How do you recognize a smart person?
interesting that you didn't ask; how do you recognize an intelligent person? a smart person knows how to use their intelligence in sane and healthy ways; to solve problems, be creative, have relationships, adapt to new or unknown realities, situations, and contexts, the list goes on. -----I like Gabriel's answer about the "street smarts" of the Native Americans.
Is there a hadith or ayat regarding people with mental disorders?
20.124: "And whoever turns away from My remembrance (Quran) - indeed, he will have a depressed life, and We will gather him on the Day of Resurrection blind." 70.19: "Indeed, mankind was created anxious " 46.13: "Indeed, those who have said, "Our Lord is Allah ," and then remained on a right course - there will be no fear concerning them, nor will they grieve. " 10.57: "O mankind! there hath come to you a direction from your Lord and a healing for the (diseases) in your hearts,(Quran)- and for those who believe, a guidance and a Mercy. " 2.275: " Those who consume interest cannot stand [on the Day of Resurrection] except as one stands who is being beaten by Satan into insanity. That is because they say, "Trade is [just] like interest." But Allah has permitted trade and has forbidden interest. So whoever has received an admonition from his Lord and desists may have what is past, and his affair rests with Allah . But whoever returns to [dealing in interest or usury] - those are the companions of the Fire; they will abide eternally therein." 54.47: "Indeed, the criminals are in error and madness. " 16:53. " And ye have no good thing but is from Allah: and moreover, when ye are touched by distress, unto Him ye cry with groans;" 28.83: "And (remember) Ayub (Job), when he cried to his Lord: "Verily, distress has seized me, and You are the Most Merciful of all those who show mercy." 27:62. "Or, Who listens to the (soul) distressed when it calls on Him, and Who relieves its suffering, and makes you (mankind) inheritors of the earth? (Can there be another) god besides Allah? Little it is that ye heed "