Of course! I believe almost all PHP devs noticed, they have terrible slowdown by Doctrine and used XDebug to check where is the problem. I am not PHP dev anymore and I hope it has improved a lot since my last adventure with this ORM but I'd still advocate to not use it on client-facing interface - you can use Doctrine only for database management (CLI), while for web interface use raw PDO or equivalent (Eloquent). You can also use cache or transform page into static-site. Sky is the limit.