Personal safety: Being under the influence of alcohol and other drugs that lead to intoxication effects personal safety by harming your critical thinking and judgement skills. Depending on the severity of the drug, other common symptoms blackouts, withdrawals, and numbness. All of these things can lead to varying degrees of hospitalization, injury, and death.
Decision making and addiction: Drugs and intoxication affect the mind and the body alike. Decision making is effected by the loss of critical thinking and judgement when intoxicated, and also the inability to speak fluently or make sense. Addiction becomes apparent after the use of a drug, when the user finds themselves craving the drug again or having withdrawals. Both of these things are of great concern, as addiction will start to interfere with the brains ability to process dopamine, the users social life, and their health.
Human body systems: Human body systems are affected by drugs differently depending on what drugs are taken. For example, smoking any drug will effect the lungs. When smoked, carcinogenic compounds are introduced to the respiratory system often leading to cancer. Additionally, chewing tobacco can affect the digestive system. Although the drug is spit out, carcinogenic compounds will still be digested. This will cause esophagus cancer and teeth decay. Lastly, almost all drugs effect the nervous system and the cardiovascular system. Drugs and raise or lower your heartrate, cause terrifying hallucinations, and even paralyze you in the case of ketamine or DXM. And, all of these drugs can lead to addiction, which affects the brain.