Euphoria and Illusion: Drugs would distort the normal perception capacity and functionality of the brain resulting in hallucination by creating a false appearance to make one feel dreamy, high or satisfied synthetically.

Stress: Drugs would give one a perception that it is helping to ease and solve the problems that causes stress. However, this is not so in reality. Using drugs in the long run can result in detrimental effects and change the way the brain works, causing an elevation in the level of stress and anxiety.

Mental illnesses: Drug abuse is more commonly seen amongst people suffering from chronic psychological illnesses. It is proven that schizophrenia could result due to usage of drugs. However, more research and studies are needed to conclude that mental illnesses could arise due to serious drug usage. 

The action of the abuser may be affected due to these psychological effects of drug abuse which could result in people around them suffering from the consequences of it.