What are the potential drawbacks of using regular expressions (regex) in PHP for input validation, and how can developers mitigate these risks?

One potential drawback of using regular expressions for input validation in PHP is the complexity and readability of the regex patterns, which can make it difficult to maintain and debug code. To mitigate this risk, developers can use built-in PHP functions like `filter_var()` or `preg_match()` with simpler regex patterns for common validation tasks.

// Example of using filter_var() for email validation
$email = "example@example.com";
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "Email is valid";
} else {
    echo "Email is invalid";
}