Capture reaction time - code not working

Hi,

I'm trying to capture simple reaction time, but the code I have isn't working (i.e., gives me RT of 0.00000008, etc.).

Here is what I have...

    secs0=GetSecs; % Wait for a keyboard response
    respToBeMade = true;
    while respToBeMade 
        [keyIsDown,secs, pressedKeys] = KbCheck;
        if pressedKeys(escapeKey);
            ShowCursor;
            sca;
            return;
        elseif pressedKeys(upKey);
            keyResp = 's';
            respToBeMade = false;
        elseif pressedKeys(downKey);
            keyResp = 'l';
            respToBeMade = false;
        end
    end

    RT=secs-secs0; % Get reaction time

Is there something that is clearly wrong here? I can't seem to figure it out, it looks right to me. I'm also using Psychtoolbox if that makes a difference.

Thank you!