Paired t-test with PROC MIXED

proc import datafile="C:\projects\Endocrine\CGMS\data\ex\anorexia.csv" out=anorexia 
            dbms=csv replace; getnames=yes;
run;

proc sql;
  create table cbt_long as
  select  var1 as patient, 0 as time, prewt as y 
  from anorexia (where=(treat="CBT"))  
  union
  select  var1 as patient, 1 as time, postwt as y 
  from anorexia (where=(treat="CBT"))  
;quit;

proc mixed data= cbt_long;
  class patient;
  model y = time / s;
  random patient;
*  repeated / subject=patient type=cs rcorr;
run;

/* Paired t-test with SQL */
proc sql;
  select t(postwt-prewt) as t, prt(postwt-prewt) as p_value
  from anorexia (where=(treat="CBT"))  
;quit;