Psychiatric comorbidity in a population of Parkinson’s disease patients A. Nuti a , R. Ceravolo a , A. Piccinni b , G. Dell’Agnello a , G. Bellini a , G. Gambaccini a , C. Rossi a , C. Logi a , L. Dell’Osso b and U. Bonuccelli a a Department of Neuroscience, Neurology Section and b Department of Psychiatry, University of Pisa, Pisa, Italy Keywords: anxiety, depression, Parkinson’s disease, psychiatric comorbidity Received 30 June 2003 Accepted 28 August 2003 Behavioural disturbances are frequently observed in Parkinson’s disease (PD), inclu- ding mood and anxiety disorders. The existence of a comorbidity between such psy- chiatric disorders in PD patients has been suggested only in a few studies. To assess the prevalence of mood and anxiety disturbances, and the rate of comorbidity of such disorders in PD. Secondary aim was to correlate the prevalence of psychiatric disor- ders in PD with age, sex, laterality of motor symptomatology, clinical features, severity of disease, age of onset and PD duration, and anti-parkinsonian therapy. Ninety consecutive PD outpatients, and 90 age- and sex-matched controls were included. All PD patients enrolled were non-fluctuating (21 de novo, 69 treated with levodopa or dopamine agonists). PD patients and controls with Mini Mental State Examination score <23 were excluded. Psychiatric diagnosis was performed by semistructured interview according with DSM-IV criteria and the severity of depres- sive and anxious symptoms was rated with clinical rating scales. Major depression was found in 21.1% PD patients vs. 3.3% controls (P < 0.01, chi-square analysis), dys- timia in 18.8% PD patients vs. 4.4% controls (P < 0.05), panic disorders in 30% PD patients vs. 5.5% controls (P < 0.01). No difference in the prevalence of other anxiety disorders was observed between the two groups. The comorbidity of mood and anxiety disorders was found in 19.3% PD patients vs. 8.6% controls (P < 0.01). No correlation was reported between the prevalence of behavioural disturbances and any of the demographic, clinical or pharmacological data taken into account. Our findings might suggest the existence of a wide spectrum of psychiatric disorders in PD ranging from pure depressive disorders, comorbid depressive and anxiety disorders, and pure anxiety disorders, presumably linked to the same neurobiological substrate. Introduction Depression is the most common psychiatric disturbance reported in Parkinson’s disease (PD) and may cause significant functional impairment. Several clinical reports have documented a 30–40% risk for the occurrence of depression during the course of PD (Cummings, 1992; Slaughter et al., 2001); other studies, however, have reported a higher or lower prevalence (Mindham et al., 1970; Hantz et al., 1994; Tandberg et al., 1996). The descriptive and clinical characteristics of depression in PD have not been carefully investi- gated. In previous studies (Mayeux et al., 1986; Stark- stein et al., 1990) it has been reported that slightly more than half of the PD depressed patients met the criteria for major depression, whereas in the remaining pati- ents, dysthymia was diagnosed, in accordance with the Diagnostic and Statistical Manual of Mental Disorders. The aetiology of depressive disorder in PD is also not clear, some studies indicating a relationship between physical disability in PD and depression as a reactive state (Gotham et al., 1986), others suggesting that depression in PD is an intrinsic part of the disease and that it is related to the neuropathology of PD (Mayeux et al., 1986; Starkstein et al., 1990). Also anxiety disorders may be in association with PD, and both episodic and generalized anxiety syn- dromes have been reported to occur in PD populations at elevated rates compared with normal and disease controls (Richard et al., 1996; Walsh and Bennett, 2001). In some cases the onset of the anxiety sympto- matology may precede the motor symptoms of PD, suggesting some underlying shared neurobiological vulnerability to PD and anxiety (Lauterbach and Duvoisin, 1992). However, a wide spectrum of anxiety disorders varying from insomnia and jitteriness to panic disorders may be induced by dopaminergic therapy (Factor et al., 1995). Mood and anxiety disorders show an excess comor- bidity which is substantially more common than expected on the basis of their prevalence rates both in Correspondence: Roberto Ceravolo MD, Department of Neuro- science, Neurology Section, University of Pisa, Via Roma 67, 56126 Pisa, Italy (tel.: 0039-050-993145; fax: 0039-050-550563; e-mail: r.ceravolo@neuro.med.unipi.it). Ó 2004 EFNS 315 European Journal of Neurology 2004, 11: 315–320