In accordance with Ohio Revised Code:
Psychologists are required to keep records for at least 5 years [this is now six according to HIPAA] post-termination of services and then the "general record" or "summary thereof" for an additional 7 years.  The rules do not specify what "general" or "summary" actually mean in practice, so this is ultimately up to the licensee.  Some psychologists keep the entire record for 12 years post-termination to avoid decisions about what to retain and what to destroy after the 5 year mark.

The requirement is in OAC 4732-17-01 (B) Negligence:

(6) Maintenance and retention of records.
(a) A psychologist or school psychologist rendering professional individual services to a client, or services billed to a third-party payer, shall maintain a professional record that includes:
(i) The presenting problem(s),
(ii) The date(s) and purpose, if not self-evident, of each service contact,
(iii) The fee arrangement,
(iv) Any test or other evaluative results obtained,
(v) Test data,
(vi) A copy of any test or other evaluative reports prepared as part of the professional relationship,
(vii) Notation and results of formal contacts with other providers, and
(viii) Authorizations, if any, by the client for release of records or information.
(b) To meet the requirements of these rules, but not necessarily for other legal purposes, the psychologist or school psychologist shall ensure that each data entry in the professional record is maintained for a period of not less than five years after the last date of service rendered, or not less than the length of time required by other regulations if that is longer. The general record or a summary thereof shall be kept for a period of not less than twelve years after the last date of service rendered.
(c) A psychologist or school psychologist shall store and dispose of written, electronic, and other records of clients in such a manner as to ensure their confidentiality. Each licensee shall report to the board on the biennial registration (renewal) form the name and telephone number of the person knowledgeable about responsibility for records in the event of the licensee's absence, emergency or death.
(d) In the event a complaint has been filed, a psychologist or school psychologist shall provide the original or a full copy of the client file or other client-identifiable documents to the board upon request, provided that the request is accompanied by a copy of a release signed by the client.