- Safe Drinking Water and Toxic Enforcement Act
- Salvia divinorum
- SAMHSA
- SAMHSA’s 24-Hour Helpline
- SAMHSA’s National Clearinghouse for Alcohol and Drug Information
- Sanorex
- Schedule I controlled substance
- Schedule II controlled substance
- Schedule III controlled substance
- Schedule V controlled substance
- Schizoid personality disorder
- Schizophrenia
- Schizotypal personality disorder
- Second Chance Act
- Sedation
- Sedative
- Seizures
- Selective serotonin reuptake inhibitors
- Self-help groups
- Self-medication
- Sensorimotor psychotherapy
- Serotonin
- Sertraline
- Sex Addicts Anonymous (SAA)
- Sex and Love Addicts Anonymous (SLAA)
- Sex therapy
- Sexaholics Anonymous (SA)
- Sexual addiction
- Sexual Recovery Anonymous (SRA)
- Shopping addiction
- Side effects
- Sin tax
- Single Convention on Narcotic Drugs
- Skittling
- Skunk
- SMART Recovery®
- SNRI
- Sober / sobriety
- Sober coaches
- Sober living house
- Social anxiety disorder
- Solution-focused brief therapy
- Soma
- Somatic experiencing
- Speed
- Speedballs
- Spenders Anonymous
- Spice
- Sponsor
- Stanozolol
- Steroids (Anabolic)
- Stimulants
- Street drug
- Stress
- Stress coping mechanisms
- Stress inoculation training
- Stress management
- Sublimaze
- Suboxone
- Substance abuse
- Substance abuse disorders
- Substance abuse treatment
- Substance abuse treatment facility locator
- Substance use disorders
- Subutex
- Suicidal ideation
- Suicide
- Support group
- Supportive psychotherapy
- Synthetic heroin
- Synthetic marijuana