Final answer:
The patient's symptoms and lab findings suggest anabolic steroid abuse, which can cause increased aggression, cardiovascular problems, liver damage, and hormonal imbalances.
Step-by-step explanation:
The 21-year-old man presenting with irritability and aggressive behavior, who is a college football linebacker in training, has an elevated BP, mild gynecomastia, increased hematocrit, and normal pulse. These symptoms and lab findings are suggestive of anabolic steroid abuse, which can cause erythocytosis, hepatoxicity, and dyslipidemia. Anabolic steroids are synthetic variations of the male sex hormone testosterone and can lead to various health problems when misused.
Anabolic steroid abuse is known to cause several side effects, including increased aggression ('roid-rage') and mood disturbances. Moreover, anabolic steroids can lead to cardiovascular issues, liver damage, hormonal imbalances, and alterations in physical appearance. In athletes, the abuse of anabolic steroids is prohibited due to both health risks and unfair advantages in performance.