get_posts only retrieve post titles from one author

<?php
$myposts = get_posts('numberposts=10');
foreach($myposts as $post) :
?>
<li><a href="<?php the_permalink(); ?>"><?php the_title();
?></a></li>
<?php endforeach; ?>

i’m using the following code to retrieve 10 recent posts. my blog has 3 authors at the moment, but get_posts only list down posts made by one author (and it isn’t me). i’ve tried posting a new posts but it wasn’t shown in the list by get_posts. i even tried including a &orderby=post_date but the results still remains. help!