What is one psychological effect of steroid use that can manifest as extreme mood fluctuations?

The psychological effect of steroid use that involves extreme mood fluctuations is characterized by mood swings. This refers to significant changes in emotional states, which can manifest as intense irritability, aggression, or euphoria, followed by feelings of depression or sadness. These fluctuations in mood are often attributed to the impact of anabolic steroids on the brain's neurotransmitter systems, which regulate mood and emotions.

In contrast to this, increased emotional stability, consistent mood, and heightened relaxation do not accurately reflect the effects of steroids, as these would imply a calm and steady emotional state, which is not typically associated with steroid use. Instead, users frequently experience unpredictable emotional responses, making mood swings the most accurate answer.