Most Abused Substances
1. Alcohol (ethyl) – considered as the #1 abused substance in America, with more than half the American population or around 135.5 million recognized as drinkers and around 86 million identified as abusers.
Acute Effects – drowsiness, slurred speech, nausea, emotional volatility, loss of coordination, visual distortions, impaired memory, sexual dysfunction, loss of consciousness

2. Nicotine – there is an estimated 69.5 million Americans over the age 12 who were users of tobacco.
Acute effects – increased blood pressure and heart rate

3. Canabinoids (Marijuana, Hashish) – most commonly used illicit drug with a reported 18.9 million users in the U.S. alone.
Acute Effects – Euphoria; relaxation; slowed reaction time; distorted sensory perception; impaired balance and coordination; increased heart rate and appetite; impaired learning, memory; anxiety; panic attacks; psychosis

4. Opioids (Heroin) – considered as the most addictive substance in the world, whose users has increased to over 669,000.
Acute Effects – Euphoria; drowsiness; impaired coordination; dizziness; confusion; nausea; sedation; feeling of heaviness in the body; slowed or arrested breathing

5. Stimulants (Cocaine, Ampethamine) – there is a reported 1.6 million Americans who are dependent on cocaine.
Acute Effects – Increased heart rate, blood pressure, body temperature, metabolism; feelings of exhilaration; increased energy, mental alertness; tremors; reduced appetite; irritability; anxiety; panic; paranoia; violent behavior; psychosis

6. Club Drugs (MDMA [Methylene-dioxy-methamph-etamine], Flunitrazepam, GHB) – the effects of methampethamine can last 40 times longer than cocaine. It has a reported 440,000 users in America.
Acute Effects – Mild hallucinogenic effects; increased tactile sensitivity; empathic feelings; lowered inhibition; anxiety; chills; sweating; teeth clenching; muscle cramping

7. Hallucinogen s (LSD, Mescaline, Psilocybin) – There is a reported 1.1 million people who use hallucinogens.
Acute Effects – Altered states of perception and feeling; hallucinations; nausea; Increased body temperature, heart rate, blood pressure; loss of appetite; sweating; sleeplessness; numbness, dizziness, weakness, tremors; impulsive behavior; rapid shifts in emotion

8. Sedatives (benzodiazepines and tranquilizers) – There is a reported 2.4 million users of sedatives. They are commonly prescribed as depressants.
Acute Effects – Stimulation; loss of inhibition; headache; nausea or vomiting; slurred speech; loss of motor coordination

Sources: and duffysrehab