- Psychasthenia 300.89
- Psychiatric disorder or problem NEC 300.9
- Psychogenic - see also condition
- Psychoneurosis, psychoneurotic (see also Neurosis) 300.9
- Psychopathic - see also condition
- Psychopathy, sexual (see also Deviation, sexual) 302.9
- Psychophysiologic, psychophysiological condition - see Reaction, psychophysiologic
- Psychose passionelle 297.8
- Psychosexual identity disorder 302.6
- Psychosis 298.9
- Psychotic (see also condition) 298.9
- Pterygium (eye) 372.40
- Ptilosis 374.55
- PTLD (post-transplant lymphoproliferative disorder) 238.77
- Ptomaine (poisoning) (see also Poisoning, food) 005.9
- Ptosis (adiposa) 374.30
- PTSD (Post-Traumatic Stress Disorder) 309.81
- Ptyalism 527.7
- Ptyalolithiasis 527.5
- Pubalgia 848.8
- Pubarche, precocious 259.1
- Pubertas praecox 259.1
