The duration of any kind of addiction treatment is dependent upon the condition of the client, the type of addiction they are suffering from, and the severity of the effects of substance abuse. The treatment can be an outpatient treatment program or an inpatient one. When it’s the latter, the treatment can last as short as 28 days or as long as 120 days to a year. After graduating from rehab, there are also aftercare programs offered to help the client keep their sobriety. These aftercare services will vary depending on the treatment facility and on the needs of the client.