Watery eyes and yawning indicate withdrawal symptoms of which substance?

Watery eyes and yawning are commonly associated with withdrawal symptoms from opioid substances, such as heroin. When a person becomes dependent on opioids, the body adapts to their presence. Upon cessation of use, the body must adjust back to functioning without the drug, leading to various withdrawal symptoms.

These symptoms can include anxiety, restlessness, muscle aches, insomnia, and particularly, physical signs like watery eyes and increased yawning. This is because opioids affect the body's systems that regulate pain, mood, and pleasure, and when they are removed, the physiological responses can manifest in visible ways, such as increased lacrimation (tear production) and yawning.

The other substances mentioned, while they may have their own withdrawal symptoms, typically do not present with watery eyes and yawning as key indicators. Barbiturates might lead to various withdrawal symptoms such as anxiety or seizures, stimulants often lead to fatigue and depression, and cocaine withdrawal likewise includes fatigue but not commonly watery eyes or yawning. Therefore, heroin is the substance that most accurately aligns with the symptoms of watery eyes and yawning during withdrawal.