I know, this sounds like an oxymoron if there ever was one, but yes, there's romance in a psychological thriller and the emotions are as intense as the danger.  How can this be?  There is a deeper element to the emotional angst a hero and a heroine suffer when they are being hunted by a psychopath, as opposed to being a hostage or trying to solve a murder.

In both situations the hero and heroine are in danger and have to work together against a common enemy.  The saying that there is nothing like a common enemy to bring people together, is true for a reason.  Survival is a powerful instinct.   People will tend to put their own problems aside to survive.  The internal conflicts that cause sparks between the hero and heroine are put aside, even if they are lusting after one another while still wanting to push each other off a cliff, because they're so infuriating.

Because psychological thrillers fall into the romantic suspense genre they will follow many of the same paths that frustrate and endanger the hero and heroine.  In both, the hero and heroine will butt heads while they fight their foe and their internal conflicts will rise to the surface and become more evident as the danger increases.  Often times the danger will put the importance of the internal conflict into perspective.  Is it something that can be overcome?  Is it something worth even worrying about when looking at the big picture or will it be a deal breaker for the relationship?  This is only something the characters can answer.

The difference in the psychosocial thriller is an added element that ratchets up the emotions for the hero and heroine.  The villain is insane.  He not only puts them in danger over and over again, they often have no clue where or when it will happen.  The villain takes delight in playing with their minds.

This is where the thrill comes in for the reader.  In a mystery you, the reader, have to figure out who the murderer is, which is challenging.  In a thriller, you often know or at least meet the villain through their point of view and understand what they are going to do to the hero and heroine.  You want to warn them, but can't.  You can see the villain tearing down the hero and/or heroine's belief in themselves and each other.  This brings the emotional connection to another level, with you the reader. 

As the hero and heroine begin to look deeper inside and evaluate themselves the issues go deeper than the initial internal conflicts.  This process changes them as a person and makes them face their beliefs and values.  Will they hold strong or will the insanity they face cause them to lose themselves and possibly the one they love?  Once again, only the character can decide.

Some good examples of this would be: A villain that wants to push his victims to commit suicide, will the torture they endure be so great that they take the easy way out or will their belief that life is worth living regardless of the pain, win out?  Even though they don't believe in murder, will they be able to take a life and kill their tormentor?  Would they do it to protect someone they love, but not for themselves?  Or if their child's life were in jeopardy would they murder an innocent person as a form of ransom to free their child?

The hero and heroine also need to face each other after having committed something brutal.  Can either live with themselves or the other after?  The wrap-up after the black moment is vital to the story.  The reader needs to see how the hero and heroine are dealing with the fall out from the psychological and physical torture they have endured.  It should never be a quick and neat happily ever after.  It has to be believable yet emotionally satisfying to let us know that they have truly survived the ordeal with a chance at a happy ending.

The strength and depth of the emotions that are brought out in the psychological thriller allows for a strong romantic relationship, with or without steamy love scenes in the book.  It's all about the emotion and satisfying conclusion after a tension filled roller coaster ride.