As of September of 2015 NH law provides limited protection for medical marijuana patients who are not NH residents, but travel through, or to New Hampshire.
RSA 126-X:2 prohibits the arrest and prosecution of “qualifying patients” who possess two ounces or less of useable cannabis.
To be a “qualifying patient” a person must either be a New Hampshire resident who has a valid card issued pursuant to RSA 126-X:4, or he must be a patient with a valid registry identification card, or its equivalent, issue by another state, district, territory, or commonwealth. He must also have, in his possession, a statement from his provider stating he has a qualified medical condition recognized by New Hampshire law.
RSA 126-X:1(IX) lists various qualifying medical conditions. These include cancer, glaucoma, various terminal conditions, and some debilitating injuries. PTSD is not a listed qualifying medical condition in New Hampshire even though it is a medical condition that qualifies in many other states.
If you are a medical marijuana patient from out of state traveling to or through New Hampshire you should: (1) bring a copy of your valid identification card; (2) bring a statement form your health care provider specifically listing your qualifying condition (make sure it is a condition recognized in New Hampshire by clicking this link); (3) make sure you possess less than two ounces; and (4) make sure not to use your cannabis for any reason other than treating your qualified condition.