapid eye movements known as nystagmus.
Jitters or tremors
Jitters, tremors, or shakiness may be caused by stimulant drugs or long-term substance abuse. It is also a common symptom of withdrawal.
Weight-loss or malnourishment
Over time, an addiction may consume much of a person’s time and energy. They may become so focused on their addiction that they do not eat properly. Money for food may be spent on the addiction instead.
On the other hand, substances like marijuana are known to increase appetite and may cause weight-gain over time.
Behavioral and emotional signs and symptoms of addiction
Insomnia or abnormal sleep patterns
People who have an addiction may lose sleep over it. Additionally, the substance itself may prevent them from sleeping. Trying to stop the addiction can trigger withdrawal symptoms which can also disturb sleep.