A prospective study conducted in Sweden showed that both anxiety and depression were associated with future insomnia and insomnia was associated with future anxiety and depression. 17 A baseline diagnosis of anxiety significantly predicted future insomnia, while an insomnia diagnosis at baseline significantly predicted future depression. A communitybased retrospective study identified that chronic insomnia sufferers were about 10 times more likely to have clinically significant depression and

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... out 17 times more likely to have clinically significant anxiety. 20 Chronic insomnia has been found to increase the risk of developing depression anywhere from 2 to 40 fold and those being treated for depression and have concomitant chronic insomnia are 2 to 4 times more likely to remain depressed if the insomnia remains untreated. [21] [22] [23] www.intechopen.com Treatment of Insomnia with Comorbid Mental Illness 85 7. Comorbidity treatment stategies N e a r l y 8 0 % o f p a t i e n t s d i a g n o s e d w i t h m a j o r d e p r e s s i v e d i s o r d e r ( M D D ) h a v e s l e e p disturbances with disturbed sleep and fatigue remaining after successful treatment of the mood disorder. 21, 23, 24, 28, 30 Lingering insomnia following treatment of depression is associated with increased risk of relapse (more than 50% of cases). 21,24,30 Therefore, insomnia is a significant independent predictor of future depression. 14, [22] [23] [24] 29 Clinical sequelae of insomnia such as negative affect, fatigue, anhedonia, poor concentration, and irritability are also symptoms found in depression. As mentioned earlier, a bidirectional relationship between depression and insomnia exists thereby emphasizing the importance of treating the insomnia independent of the comorbid condition. 24,28,31 Treatment strategies Several treatment strategies are utilized, often in various combinations, for the treatment of insomnia. These include psychological and behavioral therapy (PBT), pharmacotherapy, over-the-counter (OTC) medications, herbal and dietary supplements, complementary and alternative medicine (CAM), mind-body and lifestyle interventions (Table 1) . Lifestyle: sleep hygiene, weight control, low impact exercise, dietary (e.g. elimination of caffeine, nicotine, alcohol) OTC medications: Not recommended by AASM and NIH Herbal / Dietary supplements: melatonin (for changes in circadian rhythm, jet lag, shift work, or documented deficiency only); valerian (for acute treatment only) PBT: stimulus control, coping skills, relaxation training (e.g. progressive muscle relaxation, guided imagery, abdominal breathing), CBT-I, multi-component therapy, sleep restriction, paradoxical intension, biofeedback, grief management Mind and Body: yoga, meditation, mindfulness-based programs (MBSR, MBCT, MBT-I, MBRP), tai chi, acupuncture, acupressure Pharmacological: SSRI or SNRI, augmentation with sedating antidepressant (low dose), BzRA (for acute treatment only), or benzodiazepine (minimal use: for acute or "as needed" treatment of anxiety symptoms only), prazosin KEY: AASM = American Academy of Sleep Medicine; BzRA = benzodiazepine receptor agonist; CBT-I = cognitive behavioral therapy for insomnia; MBSR = mindfulness-based stress reduction; MBCT = mindfulness-based cognitive therapy; MBT-I = mindfulness based therapy for insomnia; MBRP = mindfulness-based relapse prevention; NIH = National Institutes of Health; OTC = over-the-counter; PBT Psychological and Behavioral Therapy; SNRI -serotonin norepinephrine receptor inhibitor; SSRI = selective serotonin reuptake inhibitor, TCA = tricyclic antidepressant