boy, kid nibbles and bites a nail on his hand, close-up, the concept of psychological disorder, stress, bad childhood habits

boy kid nibbles bites nail his hand close concept psychological disorder stress bad childhood habits habit bite nails hygiene upset nervous tension aggression hands mental hyperactivity anxiety syndrome attention deficit worms germs burrs obsessive compulsive manicure psychology obsessivecompulsive test face abuse stop sad expression terror stressed scared lost fingernail unhappy pressure stressful nerve finger scarey biting