“…Although relatively few studies have examined the psychological and psychosocial factors associated with TRD, treatment resistance in depression has been linked to an earlier age of onset (Dudek, et al, 2010;Souery, et al, 2007), more frequent (Dudek, et al, 2010;Sagud, et al, 2013) and recurrent (Souery, et al, 2007) episodes of depression, longer duration of illness (Sagud, et al, 2013), greater severity of depression (Souery, et al, 2007) and an older current age (Sagud, et al, 2013). Patients with TRD are also more likely to be hospitalised for treatment (Souery, et al, 2007) and to have a greater risk of suicide (Sagud, et al, 2013;Souery, et al, 2007;Pfeiffer, Kim, Ganoczy, Zivin & Valenstein, 2013).…”