data initial; infile "e:\anti\antiread.dat";
 input anti1 anti2 anti3 anti4 read1 read2 read3 read4 gen homecog subjid;
 time1=0; time2=1; time3=2; time4=3;
run;

data anti; set initial;
*must flip data for MIXED -- see Singer (1998); 
 array tvar[4] time1-time4; array antivar[4] anti1-anti4;
 do i=1 to 4; anti=antivar[i]; time=tvar[i]; output; end;
 drop i time1-time4 anti1-anti4;
run;

proc mixed data=anti noclprint covtest; class subjid;
*conditional linear anti;
 model anti = time gen homecog gen*time homecog*time/solution ddfm=bw notest;
 random intercept time / type=un sub=subjid gcorr;
run;