A U.S. Navy officer stationed in Hawaii said in a lawsuit that he can’t get a gun permit because he saw a therapist one time for feeling depressed and homesick.

Michael Santucci’s lawsuit is the latest challenge to Hawaii’s gun ownership restrictions. His lawsuit focuses on a state law that allows access to an applicant’s medical records in determining whether someone should be allowed to own a gun, which his lawyers say is unique to Hawaii.

Santucci, a cryptologic warfare officer from Fort Myers, Fla., saw a medical provider at a military hospital for feelings of depression and homesickness a few months after arriving in Hawaii last year, according to his lawsuit, filed Sunday. He wasn’t diagnosed with any behavioral, emotional or mental disorder, the lawsuit said.

When he later filled out forms to register his firearms with the Honolulu Police Department, he indicated he had been treated for depression but noted it was “not serious.”

Hawaii law requires registration of all firearms. Prior to acquiring a gun, an applicant must apply for a permit. When applying, the applicant signs a waiver allowing the chief of police of the county issuing the permit access to any records that have a bearing on the mental health of an applicant, the lawsuit said.

Santucci received a letter from HPD saying that in order to process his application, he needs written certification from a psychologist or doctor documenting he’s no longer affected by any mental disorder, the lawsuit said. Governmental physicians, such as Department of Defense personnel, are forbidden from writing such statements, his lawyers said.

The lawsuit noted the Navy approves of Santucci possessing firearms.

Alan Beck, one of Santucci’s attorneys, said it’s unconstitutional to require a medical evaluation to exercise a fundamental right when there’s no evidence of mental illness. “We’re challenging the process,” Beck said.

A spokesperson for the state attorney general’s office declined to comment Wednesday because they had not yet been formally served with the complaint.

Representatives for the City and County of Honolulu, also named as a defendant, didn’t immediately respond to a message seeking comment.

“As a practical matter, the City makes the applicant disprove a negative — I am not incompetent — which is expensive and burdensome especially considering that virtually all Hawaii doctors refuse to write the waivers the City requires as proof of mental competency,” Santucci’s lawyers said in a motion for a preliminary injunction.