There are many different signs and symptoms that show whether a person is a victim of alcohol and drug abuse.
Some are obvious, others are not.
The one thing that is for sure; they are all signs of trouble.
I will go over the main ones that point to drug and alcohol addiction.

• An alcoholic can easily be detected by the perpetualsmell of alcohol on the concerned person.
  Not too hard there.
  

• Sudden mood swings or temporary changes in behavioralpatterns can usually be associated with an addiction.
  Many times goingwithout drugs or alcohol will cause these behavior problems.
  

• Poor performance in all areas can sometimes beaffiliated with drug and alcohol abuse.
  If they were once good at something, and you see them falling apart, this could be a sign.
  

• Avoidance of older acquaintances can be a majorsymptom in most all drug and alcohol abuse cases.
  They don't want the oldfriend to see what they have become, how they act, or how they look now.
  

• Thefts and other forms of crime can also be a hugetip off in the case of an addiction.
  An addict will steal or break the lawto get whatever they need.
  

When all of these symptoms are combined you know you have got an addict on your hands.
They have most likely lost all control of their actions.
The drug has taken over, and they just cannot make rational decisions for themselves.
Get them some help; they will thank you in the long run.