A Nassau County jury Wednesday rejected a defendant’s claim that withdrawal from the antidepressant Zoloft had driven him to beat up his girlfriend.

After deliberating for three hours, the jurors found Brandon Hampson, 39, guilty of third-degree assault, a misdemeanor. Hampson also was found guilty of third-degree attempted assault and second-degree harassment, but acquitted of menacing and unlawful imprisonment charges by the panel of three men and two women.