- Magnetic resonance imaging
- Major depressive disorder
- Male orgasmic disorder
- Malingering
- Managed care
- Manic episode
- Maprotiline
- Marital and family therapists
- Mathematics disorder
- Medication-induced movement disorders
- Meditation
- Mental retardation
- Mesoridazine
- Methadone
- Methylphenidate
- Mini-mental state examination
- Minnesota Multiphasic Personality Inventory
- Mirtazapine
- Mixed episode
- Mixed receptive-expressive language disorder
- Modeling
- Molindone
- Movement disorders
- Multisystemic therapy
