Sort of. Preparing to commit suicide by drug overdose, Ben leaves his beloved dog in a car and puts a note on the windshield giving the dog's name and an emergency contact phone number (that of Ben's mother).
Causes and effects of drug addiction shown and discussed in detail throughout the movie. A major character and many minor characters are addicted to drugs.
Drug abuse, overdosing, etc is discussed frequently. Very brief, dark shot of a man injecting himself. Drugs (in packet form) handled but not used on screen. Smoking/vaping on screen.
Ben and his mom "visit one of Ben's former high school teachers whom Holly is shocked to learn used to provide her son with drugs in exchange for sexual favors." (source: Wikipedia) It is never said outright, but it is heavily implied.