A couple of recent research studies have underlined the value of specific forms of psychotherapy for complicated grief reactions: 

Shear, M. K., et al. (2014). "Treatment of complicated grief in elderly persons: a randomized clinical trial." JAMA Psychiatry 71(11): 1287-1295.  IMPORTANCE: Complicated grief (CG) is a debilitating condition, most prevalent in elderly persons. However, to our knowledge, no full-scale randomized clinical trial has studied CG in this population. OBJECTIVE: To determine whether complicated grief treatment (CGT) produces greater improvement in CG and depressive symptoms than grief-focused interpersonal psychotherapy (IPT). DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial enrolling 151 individuals 50 years or older (mean [SD] age, 66.1 [8.9] years) scoring at least 30 on the Inventory of Complicated Grief (ICG). Participants were recruited from the New York metropolitan area from August 20, 2008, through January 7, 2013, and randomized to receive CGT or IPT. The main outcome was assessed at 20 weeks after baseline, with interim measures collected at 8, 12, and 16 weeks after baseline. INTERVENTIONS: Sixteen sessions of CGT (n = 74) or IPT (n = 77) delivered approximately weekly. MAIN OUTCOMES AND MEASURES: Rate of treatment response, defined as a rating from an independent evaluator of much or very much improved on the Improvement subscale of the Clinical Global Impression Scale. RESULTS: Both treatments produced improvement in CG symptoms. Response rate for CGT (52 individuals [70.5%]) was more than twice that for IPT (24 [32.0%]) (relative risk, 2.20 [95% CI, 1.51-3.22]; P < .001), with the number needed to treat at 2.56. Secondary analyses of CG severity and CG symptom and impairment questionnaire measures confirmed that CGT conferred a significantly greater change in illness severity (22 individuals [35.2%] in the CGT group vs 41 [64.1%] in the IPT group were still at least moderately ill [P = .001]), rate of CG symptom reduction (1.05 ICG points per week for CGT vs 0.75 points per week for IPT [t633 = 3.85; P < .001]), and the rate of improvement in CG impairment (0.63 work and Social Adjustment Scale points per week with CGT and 0.39 points per week with IPT [t503 = 2.87; P = .004]). Results were not moderated by participant age. CONCLUSIONS AND RELEVANCE: Complicated grief treatment produced clinically and statistically significantly greater response rates for CG symptoms than a proven efficacious treatment for depression (IPT). Results strongly support the need for physicians and other health care providers to distinguish CG from depression. Given the growing elderly population, the high prevalence of bereavement in aging individuals, and the marked physical and psychological impact of CG, clinicians need to know how to treat CG in older adults. 

Bryant, R. A., et al. (2014). "Treating prolonged grief disorder: a randomized clinical trial." JAMA Psychiatry 71(12): 1332-1339.  IMPORTANCE: Prolonged grief disorder (PGD) is a potentially disabling condition that affects approximately 10% of bereaved people. Grief-focused cognitive behavior therapy (CBT) has been shown to be effective in treating PGD. Although treatments for PGD have focused on exposure therapy, much debate remains about whether exposure therapy is optimal for PGD. OBJECTIVE: To determine the relative efficacies of CBT with exposure therapy (CBT/exposure) or CBT alone for PGD. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial of 80 patients with PGD attending the outpatient University of New South Wales Traumatic Stress Clinic from September 17, 2007, through June 7, 2010. INTERVENTIONS: All patients received 10 weekly 2-hour group therapy sessions that consisted of CBT techniques. Patients also received 4 individual sessions, in which they were randomized to receive exposure therapy for memories of the death or supportive counseling. MAIN OUTCOMES AND MEASURES: Measures of PGD by clinical interview and self-reported measures of depression, cognitive appraisals, and functioning at the 6-month follow-up. RESULTS: Intention-to-treat analyses at follow-up indicated a significant quadratic time x treatment condition interaction effect (B [SE], 0.49 [0.16]; t120.16 = 3.08 [95% CI, 0.18-0.81]; P = .003), indicating that CBT/exposure led to greater PGD reductions than CBT alone. At follow-up, CBT/exposure led to greater reductions in depression (B [SE], 0.35 [0.12]; t112.65 = 2.83 [95% CI, 0.11-0.60]; P = .005), negative appraisals (B [SE], 0.68 [0.25]; t109.98 = 2.66 [95% CI, 0.17-1.18]; P = .009), and functional impairment (B [SE], 0.24 [0.08]; t111.40 = 3.01 [95% CI, 0.08-0.40]; P = .003) than CBT alone. In terms of treatment completers, fewer patients in the CBT/exposure condition at follow-up (14.8%) met criteria for PGD than those in the CBT condition (37.9%) (odds ratio, 3.51; 95% CI, 0.96-12.89; chi2 = 3.81; P = .04). CONCLUSIONS AND RELEVANCE: Including exposure therapy that promotes emotional processing of memories of the death is an important component to achieve optimal reductions in PGD severity. Facilitating emotional responses to the death may promote greater changes in appraisals about the loss, which are associated with symptom reduction. Promotion of emotional processing techniques in therapies to treat patients with PGD is needed. 

As the useful JAMA general information leaflet on grief points out "Sometimes grief progresses from an emotionally painful but normal experience to a disorder requiring additional evaluation and treatment."  Many normal grief responses will start to diminish after six months or so - see Maciejewski et al's 2007 paper "An empirical examination of the stage theory of grief" - but for some people this doesn't happen and normal grief is coloured by other factors.  The JAMA page specificially highlights "• Complicated grief may be present when the emotions are particularly long-lasting or severe and include inability to accept the loved one’s death, persistent thoughts regarding the death, and preoccupation with thoughts about the loved one.  • Major depressive disorder should be considered when the duration of grief lasts more than 2 months and is associated with persistent feelings of guilt (other than those associated with the loved one’s death), preoccupation with thoughts about death (other than the loved one’s), feelings of worthlessness, psychomotor retardation (the slowing down ofnormal movements), and the inability to perform daily activities. • Posttraumatic stress disorder may be present if the death occurred in a violent or traumatic manner, particularly if the patient also witnessed it. In these cases, the person has recurrent disturbing recollections of the death, avoidance of situations associated with the death, and increased arousal (activation), such as difficulty sleeping, difficulty concentrating, and anger outbursts."  Prigerson et al's excellent (free full text) 2009 paper "Prolonged grief disorder: Psychometric validation of criteria proposed for DSM-V and ICD-11" gives diagnostic criteria for complicated/prolonged grief disorder.

More to follow ...