Texas Government Code - GOV'T § 839.201. Eligibility for Disability Retirement Annuity

(a) A member, other than a member who is eligible to receive a service retirement annuity under Section 839.101 or a cash balance annuity under Section 840A.052, is eligible, regardless of age, to retire from regular active service for disability and receive a disability retirement annuity if the member has at least seven years of service credit in the retirement system.

(b) A member otherwise eligible may not receive a disability retirement annuity if the member is an active judge, as defined by Section 74.041.

(c) A disability retirement annuity may be denied on the ground that a claimed physical incapacity is caused by or results from an intemperate use of alcohol or narcotic drugs.