Phoebe is terrified of driving. Even thinking about driving can make her heart race. Could she simply have driving phobia--a disorder the Diagnostic and Statistical Manual of Mental Disorders (DSM) would label as "specific phobia"? Perhaps, says Randi McCabe, PhD, a psychologist and chair of the clinical behavioral sciences program at McMaster University in Canada. However, Phoebe's reaction to cars might be better explained by panic disorder, or even social phobia, depending on what she fears might happen if she drove.

For example, if Phoebe fears she will crash the car, McCabe might diagnose her with having a specific phobia. However, if her fears are centered on the possibility of having a panic attack--perhaps because she had one before in a vehicle--she may better qualify for the diagnosis of panic disorder. And if Phoebe is terrified of how other drivers will appraise her driving, then she probably fits best under the definition of social phobia.

In each of these cases the client would probably experience the same symptoms--avoidance of driving and panic attacks in cars--which can make it difficult for clinicians to distinguish between different anxiety disorders, says McCabe. However, by looking closely at a client's fears, psychologists can chose the appropriate DSM category, target therapy and predict other situations that might provoke panic, says McCabe, who has written 11 articles and book chapters about anxiety disorders.

"With the specific phobias, the nature of the fear is very circumscribed to a single situation, stimulation or object," McCabe notes. In such a case, a therapist can confine treatment--usually exposure therapy--to the one target of the client's fear, she says.

However, if the client is afraid of the fear itself--what is known as panic disorder--that can translate into panic attacks almost anywhere. In such cases, a clinician might also expose the client to the racing heart and shallow breathing that accompany panic attacks, perhaps by asking the person to hyperventilate or jog, McCabe says.

Those who are afraid of being evaluated--for example, by other drivers--probably also fear social situations such as parties, and may need to practice controlling their fear in such settings, says McCabe.

But while the DSM categories can be useful, some clients defy classification, notes Martin Antony, PhD, director of the Anxiety Treatment and Research Centre at St. Joseph's Healthcare, Hamilton, in Canada. One such person might fear car accidents and the symptoms of panic, he says.

"The categorization gets you some gross idea of how you might go about handling the problem...but it also misses out on important information," Antony says. "We may know driving triggers the panic, but we want to know if it matters what lane they are in...Do they avoid the situation or try to escape it?"

By thoroughly assessing all of the parameters of a client's fear, clinicians can be better prepared to attack the problem, he notes.