Major Depressive Disorder
Major depression accounts for one of the most common additional diagnosis of SAD (Szafranski, Talkovsky, Farris, & Norton, 2014). Individuals suffering from major depressive disorder are between three to six times more likely of meeting the criteria of social anxiety disorder than people without this diagnosis (Mineka, Watson, & Clark, 1998). Especially the generalized subtype tends to show more and stronger symptoms of depression (Szafranski, Talkovsky, Farris, & Norton, 2014). With the bigger number of feared and avoided situations, quality of life is affected in a more negative way. Therefore, depression is more likely to accompany this subtype of social anxiety disorder (Mineka et al., 1998).
As difficult as the co-occurrence of these two disorders may be, a positive note is that affected individuals are more likely to seek help than individuals who only suffer from SAD (Ohayon, & Schatzberg, 2010). It has been found that rates of social anxiety with additional major depression decrease as the age of patients increases. It is believed that due to the higher likelihood of seeking help in combination with the probable use of antidepressants at some point, odds of improvement throughout life are positive.
In most cases, social anxiety disorder develops first and major depressive disorder follows at a later point (Väänänen et al., 2011). Generally speaking, affected individuals start suffering earlier than those who only exhibit one of the two disorders alone (Erwin et al., 2002). The suffering provoked by the two disorders is also more intense for this subgroup.
Individuals with SAD and major depressive disorder who start a therapeutic process are as likely as other SAD sufferers to benefit from treatment (Erwin et al., 2002). Furthermore, it has been found that targeting social anxiety in treatment also significantly decreases depression (Moscovitch, Hofman, Suvak, & In-Albon, 2005). The effects of targeting only the symptoms of depression, on the contrary, has a way lower effect on social anxiety.
Persistent Depressive Disorder (PDD) / Dysthymic Disorder
Persistent Depressive Disorder (dysthymic disorder) describes pretty much the same symptoms as major depressive disorder. The difference lies in the chronic course of PDD and its lower symptom severity (Sansone, & Sansone, 2009). People diagnosed with SAD are about five times more likely to suffer from dysthymic disorder throughout their lifetime than people without diagnosed social anxiety (Wittchen & Fehm, 2004). Following this trend, people diagnosed with persistent depressive disorder often develop social anxiety disorder at some later point (Wells, Tien, Garrison, & Eaton, 1994). This especially refers to patients who experience PDD at an early age (before 21 years; Barzega, Maina, Venturello, & Bogetto, 2001). Just as for major depressive disorder, the generalized subtype of SAD is at a higher risk of suffering from PDD (Wittchen & Fehm, 2004).
Bipolar Disorder / Manic-Depressive Illness
People suffering from bipolar disorder experience unusual and significant mood swings and strong shifts in energy levels, as well as in physiological and cognitive arousal (The National Institute of Mental Health, 2015). It is also referred to as manic-depressive illness. Around 50% of people affected by bipolar disorder also receive a diagnosis of SAD at some point in their lives (Kessler, Stang, et al., 1999). It has been found that people suffering from manic-depressive illness display high levels of anxiety sensitivity (Simon et al., 2003). Being highly sensitive to experiencing anxiety is a risk factor for SAD and other anxiety disorders (Szafranski, Talkovsky, Farris, & Norton, 2014).
Treatment for people suffering from both bipolar disorder and SAD might need to be specialized (Dilsaver & Chen, 2003). Well planned, professionally guided pharmacotherapy and cognitive behavioral therapy are among the first recommendations (Szafranski, Talkovsky, Farris, & Norton, 2014; Freeman, Freeman, & McElroy, 2002).