A drug is a chemical or natural substance that changes the way our body work. According of WHO, “A drug is any substance which, when taken into the body, alters its function physically and/or psychologically, excluding food and water. Drug can be legal and illegal, medical and non-medical.

Drug Abuse is "the use of illicit drugs or the abuse of prescription or over-the-counter drugs for purposes other than those for which they are indicated or in a manner or in quantities other than directed."

Drug Dependence: It is defined as “compulsively seeking to use a substance, regardless of the potentially negative social, psychological and physical consequences.” Substance abuse leads to substance dependence with the development of tolerance and withdrawal. Tolerance: It is a defined as a need for increased amount of substance to achieve intoxication or desired effect.

Withdrawal Symptoms: occur when the user who is dependent on a substance stops using it. Withdrawal symptoms range from mild tremors to convulsions, severe agitation and sometimes death. Withdrawal symptoms vary depending upon the substance abused, duration of the use of substance and the quantity abused.

Diminished or extinguished sense of smell and taste Smoker's cough Gastric ulcers Chronic bronchitis Increase in heart rate and blood pressure Premature and more abundant face wrinkles Heart disease Stroke Cancer

Effects of Alcohol Abuse Short-term effects  Distorted vision, hearing, & coordination  Altered perceptions and emotions  Impaired judgment  Bad breath  Hangovers Long-term effects  Loss of appetite  Vitamin deficiencies  Stomach ailments  Skin problems  Sexual impotence  Liver damage  Heart & central nervous system damage  Memory loss

Personal factors Beliefs and perceptions about the benefits of substance use Lack of knowledge of consequences Feeling of enhanced self-efficacy Personality factors, e.g., depression, low self-esteem False psychological well-being

Behavioural factors Teenagers tend to be heavy and frequent users of substances compared with adults. Teenagers often use more than one substance. Academic achievement (statistically, low achievement = higher risk). Teenagers tend to engage in more high-risk behaviours than adults. Teenagers may lack well-developed self- control and may behave more impulsively than adults. Teenagers out of curiosity experiment.

Environmental factors Attitudes and values of parents and peers in support of substance use. Parental, sibling and peer use of substances Advertising or media glamorization of substances Easy accessibility of substances Social and cultural norms accepting substance use Factors such low socio-economic status are statistically related to the tendency to use substances. Physiological factors Developing brains and bodies are more sensitive to drugs.

Individual: High self-esteem; high intelligence; optimistic about future; coping skills; belief in self, expectations, norms & values. Family: Strong parent & youth attachment; consistent discipline & supervision; no family history of substance abuse. Peer group: Non-substance abusers; have conventional values & shared interests. Schools: Connectedness; quality school with opportunity to succeed. Community and Society: Health, support & recreational facilities; safe neighbourhood; connectedness to culture, religion etc.