There may be some far reaching implications of drug/alcohol abuse.

If a user is unable to get money to buy drugs/alcohol he/she may turn into stealing.

The adverse effects are just not restricted to the person who is using drugs or alcohol. At times, a drug/alcohol addict becomes the cause of mental and financial distress to his/her entire family and friends.

Those who take drug intravenously (direct injection into the vein using a needle and syringe), are more likely to acquire serious infections like $AIDS$ and Hepatitis $B$.

The viruses, which are responsible for this disease, are transferred from one person to another by sharing of infected needles and syringes.

Both $AIDS$ and Hepatitis $B$ infections are chronic infections and ultimately fatal (death). Both can be transmitted through sexual contact or infected blood.

The use of alcohol during adolescence may also have long term effects; it could lead to heavy drinking in adulthood.

The chronic use of drugs and alcohol damages nervous system and liver (cirrhosis).

The use of drugs and alcohol during pregnancy is also known to adversely affect the foetus.