Yes, drugs can cause anxiety as a side effect. Different drugs have different mechanisms of action in the brain and can affect anxiety levels in different ways. For example, stimulant drugs such as cocaine and amphetamines can increase anxiety by activating the sympathetic nervous system and increasing heart rate and blood pressure. On the other hand, sedative drugs such as benzodiazepines and alcohol can have an anxiolytic effect and reduce anxiety in the short term, but may lead to rebound anxiety when the drug wears off or during withdrawal. Additionally, chronic drug use and addiction can cause or worsen anxiety disorders.