The disorders are two sides of the same coin. Over the past couple of years, clinicians and researchers alike have been moving toward a new conclusion: Depression and anxiety are not two disorders that coexist. They are two faces of one disorder.

Are you anxious or are you depressed? In the world of mental health care, where exact diagnosis dictates treatment, anxiety and depression are regarded as two distinct disorders. But in the world of real people, many suffer from both conditions. In fact, most mood disorders present as a combination of anxiety and depression.

The coexistence of anxiety and depression-called comorbidity in the psych biz-carries some serious repercussions. It makes the course of disorder more chronic, it impairs functioning at work and in relationships more, and it substantially raises suicide risk."They're probably two sides of the same coin," says David Barlow, Ph.D., director of the Center for Anxiety and Related Disorders at Boston University. "The genetics seem to be the same. The neurobiology seems to overlap. The psychological and biological nature of the vulnerability is the same. It just seems that some people with the vulnerability react with anxiety to life stressors. And some people, in addition, go beyond that to become depressed.

Mental health professionals often have difficulty distinguishing anxiety from depression, and to some degree, they're off the hook. The treatments that work best for depression also combat anxiety. Cognitive-behavioural therapy (CBT) gets at response patterns central to both conditions. And the drugs most commonly used against depression, the SSRIs, or selective serotonin reuptake inhibitors, have also been proved effective against an array of anxiety disorders, from social phobia to panic and post-traumatic stress disorder (PTSD). Which drug a patient should get is based more on what he or she can tolerate rather than on symptoms.

Medication and CBT are equally effective in reducing anxiety/depression. But CBT is better at preventing relapse, and it creates greater patient satisfaction. It's more empowering. Patients like feeling responsible for their own success. Further, new data suggests that the active coping CBT encourages creates new brain circuits that circumvent the dysfunctional response pathways.