Introduction 1 3 4 5 6 ICDs’ phenomenology, epidemiology and relationship with OCD The failure to resist an impulse to perform some act that is harmful to the individual or others; An increasing sense of arousal or tension prior to committing or engaging in the act; An experience of either pleasure, gratification, or release of tension at the time of committing the act. In addition, there is usually a pattern of engaging in the abnormal behavior in spite of adverse consequences (e.g., criminal changes, impairment of normal functioning, etc.). To demonstrate that a relationship exists between ICDs and OCD, there should be evidence that OCD is overrepresented in patients with ICDs and/or that ICDs are overrepresented in patients with OCD. Studies examining rates of OCD in patients with ICDs have reported inconsistent results, with some ICDs showing relatively high rates of comorbidity with OCD (trichotillomania, CI-shopping), and others demonstrating low rates (intermittent explosive disorder, pathological gambling, and C–I sexual behaviors). 4 7 8 9 1 10 12 13 14 15 16 17 Table 1 Prevalence estimates of impulse control disorders Impulse control disorder Reference Type of community Prevalence reported Pathological Gambling Gerstein et al. (1999) Adult population 1–3%  Welte et al. (2001) Adult population  Trichotillomania Christenson et al. (1991) College students 1.5% males; 3.4 females Pyromania Kosky and Silburn (1984) Children and adolescents 2.4–3.5%  Kolko et al. (1988) Children and adolescents   Jacobson (1995) Children and adolescents  Intermittent Explosive Disorder Monopolis and Lion (1983) Psychiatric surveys 1–2% Coccaro et al. (2004) Adult population Lifetime 11.1%; 1 month 3.2% Kleptomania Goldman (1991) Adult population 0.6% C–I Internet Usage Disorder – – – C–I Shopping Black et al. (2001) Adult population  2–8% C–I Skin Picking Doran et al. (1985) Dermatologic patients 2% Gupta et al. (1986) Dermatologic patients C–I Sexual Behaviors Shaffer and Zimmerman (1990) Adult population 5–6% Coleman, 1991 Adult population 18 19 1 20 21 22 23 1 24 25 26 24 27 28 29 30 2 Table 2 OCD rates in impulse control disorders Impulse control disorder Reference Rates of OCD Pathological Gambling Argo and Black (2004) 1–20% Trichotillomania Christenson and Mansueto (1999) 3–27% Pyromania – – Intermittent Explosive Disorder McElroy et al. (1998) 22% Kleptomania Presta et al. (2002) 6.5–60% C–I Internet Usage Disorder Black et al. (1999) 0% current; 10% lifetime Shapira et al. (2000) 15% current; 20% lifetime C–I Shopping Christenson et al. (1994) 12.5–30% McElroy et al. (1998) C–I Skin Picking Simeon et al. (1997) 6–52% Arnold et al. (1998) Wilhelm et al. (1999) C–I Sexual Behaviors Kafka and Prentky (1994) 12–14% Black et al. (1997) 31 32 1 33 1 34 35 36 37 2 38 39 39 40 41 42 1 43 44 45 46 47 48 49 50 51 4 52 53 54 1 55 4 56 57 58 2 59 61 62 63 1 62 64 65 66 67 68 2 69 70 72 73 74 75 76 74 71 71 77 78 2 79 80 80 80 81 1 82 83 79 84 2 85 86 87 1 86 88 2 59 61 89 90 91 1 38 92 93 92 93 94 2 38 Treatment options for ICDs 3 Table 3 Treatment options for impulse control disorders as reported in blinded and unblinded studies Impulse Control Disorder Double-blind studies (references) Outcomes Other treatment options as reported in open-label trials Pathological Gambling Fluvoxamine vs. PC (Hollander et al. 2000;  Blanco et al. 2002) SSD for Fluvoxamine; No SSD  between Fluvoxamine and PC.  Nefazodone, Bupropion, Citalopram,  Divalproex, Topiramate Paroxetine vs. PC (Kim et al. 2002;  Potenza et al. 2003) SSD for Paroxetine; No SSD between  Paroxetine and PC.  Lithium vs. PC (Hollander et al. 2005) SSD for Lithium; Naltrexone vs. PC (Kim et al. 2001) SSD for Naltrexone Trichotillomania Clomipramine vs. Desipramine  (Swedo et al. 1989) SSD for Clomipramine; Fluvoxamine, Citalopram, Venlafaxine,  Naltrexone, Lithium, CBT Fluoxetine vs. PC (Christenson et al. 1991;  Streichenvein and Thornby 1995) No SSD between Fluoxetine and PC Pyromania – – CBT and other psychotherapies Intermittent  Explosive Disorder *Lithium vs. PC (Campbell et al. 1984 and  1995; Malone et al. 1998 and 2000)  SSD for Lithium (in the Campbell’  study of 1984, Lithium was  associated to Haloperidol) Clonidine *Divalproex vs. PC  (Hollander et al. 2003 and 2005)  SSD for Divalproex *Fluoxetine vs. PC (Coccaro et al. 1997)  SSD for Fluoxetine *Carbamazepine vs. PC (Foster et al. 1989)  SSD for Carbamazepine *Phenytoin vs. PC (Barratt et al. 1997;  Stanford et al. 2001)  SSD for Phenytoin *BBlockers vs. PC  (Greendyke et al. 1986a and 1986b)  SSD for BBlockers *Risperidone vs. PC (Buitelaar et al. 2001;  Findling et al. 2001)  SS for Risperidone *CBT vs. PC (Alpert et al. 1997) SSD for CBT Kleptomania – – Fluoxetine, Paroxetine, Fluvoxamine,  Divalproex, Lithium, Benzodiazepines C–I Internet Usage  Disorder Escitalopram vs. PC  (Dell’Osso et al. 2006**) SSD for Escitalopram Psychotherapy C–I Shopping Fluvoxamine vs. PC (Black et al. 2000;  Ninan et al. 2000) No SSD between Fluvoxamine  and PC; Fluvoxamine, Naltrexone Citalopram vs. PC (Koran et al. 2003) SSD for Citalopram C–I Skin Picking Fluoxetine vs. PC (Simeon et al. 1997;  Block et al. 2000) SSD for Fluoxetine Clomipramine, Sertraline C–I Sexual Behaviors – – Lithium, Tricyclics, Buspirone,  Fluoxetine, Nefazodone,  Sertraline, Naltrexone SSD = statistically significant differences; CBT = cognitive behavioral therapy; PC = placebo * Studies on patients with impulsive aggression features, rather than with a proper DSM diagnosis of IED ** Open-label study followed by double-blind discontinuation phase (Abstract) 22 95 99 3 100 97 98 101 102 103 104 3 105 106 110 111 112 113 116 117 118 117 119 120 121 2 3 122 123 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 3 64 143 144 145 148 64 144 145 64 149 64 148 150 64 147 151 152 153 154 155 3 156 158 159 162 163 164 165 166 167 3 86 168 169 170 171 172 173 97 3 174 175 176 177 Conclusions Current knowledge on ICDs in terms of epidemiology and pharmacological treatment varies notably across these disorders, with recent and continuing advances for some (i.e. pathological gambling and C–I shopping), and anecdotal and obsolete data for others. Undoubtedly, given the high prevalence estimates of some ICDs (i.e. pathological gambling and C–I sexual behaviors) as well as their comorbidity with other major psychiatric disorders, this group of disorders represents a global problem. Nevertheless, certain ICDs (i.e, pyromania, C–I Internet usage disorder) still need systematic epidemiological and pharmacological research. Studying the relationships between specific ICDs and other major psychiatric conditions (i.e. OCD, bipolar disorders, addictive disorders) in terms of phenomenological issues and comorbidity patterns is not only of theoretical interest; indeed, it provides the rationale for the use of specific pharmacological treatments and behavioral interventions. From this perspective, more than one decade after its introduction, the conceptualization of ICDs as obsessive–compulsive related disorders is still valid and has been confirmed by numerous studies; however, there is also evidence supporting the relationship between ICDs and addictive and affective disorders. Not only are the different models of conceptualizing the ICDs not mutually exclusive, but they can contribute to recognize specific subtypes within the disorders. As a result, different models of conceptualization of ICDs have led new developments in pharmacologic treatment of these disorders, with positive results obtained with mood stabilizers and opioid antagonists in addition to the SSRIs.