How Anxiety and Depression Overlap

There are a number of ways in which anxiety overlaps with depression. The particular ways in which anxiety manifests can be very similar to how depression manifests. For example, both difficulties can involve troubles with concentration, feelings of hopelessness, sleep disturbances, and similar difficulties (Barlow & Campbell, 2000: Zinbarg et al., 1994). Furthermore, both anxiety and depression can be treated with the same psychotropic medications; many of the SSRI medications, originally developed for treating depression, have been found as effective for reducing the symptoms of anxiety disorder (Meyer & Quenzer, 2004).

Differences between Anxiety and Depression

At the same time that there is a good deal of overlap between anxiety and depression, there are also important features that differentiate the two. Clark and Associates (1994) suggest that the central difference between anxiety and depression is a difference of positive and negative effect. The terms 'positive' and 'negative,' in this context, do not refer to good and bad, but rather to an increase or decrease of affect (here affect is another term for emotion).

Most of the symptoms associated with depression involve a decrease–such as a lowered mood, reduced energy, and a loss of interest in activities. Much of the symptoms associated with anxiety, involve an increase–such as heightened arousal, increased apprehension, and increased physical sensations of stress. Clark et al. (1994) state that there is pure depression, which only involves negative affect and pure anxiety, which involves both negative and positive affect.

Anxiety disorders and affective disorders in real-life are not likely to involve pure anxiety or pure depression, but instead are likely to be a combination of the two. Conditions that lean toward the negative-effect side are likely to be identified as depression whereas conditions that lean more toward positive-effect are likely to be identified as anxiety (Clark et al., 1994).