subchronic
/ˌsʌbˈkrɒnɪk/adjective
1 Medicine. Of a disease, symptom, etc.: intermediate between acute and chronic; more chronic than acute; (in later use) specifically (of schizophrenia) having a duration which is greater than six months but less than two years.
2Chiefly Pharmacology. Of an experimental study: having a fairly long duration (typically between one and three months).
Origin
Mid 19th century; earliest use found in The London Medical Gazette. From sub- + chronic.