Schizophrenia Research

Schizophrenia Research 139 (2012) 40 45 Contents lists available at SciVerse ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres [ 123 I]FP-CIT single photon emission computed tomography findings in drug-induced Parkinsonism Michele Tinazzi a, Andrea Cipriani b, Angela Matinella a,, Antonino Cannas c, Paolo Solla c, Alessandra Nicoletti d, Mario Zappia d, Letterio Morgante e, Francesca Morgante e, Claudio Pacchetti f, Massimo Sciarretta f, Carlo Dallocchio g, Simone Rossi h, Maria Malentacchi h, Roberto Ceravolo i, Daniela Frosini i, Stelvio Sestini j, Tommaso Bovi a, Corrado Barbui b a Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Italy b Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, University of Verona, Italy c Department of Cardiovascular and Neurological Sciences, Section of Neurology, University of Cagliari, Italy d Department GF Ingrassia, Section of Neurosciences, University of Catania, Italy e Department of Neurosciences, Psychiatric and Anaesthesiological Sciences, University of Messina, Italy f Department of Applied Health and Psycho-behavioural Sciences, Section of Psychiatry, University of Pavia, Italy g City Hospital of Voghera, Unit of Neurology, Italy h Department of Neurosciences, Section of Neurology, University of Siena, Italy i Department of Neurosciences, University of Pisa, Italy j Unit of Nuclear Medicine, Hospital of Prato, Italy article info abstract Article history: Received 28 December 2011 Received in revised form 8 May 2012 Accepted 2 June 2012 Available online 20 June 2012 Keywords: Schizophrenia Parkinsonism [ 123 I]FP-CIT SPECT Antipsychotics Dopamine receptors Drug-induced parkinsonism (DIP) in patients treated with antipsychotic drugs is considered a form of postsynaptic parkinsonism, caused by D2-receptor blockade. Recent studies, however, carried out on small and heterogeneous patient samples, have shown that DIP may be associated with [ 123 I]FP-CIT single photon emission computed tomography (SPECT) abnormalities, which are markers of dopamine nigrostriatal terminal defect. In the present study, outpatients fulfilling the DSM-IV criteria for schizophrenia and treated with antipsychotics for at least 6 months, were enrolled in order to estimate the prevalence of DIP and, among patients with DIP, the prevalence of [ 123 I]FP-CIT SPECT abnormalities. Socio-demographic and clinical variables associated with the presence of DIP and SPECT abnormalities were also assessed. DIP was diagnosed in 149 out of 448 patients with schizophrenia (33%). Age, use of long-acting antipsychotics and a positive family history of parkinsonism were the only demographic variables significantly associated with the development of DIP. Neuroimaging abnormalities were found in 41 of 97 patients who agreed to undergo [ 123 I]FP-CIT SPECT (42%). Only age differentiated this group of patients from those with normal imaging. These preliminary findings suggest that D2-receptor blockade may coexist with a dopamine nigrostriatal terminal defect, as assessed by [ 123 I]FP-CIT SPECT abnormalities, in a relevant proportion of DIP patients. Longitudinal studies should be designed with the aim of improving our understanding of the mechanisms of presynaptic abnormalities in DIP patients and identifying specific treatment strategies. 2012 Elsevier B.V. All rights reserved. 1. Introduction Drug-induced parkinsonism (DIP), the most frequent form of secondary parkinsonism, usually develops in patients treated with antipsychotic drugs (APs) within 3 months of medication exposure (Susatia and Fernandez, 2009). The prevalence of DIP in patients treated with Corresponding author at: Dipartimento di Scienze Neurologiche, Neuropsicologiche, Morfologiche e Motorie, Università degli Studi di Verona, Piazzale L.A. Scuro, 1, Verona, Italy. E-mail address: angimatinella@libero.it (A. Matinella). APs has been estimated at around 20 30% (Muscettola et al., 1999; Modestin et al., 2000, 2008; Janno et al., 2004). Clinically, the symptoms are typically indistinguishable from those of Parkinson's disease (PD) (Susatia and Fernandez, 2009). Symmetry of symptoms and signs, together with the absence of tremor, has been considered typical of DIP (Hausner, 1983). Asymmetry may occur, however, in about 30 40% of patients (Hassin-Baer et al., 2001) or even more (54% in the study conducted by Hardie and Lees, 1988), and the presence of tremor has been reported in 44 50% of patients with DIP (Hardie and Lees, 1988; Hassin- Baer et al., 2001). Probably, the most common distinctive feature of DIP is its association with other drug-induced complications such as tardive 0920-9964/$ see front matter 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.schres.2012.06.003

M. Tinazzi et al. / Schizophrenia Research 139 (2012) 40 45 41 dyskinesias, which occur in 25 40% of patients (Richardson and Craig, 1982; Jankovic and Casabona, 1987). After drug withdrawal, most patients recover within a few months but, in a minority of cases, DIP persists or even worsens (Miller and Jankovic, 1989; Burn and Brooks, 1993), suggesting the possibility of a concomitant nigrostriatal defect. The functional integrity of dopaminergic nigrostriatal pathway can be studied with single photon emission computed tomography (SPECT) imaging by using ligands (i.e. [ 123 I]FP-CIT) of pre-synaptic dopamine transporter (DAT). While several [ 123 I]FP-CIT SPECT studies have reported a significant loss of striatal DAT binding in patients with pre-synaptic parkinsonism (Kägi et al., 2010), SPECT is expected to be normal in DIP patients (Tolosa et al., 2003), according to the view that DIP is a form of post-synaptic parkinsonism caused by D2- receptor blockade. Recent studies, however, have reported reduced nigrostriatal DAT binding in a relatively high percentage of DIP patients, ranging from 43% to 55% (Lorberboym et al., 2006; Tinazzi et al., 2008), thus suggesting a possible concomitant dopamine nigrostriatal terminal defect in a subgroup of DIP patients. These studies present several limitations, however, including small sample sizes and a high degree of heterogeneity in terms of psychiatric diagnoses, limiting the interpretation of the results. The aim of the present study was to assess in a large sample of schizophrenia patients (a) the prevalence of DIP; (b) the prevalence of SPECT abnormalities in patients with a diagnosis of DIP; (c) the socio-demographic and clinical variables associated with the presence of DIP and SPECT abnormalities. 2. Methods 2.1. Patients Outpatients fulfilling the DSM-IV criteria for schizophrenia were consecutively enrolled by an expert psychiatrist in each of 8 psychiatric centers participating in the study. As parkinsonian syndromes are rarely seen before the age of 40, only patients aged 40 years or above, receiving pharmacological treatment with one or more APs for at least 6 months, were selected. Socio-demographic and clinical information including age, sex, onset of schizophrenic symptoms, medical and family history of psychiatric or neurological disease and a detailed history of pharmacological treatment including type, dosage and duration of current AP treatment and other psychotropic drugs (benzodiazepines, antiepileptic drugs, tricyclic antidepressants) were obtained from patients and/or their relatives and/or clinical records. Associated medical conditions such as diabetes, hypertension and other neurological diseases and their treatment were also recorded. Patients with a prior history of PD and patients treated with drugs (other than APs) that may be associated with DIP (flunarizine, cinnarizine, fluoxetine and other selective serotonin reuptake inhibitors, reserpine and tetrabenazine, metoclopramide, prochlorperazine), as well as patients using illicit drugs (such as cannabis and hard drugs), were excluded from the study. 2.2. Assessments Patients were only included in the study after giving written, informed consent. All study centers obtained full approval for the study from the appropriate local ethics committee (institutional review board). Patients were informed by the treating psychiatrist as to the nature of the study and underwent clinical neurological assessment performed by a neurologist with training in movement disorders. The diagnosis of DIP was considered when at least two of the three basic parkinsonian signs (rest tremor, rigidity, bradykinesia) were present (Lorberboym et al., 2006; Tinazzi et al., 2008). Patients treated with anticholinergic drugs (orphenadrine, biperiden) were examined by the neurologist after a wash-out period lasting at least 3 days, after which the treatment could be resumed. The patients recruited underwent a quantitative assessment of parkinsonian motor symptoms using the Unified Parkinson Disease Rating Scale (UPDRS) motor score (part III). Items 20 26 of the UPDRS part III were used to assess the degree of clinical asymmetry in the upper and lower limbs. A difference 4 points in items 20 26 of the UPDRS III between the more and less affected sides was considered indicative of clinical asymmetry (Tinazzi et al., 2008). Any other antipsychotic-related movement disorders were also recorded by the neurologist. 2.3. SPECT methods All eligible patients underwent a bio-molecular imaging SPECT scan with [ 123 I]-Iofluopane (DaTSCAN, GE Healthcare Limited Little Chalfont, Bucks UK). The SPECT data were acquired in five of eight participating centers (Verona, Siena Pisa, Catania Messina, Pavia Voghera, Cagliari), as exactly the same gamma-camera system was available in these five centers only. For comparative purposes, all SPECT procedures were standardized between centers and performed according to EANM guidelines (Darcourt et al., 2010). The SPECT study was performed within 3 weeks of the neurological clinical assessment. Intravenous administration of 185 MBq [ 123 I]- Iofluopane was carried out after thyroid blockade with an adequate regimen (400 mg of sodium perchlorate per os given at least 5 min prior to injection) in all patients to prevent free radioactive iodine from accumulating in the thyroid. Acquisition of SPECT data was started 3 h and 30 min after the radioligand administration. The rationale for the delay between radioligand injection and image acquisition is that striatal DaTSCAN binding has been shown to reach a peak within 3 h of injection of the tracer and to remain stable between 3 and 6 h, thus allowing the condition of transient equilibrium which is mandatory for visual and semi-quantitative analysis of DaT images (Booij et al., 1999). For this reason, obtaining images within the time period of 3 6 h is recommended in the clinical routine (Darcourt et al., 2010). In addition, we established a standardized fixed time delay between injection and the start of data acquisition to minimize possible differences in quality images due to differences in counts related to radioactive decay over time. All SPECT data were acquired using a triple head rotating gamma camera (IRIX, Philips Netherlands) equipped with ultra-high resolution parallel-hole collimators. A polycarbonate head holder was used to reduce head movement during scanning. All patients were closely observed during scanning to detect head movement or dyskinesias. A standardized acquisition protocol was adopted in the different centers. Acquisition consisted of 120 projections recorded in a step-andshoot mode over a 360 rotation arc (each head acquired 40 projections). The angular step was 3, and the time frame was 40 s per step. Each acquisition was completed in 26 min. The acquisition matrix was 128 128, with 3.5 mm sampling. Projection data were reconstructed using a standardized iterative algorithm compensating for the spatial response of the collimator and filtered with a low-pass filter (order 4.00, cut-off frequency 0.30 pixel 1 ). Attenuation correction using Chang's method was performed for each slice, with a uniform attenuation coefficient of 0.11 (Chang, 1978). Transverse, coronal and sagittal canthomeatal-oriented slices (4.7 mm thick) were created for the purposes of visual analysis. 2.4. SPECT imaging All image data were sent to, and analyzed in, one center where they were visually rated as normal or abnormal by a nuclear medicine reader, expert and trained in neuroimaging. The reader was blinded to clinical data. According to Benamer et al. (2000), the scan was rated as normal in the presence of a homogeneous, symmetric uptake

42 M. Tinazzi et al. / Schizophrenia Research 139 (2012) 40 45 in the striatum, the most anterior part being the caudate nucleus, and the most posterior the putamen. Abnormal patterns were categorized as Grade I (asymmetric uptake with normal or almost normal putamen activity in one hemisphere and with a more marked reduction in the contralateral putamen), Grade II (significant bilateral reduction in putamen uptake with activity confined to the caudate nuclei) and Grade III (virtually no uptake bilaterally, affecting both the putamen and caudate nuclei). The choice of using visual assessment was supported by the fact that this approach had shown high accuracy and reliability in multicentre studies aimed at determining normal or reduced nigrostriatal DAT binding (Benamer et al., 2000; Scherfler and Nocker, 2009; Kägi et al., 2010). 2.5. Statistical analysis Categorical data were analyzed by chi-square statistics, and Mann Whitney two-sample statistics were used to analyze continuous data which were not normally distributed. AP doses prescribed at discharge were converted into multiples of the defined daily dose (DDD) for each drug by dividing the prescribed daily dose (PDD) by the DDD [PDD/DDD]. The DDD is the international unit of drug usage approved by the World Health Organisation for drug use studies. It is a theoretical unit of measurement defined as the assumed average daily maintenance dose for a drug, used for its main indication in adults. Expression of drug use in terms of multiples of DDDs makes it possible to calculate a cumulative measure of drug consumption for each patient, taking into account the concurrent use of more than one agent. A PDD/ DDD ratio of one indicates that the dose prescribed is equal to the DDD of that drug; a ratio greater than one indicates a dosage higher than the DDD of that drug, while a ratio lower than one means a dose lower than the DDD of that drug. For the purposes of this analysis, in order to maintain a conservative approach, a ratio greater than two was defined as a high AP dose. To examine factors associated with a diagnosis of DIP, we adopted a backward stepwise logistic regression analysis model, using diagnosis of DIP as the dependent variable. The following independent variables were inserted into the model: sex (female = 0, male = 1), age (years, continuous variable), family history of parkinsonism (no = 0, yes = 1), physical illness (no = 0, yes = 1), second generation APs (no = 0, yes = 1), long-acting AP drugs (no = 0, yes = 1), AP drugs (number, continuous variable), AP dose (DDDs, continuous variable), anticholinergic drugs (no = 0, yes = 1), other psychotropic drugs (no = 0, yes = 1). A p value of 0.05 specified the significance level for removal from the model. A second backward stepwise logistic regression analysis model using the same independent variables was adopted in the subsample of patients with DIP in order to examine factors associated with abnormal SPECT. A p value of 0.05 specified the significance level for removal from the model. 3. Results A total of 448 patients (F:M=222:226) with schizophrenia met the eligibility criteria and were entered into the study. Mean age and mean duration of psychosis were 55.3 (SD 10.7) and 23 (SD 12.9) years, respectively. Two hundred and twelve of 448 patients had a concomitant medical illness (mostly diabetes and/or hypertension). At study entry, 338 patients were taking only one AP, and the majority were treated with second-generation APs (N=336; 75%). Most patients were treated with APs at a standard dose (N=397; 88.6%) with an oral formulation (N=384; 85.7%). Eight of the 64 patients who received longacting antipsychotics were treated with a new-generation long-acting agent (risperidone). Two hundred and fifty-four patients (56.6%) were also treated with other psychotropic drugs, including benzodiazepine, antiepileptic drugs, and tricyclic antidepressants. Family history of parkinsonism was recorded in 17 patients (3.7%). 3.1. Prevalence and socio-demographic and clinical features of DIP patients A diagnosis of DIP was made in 149 patients, amounting to a prevalence of 33% (95% confidence interval (CI) 28 to 37%). Patients with DIP did not differ substantially from patients without DIP with respect to most of the socio-demographic variables, although DIP patients were significantly older (pb0.001), more often had a positive family history of parkinsonism (when at least one first degree relative was reported to be affected by parkinsonism) (p=0.005) and more often were receiving long-acting AP drugs (p=0.027) (Table 1). The multiple logistic regression model that included all these variables yielded a significant association of DIP with age, family history of parkinsonism and long-acting formulation (not shown). In terms of specific neurological symptoms (Table 2), as expected, patients with DIP were substantially different from patients without DIP. It should be pointed out, however, that specific neurological symptoms were also present in patients without a diagnosis of DIP. Additionally, tardive dyskinesia was significantly more frequent in DIP patients. The UPDRS III total score was significantly higher in DIP patients. 3.2. Prevalence and socio-demographic and clinical features of DIP patients with abnormal SPECT Among the 149 patients with DIP, 97 (65%) underwent [ 123 I]FP- CIT SPECT, while the remaining 52 denied. Patients who refused to participate did not differ significantly in terms of demographic and clinical features from those who agreed to participate (data not shown, but available on request from the authors). Abnormal SPECT findings were found in 41 of 97 DIP patients (42%) (95% CI 32 to 52%), with Grade II abnormalities in most cases (Grade I=3; Grade II=32, Grade III=6) (Fig. 1). Patients with abnormal SPECT were similar to patients with normal SPECT as regards all socio-demographic variables, except for age (Table 3). In the logistic regression model a significant association was found only between abnormal SPECT DAT-SCAN and age (adjusted OR 1.05; 95% CI 1.01 to 1.10; p=0.01). In terms of neurological symptoms, patients with abnormal SPECT were not significantly different from patients with normal SPECT. The UPDRS III total score was higher in patients with abnormal SPECT than in those with normal SPECT, although this finding was of only borderline statistical significance (pb0.053) (Table 4). 4. Discussion The results of the present study show that one third of patients with schizophrenia receiving treatment with AP drugs suffered from DIP. Among the socio-demographic and clinical variables considered, only age, use of long-acting APs and a positive family history of parkinsonism were significantly associated with the development of DIP. Interestingly, a dopamine nigrostriatal terminal defect was observed in a relevant proportion of DIP patients, as around 40% of them showed abnormal SPECT findings. Apart from age, we failed to find any other significant differences between DIP patients with normal and abnormal SPECT. The finding of such a high prevalence of SPECT abnormalities among DIP patients is in line with two preliminary studies carried out in small and selected samples of psychiatric patients (Lorberboym et al., 2006; Tinazzi et al., 2008) and might challenge the accepted notion that DIP is caused only by dopamine receptor blockade, without SPECT abnormalities (Tolosa et al., 2003). SPECT imaging is a highly sensitive method for detecting presynaptic dopamine nigrostriatal dysfunction, and can be helpful in

M. Tinazzi et al. / Schizophrenia Research 139 (2012) 40 45 43 Table 1 Distribution of socio-demographic and clinical variables by diagnosis of DIP in patients with schizophrenia. DIP No (N=299) Yes (N=149) Sex Males 154 51.51 72 51.68 χ 2 =0.40 Females 145 48.49 77 51.68 p=0.526 Age 40 50 144 48.16 59 19.73 χ 2 =26.02 51 60 76 25.42 43 28.86 pb0.001 61 70 59 19.73 49 32.89 71+ 20 6.69 20 13.42 Physical illness None 163 54.52 73 48.99 χ 2 =8.40 Diabetes 16 5.35 5 3.36 p=0.135 Hypertension 59 19.73 29 19.46 Diab. and hypert. 17 5.69 9 6.04 CNS 10 3.34 14 9.40 Other 34 11.37 19 12.75 Family history of parkinsonism No 293 97.99 138 92.62 χ 2 =7.87 Yes 6 2.01 11 7.38 p=0.005 Length of illness 0 10 51 17.65 31 21.53 χ 2 =3.09 11 20 69 23.88 26 18.06 p=0.377 21 30 101 34.95 47 32.64 31+ 68 23.53 40 27.78 AP drugs in the past (No.) One 132 45.83 67 46.85 χ 2 =0.04 Two or more 156 54.17 76 53.15 p=0.842 Number of AP drugs at study entry One 231 77.26 107 71.81 χ 2 =2.15 Two 60 20.07 35 23.49 p=0.340 Three or more 8 2.68 7 4.70 Type of AP drugs First-generation 69 23.08 43 28.86 χ 2 =1.77 Second-generation 230 76.92 106 71.14 p=0.183 AP dose Standard 261 87.29 136 91.28 χ 2 =1.56 High 38 12.71 13 8.72 p=0.211 Long-acting AP No 264 88.29 120 80.54 χ 2 =4.88 Yes 35 11.71 29 19.46 p=0.027 Anticholinergic drugs No 253 84.62 123 82.55 χ 2 =0.31 Yes 46 15.38 26 17.45 p=0.575 Other psychotropic drugs None 125 41.81 69 46.31 χ 2 =2.30 BDZ 122 40.80 56 37.58 p=0.679 AE 31 10.37 12 8.05 BDZ+AE 17 5.69 8 5.37 Other 4 1.31 4 2.68 order to differentiate between pre-synaptic (often but not always degenerative) and post-synaptic forms of parkinsonism (Kägi et al., 2010). Therefore, our findings suggest that in DIP patients with normal SPECT, parkinsonism may be caused by AP-induced D2-receptor blockade only, whereas in those with abnormal SPECT, blockade of D2 receptors may coexist with a dopamine nigrostriatal defect. The challenging issue is what these SPECT abnormalities represent. One hypothesis is that SPECT abnormalities in DIP patients might reflect a functional change; that is AP drugs may cause downregulation of striatal DAT, giving rise to abnormal SPECT scans. However, few clinical and pharmacological observations support this hypothesis. A first consideration is that, although APs have a marked effect on the dopaminergic system of the brain, they have a negligible affinity for DAT, and chronic haloperidol or clozapine treatments do not induce changes in DAT density or affinity in rats (Valvhar and Hanbauer, 1993; Reader et al., 1998). Secondly, evidence in patients with schizophrenia suggests that there is no difference in striatal binding of DAT between antipsychotic-naïve patients, patients Table 2 Distribution of neurological symptoms by diagnosis of DIP in patients with schizophrenia. DIP No (N=299) Yes (N=149) Tremor No 262 87.63 48 32.21 χ 2 =143.24 Yes 37 12.37 101 67.79 p b0.001 Rigidity No 283 94.65 11 7.38 χ 2 =335.70 Yes 16 5.35 138 92.62 p b0.001 Bradykinesia No 275 91.97 9 6.04 χ 2 =316.44 Yes 24 8.03 140 93.96 p b0.001 Tardive dyskinesia No 274 91.64 109 73.15 χ 2 =27.39 Yes 25 8.36 40 26.85 p b0.001 Posture No 250 84.75 24 16.11 χ 2 =197.39 Yes 45 15.25 125 83.89 p b0.001 Facial expression No 207 70.17 13 8.72 χ 2 =149.51 Yes 88 29.83 136 91.28 p b0.001 Clinical asymmetry No 290 96.99 93 62.42 χ 2 =95.833 Yes 9 3.01 56 37.58 p b0.001 UPDRS III total score, mean (SD) 2.74 (4.35) 22.29 (11.56) z= 16.73 p b0.001 treated with risperidone, drug-free patients and controls (Reader et al., 1998). Another hypothesis is that SPECT abnormalities in DIP patients might reflect nigrostriatal degeneration. Although the crosssectional design of the present study does not allow us to draw any definitive conclusions in this regard, the observations from followup studies that DIP patients with SPECT or PET abnormalities showed progression in both the reduction of striatal DAT uptake and parkinsonian symptom severity, and that the use of low doses of L-dopa may improve motor symptoms in these patients, support the possibility of a dopaminergic neurodegeneration (Burn and Brooks, 1993; Tinazzi et al., 2009). We acknowledge, however, that longitudinal studies of DIP patients are needed to shed more light on this hypothesis. We acknowledge that our study presents a number of limitations. Lack of SPECT data on patients with schizophrenia and without DIP may weaken our conclusions: if SPECT alterations do reflect nigrostriatal degeneration, then we should expect a higher incidence in DIP than in non-dip patients. SPECT data for such a control group, however, were not needed according to our study design because the main aims of the present study were to analyze the prevalence of SPECT abnormalities in patients with schizophrenia and clinical signs of parkinsonism and hence to characterize which clinical and neurological features may differentiate DIP patients with SPECT abnormalities from DIP patients with no such abnormalities. Moreover, the use of visual assessment of SPECT images might have introduced some degree of subjectivity of interpretation. Although we acknowledge this limitation, we note that 38 of 41 abnormal SPECT images were severely abnormal, thus minimizing the risk of an erroneous rating. This point warrants further ad-hoc investigation using a semi-quantitative assessment method. There is no general consensus as to how the diagnosis of DIP should be made, and therefore in the present study we decided to use diagnostic criteria based on the main clinical diagnostic criteria of PD (Jankovic, 2008), as previously used in other similar studies (Lorberboym et al., 2006; Tinazzi et al., 2008). Study power is a crucial issue in clinical studies. The present study is the largest study in the field but, as expected, a number of patients

44 M. Tinazzi et al. / Schizophrenia Research 139 (2012) 40 45 Fig. 1. Representative examples of [ 123 I]-FP-CIT SPECT images in a DIP patient with normal DAT binding and in three DIP patients with Grade I, Grade II and Grade III SPECT abnormalities (see text for details). with schizophrenia and DIP refused to participate in the SPECT analysis. Even though this reduces the statistical power of the overall analysis, we found that patients who refused to participate were similar to those who agreed to undergo the SPECT scan, suggesting that Table 3 Distribution of socio-demographic and clinical variables by SPECT findings in patients with DIP and schizophrenia. [ 123 I]FP-CIT SPECT Normal (N=56) Abnormal (N=41) Sex Males 32 57.14 21 51.22 χ 2 =0.33 Females 24 42.86 20 48.78 p =0.563 Age 40 50 16 28.57 5 12.20 χ 2 =8.66 51 60 19 33.93 9 21.95 p =0.034 61 70 17 30.36 19 46.34 71+ 4 7.14 8 19.51 Physical illness None 25 44.64 23 56.10 χ 2 =6.52 Diabetes 1 1.79 2 4.88 p =0.259 Hypertension 11 19.64 6 14.63 Diab. and hypert. 3 5.36 1 2.44 CNS 4 7.14 6 14.63 Other 12 21.43 3 7.32 Family history of parkinsonism No 52 92.86 37 90.24 χ 2 =0.21 Yes 4 7.14 4 9.76 p =0.644 Length of illness 0 10 14 25.45 10 26.32 χ 2 =6.76 11 20 10 18.18 7 18.42 p =0.08 21 30 23 41.82 8 21.05 31+ 8 14.55 13 34.21 AP drugs in the past (No.) One 24 46.15 21 51.22 χ 2 =0.23 Two or more 28 53.85 20 48.78 p =0.627 Number of AP drugs at study entry One 41 73.21 29 70.73 χ 2 =2.80 Two 12 21.43 12 29.27 p =0.246 Three or more 3 5.36 0 Type of AP drugs First-generation 19 33.93 10 24.39 χ 2 =1.02 Second-generation 37 66.07 31 75.61 p =0.311 AP dose Standard 51 91.07 37 90.24 χ 2 =0.01 High 5 8.93 4 9.76 p =0.890 Long-acting AP No 44 78.57 36 87.80 χ 2 =1.39 Yes 12 21.43 5 12.20 p =0.237 Anticholinergic drugs No 45 80.36 37 90.24 χ 2 =1.76 Yes 11 19.64 4 9.76 p =0.183 Other psychotropic drugs None 30 53.57 23 56.10 χ 2 =6.28 BDZ 16 28.57 17 41.46 p =0.179 AE 7 12.50 1 2.44 BDZ+AE 2 3.57 0 Other 1 1.79 0 the real-world design of the study did not significantly affect the results. Finally, since this was an observational cross-sectional study, the potential for confounding factors cannot be ruled out. For example, the relationship between exposure to second-generation APs and DIP should be interpreted in the light of the fact that patients with extrapyramidal side effects are more likely to be treated with newer drugs, and therefore exposure to second-generation APs might be a proxy of the presence of extrapyramidal side effects. Similarly, whether the association between long-acting preparations and DIP is causative or an epiphenomenon remains to be established; it may simply reflect the practice of reserving these formulations for more severe patients who had already been unsuccessfully treated with several oral AP drugs and whose extrapyramidal side effects might date back to their use. This hypothesis is supported by recent evidence suggesting that long-acting AP drugs might have the edge in terms of efficacy over oral AP drugs (Leucht et al., 2011). Notwithstanding the foregoing limitations, our findings suggest that D2-receptor blockade may coexist with a dopamine nigrostriatal terminal defect, as assessed by [ 123 I]FP-CIT SPECT abnormalities, in a relevant proportion of DIP patients. These preliminary results in a large sample of schizophrenia patients need to be further investigated in longitudinal studies aimed at improving our understanding of the mechanisms of pre-synaptic abnormalities in DIP patients and identifying specific treatment strategies. Table 4 Distribution of neurological variables by SPECT findings in patients with DIP and schizophrenia. [ 123 I]FP-CIT SPECT Normal (N=56) Abnormal (N=41) Tremor No 17 30.36 11 26.83 χ 2 =0.14 Yes 39 69.64 30 73.17 pb0.705 Rigidity No 5 8.93 3 7.32 χ 2 =0.08 Yes 51 91.07 38 92.68 pb0.776 Bradykinesia No 2 3.57 1 2.44 χ 2 =0.101 Yes 54 96.43 40 97.56 pb0.750 Tardive diskynesia No 40 71.43 34 82.93 χ 2 =1.73 Yes 16 28.57 7 17.07 p=0.188 Posture No 12 21.43 4 9.76 χ 2 =2.341 Yes 44 78.57 37 90.24 p=0.126 Facial expression No 4 7.14 4 9.76 χ 2 =0.213 Yes 52 92.86 37 90.24 p=0.644 Clinical asymmetry No 38 67.86 21 51.22 χ 2 =2.74 Yes 18 32.14 20 48.78 pb0.097 UPDRS III total score, mean (SD) 20.92 (10.56) 26.97 (14.26) z= 1.92 pb0.053

M. Tinazzi et al. / Schizophrenia Research 139 (2012) 40 45 45 Role of funding source None. Contributors Study concept and design: M. Tinazzi, A. Cipriani, C. Barbui, T. Bovi Acquisition of data: A. Matinella, A. Cannas, P. Solla, A. Nicoletti, M. Zappia, L. Morgante, F. Morgante, C. Pacchetti, M. Sciarretta, C. Dallocchio, S. Rossi, M. Malentacchi, R. Ceravolo, D. Frosini, S. Sestini Analysis and interpretation of data: M. Tinazzi, A. Cipriani, C. Barbui, T. Bovi Drafting of the manuscript: M. Tinazzi, A. Cipriani, C. Barbui, T. Bovi Critical revision of the manuscript: A. Matinella, A. Cannas, P. Solla, A. Nicoletti, M. Zappia, L. Morgante, F. Morgante, C. Pacchetti, M. Sciarretta, C. Dallocchio, S. Rossi, M. Malentacchi, R. Ceravolo, D. Frosini, S. Sestini Statistical analysis: C. Barbui, A. Cipriani Conflict of interest Full financial disclosures for the previous 12 months: Dr. M. Tinazzi, L. Morgante, F. Morgante, M. Zappia and R. Ceravolo have received honoraria for lectures and educational activities from Boeringher Ingelheim, Glaxo Smithkline, Lundbeck, UCB pharma, Chiesi Farmaceutici, and Novartis. Dr. A. Cannas and C. Pacchetti have received honoraria for educational activities from Chiesi Farmaceutici, and Boeringher Ingelheim. Dr. A. Cipriani, A. Matinella, P. Solla, A. Nicoletti, M. Sciarretta, C. Dallocchio, S. Rossi, M. Malentacchi, D. Frosini, S. Sestini, T. Bovi and C. Barbui report no financial disclosures. Acknowledgment We thank Mr. Anthony Steele, former Verona University senior lecturer in Medical English for his invaluable assistance with the linguistic revision of this paper. List of contributors: Maria Giovanna Marrosu, Claudia Serra (Department of Cardiovascular and Neurological Sciences, Section of Neurology, University of Cagliari); Angela Di Stefano (Institute of Neurological Sciences, National Research Council, Section of Catania); Luca Antonina (Department GF Ingrassia, Section of Neurosciences, University of Catania); Sergio Baldari (Department of Radiological Sciences, University of Messina); Enrica Di Rosa (Department of Neurosciences, Psychiatric and Anaesthesiological Sciences, University of Messina); Duccio Volterrani (Unit of Nuclear Medicine, University of Pisa); Alberto De Capua (Department of Mental Health, Siena, Italy); Luca Burroni (Unit of Nuclear Medicine, Siena, Italy); Pia Luisia Aroasio, Silvia Barbieri (Department of Mental Health, Unit of Psychiatry, Oltrepò, Pavia, Italy); Paolo Orsi, Francesca Cavallin (Department of Applied Health and Psycho-behavioural Sciences, Section of Psychiatry, University of Pavia); Antonio Fiaschi (Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona); Giuseppe Moretto (Unit of Neurology, Verona, Italy); Francesca Girlanda, Michela Nosè (Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, University of Verona). 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