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 LETTERS TO THE EDITOR

The effect of quetiapine on auditory P300 response in patients with schizoaffective disorder: Preliminary study

Milena Korostenskaja, PhD

Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA

Kastytis Dapsys, MSc

Department of Electrophysiology, Republican Vilnius Psychiatric Hospital, Vilnius, Lithuania

Aldona Siurkute, MD, PhD

Department of Electrophysiology, Republican Vilnius Psychiatric Hospital, Clinic of Psychiatry, Vilnius University, Vilnius, Lithuania

Akvile Dudlauskaite, MSc

Department of Electrophysiology, Republican Vilnius Psychiatric Hospital, Vilnius, Lithuania

Audra Pragaraviciene, BSc

Department of Psychology and Didactics, Faculty of Pedagogy and Psychology, Vilnius Pedagogical University, Vilnius, Lithuania

Valentinas Maciulis, MD, PhD

Department of Electrophysiology, Republican Vilnius Psychiatric Hospital, Vilnius, Lithuania

Seppo Kähkönen, MD, PhD

BioMag Laboratory, Helsinki University Central Hospital, Helsinki, Finland

KEYWORDS: ERPs, P300, quetiapine, antipsychotics, schizophrenia

ANNALS OF CLINICAL PSYCHIATRY 2009;21(1):49–50

  TO THE EDITOR:

Abnormalities in attention, memory, and information processing are considered the primary deficits in schizophrenia. Event-related potential (ERP) P300 could reflect deficits in auditory information processing related to active attention in schizophrenia patients. The reduction in P300 amplitude and/or delay in latency are prominent findings in schizophrenia patients. Atypical antipsychotics tend to ameliorate the cognitive deficits that are apparent in this disease. However, the effects of antipsychotic drugs on neural aspects of cognitive dysfunction have not been consistent. Risperidone treatment has been shown to significantly reduce P300 latency.1 Further, in studies, clozapine increased P300 amplitudes.2 However, Gallinat et al3 could not find changes in P300 amplitude and latency during therapy with olanzapine or clozapine. Furthermore, perospiron failed to change P300 amplitude in schizophrenia patients after switching from previous antipsychotic medications.4 A number of studies have suggested that quetiapine, an atypical antipsychotic drug, may have beneficial effects on cognitive functioning in schizophrenic patients. No studies investigating the effect of quetiapine on ERPs have been published to date.

Our group aimed to investigate, for the first time, the effects of quetiapine (468.7 ± 143 mg/d) on auditory information processing by using auditory P300. We examined 7 patients with schizoaffective disorder, depressive type (F25.1) (5 women, 2 men; mean age, 36.71 ± 10.6 years) and 7 age- and sex-matched healthy controls (mean age 35.10 ± 9.8 years). Diagnoses were made according to the ICD-10, International Classification of Diseases.5 ERPs were elicited during an active auditory oddball paradigm (the deviant stimulus had 20% probability, 1000 Hz frequency, and 50 ms duration; the standard tone had 80% probability, 2000 Hz frequency, and 50 ms duration). Tones were delivered through the earphones at 60 dB. During the recording, 60 target stimuli were averaged. Patients were asked to mentally count the target stimuli. P300 was recorded before and after 2 weeks of treatment.

Digital filters were applied offline with passband 0.15 Hz to 30 Hz. P300 latency was determined at the Cz electrode site in response to the deviant tones. At these latencies, the peak amplitudes were determined from Fz, Cz, and Pz electrodes. Amplitudes were measured in relation to the 100 ms prestimulus baseline. Comparisons of P300 peak latencies were performed (1) between healthy controls and patients at baseline, (2) between healthy controls and patients after 2 weeks’ follow-up, and (3) between patients at baseline and after 2 weeks’ follow-up. Student t tests (paired and unpaired) were used for comparison.

Results of the study are presented in the TABLE. Baseline P300 latencies were significantly delayed in study patients compared with controls. Quetiapine did not change P300 amplitudes, but it normalized P300 latency. These results suggest that after 2 weeks of treatment, quetiapine could have a beneficial effect on speed of information processing in patients with schizoaffective disorder, as reflected in auditory P300 response. Previous studies with antipsychotic drugs such as olanzapine and risperidone failed to show changes in P300 after this treatment interval.6 Results of the current study suggest that quetiapine may act more quickly than other neuroleptics in ameliorating attentional dysfunction in patients with schizoaffective disorder. However, studies with a larger sample size must be conducted in order to confirm or reject the results of the current study.


TABLE

Amplitudes and latencies of P300 component* of healthy controls and patients at baseline and 2 weeks after quetiapine treatment

P300 parameters Healthy controls (n = 7) Patients (n = 7)
    At baseline After treatment
Latency, ms 320.8 ± 25.1 376.8 ± 33.9a 335.8 ± 30.2b
Amplitude, μV Fz 3.7 ± 5.4 4.1 ± 4.2 5.3 ± 6.3
  Cz 4.74 ± 6.74 4.3 ± 3.93 5.0 ± 5.4
  Pz 5.5 ± 6.5 3.2 ± 4.7 5.0 ± 5.9
*Mean ± standard deviation.
aP=.004, healthy controls compared with patients (unpaired t test).
bP=.028, patients at baseline compared with patients after 2 weeks of treatment (paired t test).

Acknowledgements

Dr. Korostenskaja is in the Department of Electrophysiology, Republican Vilnius Psychiatric Hospital, Vilnius, Lithuania, the BioMag Laboratory, Helsinki University Central Hospital, Helsinki, Finland, and the Cognitive Brain Research Unit, Department of Psychology, Helsinki University. Dr. Kähkönen is at the Cognitive Brain Research Unit, Department of Psychology, Helsinki University and the Pain Clinic, Department of Anesthesiology and Intensive Care, Helsinki University Central Hospital, both in Helsinki, Finland.

Disclosures

The authors report no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

    References

  1. Iwanami A, Okajima Y, Isono H, et al. Effects of risperidone on event-related potentials in schizophrenic patients. Pharmacopsychiatry. 2001;34:73–79.
  2. Niznikiewicz MA, Patel JK, McCarley R, et al. Clozapine action on auditory P3 response in schizophrenia. Schizophr Res. 2005;76:119–121.
  3. Gallinat J, Riedel M, Juckel G, et al. P300 and symptom improvement in schizophrenia. Psychopharmacology (Berl). 2001;158:55–65.
  4. Araki T, Kasai K, Rogers MA, et al. The effect of perospirone on auditory P300 in schizophrenia: a preliminary study. Prog Neuropsychopharmacol Biol Psychiatry. 2006;30:1083–1090.
  5.  World Health Organization. International Statistical Classification of Diseases and Health Related Problems, 10th revision, 2nd ed. Geneva: World Health Organization; 2004.
  6. Korostenskaja M, Dapsys K, Siurkute A, et al. Effects of olanzapine on auditory P300 and mismatch negativity (MMN) in schizophrenia spectrum disorders. Prog Neuropsychopharmacol Biol Psychiatry. 2005;29:543–548.

CORRESPONDENCE: Milena Korostenskaja, PhD, Division of Neurology MLC 2015, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039 USA. E-MAIL: milena.korostenskaja@gmail.com