Gibbs acknowledges that he is a "former marine." Unlike other services, marines never consider themselves "former," even after leaving active duty. The question would never have been asked by a marine, and Gibbs would have bristled at it in any case.
Police Chief Whalen tells Gibbs that according to Emmy Poole's mother she had been suffering from depression for the last few years as they look into her medicine cabinet. All the medications are for treating moderate pain and prescribed by a dentist. There were no antidepressants or anti-anxiety medications visible in the cabinet.