NEW YORK -- Like any other golden retriever seeking a treat, Tuesday nudged his owner's hand with his snout one recent morning and waited expectantly.

Luis Carlos Montalvan got up from a chair in his small Brooklyn apartment and walked to the kitchen. Tuesday followed close behind, eyes fixed on a white cabinet. The retriever sat alertly as Mr. Montalvan, an Iraq war veteran with severe post-traumatic stress disorder, reached for a vial of pills, lined a half-dozen on the table and took them one by one.

The dog had gotten what he wanted: When the last pill was swallowed, he got up and followed his master out of the kitchen, tail wagging.

Tuesday is a so-called psychiatric-service dog, a new generation of animals trained to help people whose suffering is not physical, but emotional. They are, effectively, Seeing Eye dogs for the mind.

Tuesday is with Mr. Montalvan at all hours. Taught to recognize changes in a person's breathing, perspiration or scent that can indicate an imminent panic attack, Tuesday can keep Mr. Montalvan buffered from crowds or deliver a calming nuzzle. Other dogs, typically golden retrievers, Labradors or Labrador retriever blends, are trained to wake masters from debilitating nightmares and to help patients differentiate between hallucinations and reality by barking if a real person is nearby.