Attentional standardised composite score: Standardised speed of performance score. Higher Score=better performance. Score range minus infinity to plus infinity. Measured at baseline (before study drug administration) and in Period 1 at 3 visits,(post 1),(post 2),(post 3), in a 5-day (maximum 8 day) period. (Last test day not earlier than after 10 days of randomised)and in Period 2 at 3 visits,(post 1),(post 2),(post 3), in a 5-day (maximum 8 day) period. Last test day not earlier than after 10 days of crossover treatment.

The per protocol set (PPS) is a subset of the FAS consisting of patients who fulfilled all inclusion criteria but none of the exclusion criteria, complied with study medication dosing scheme, did not violate any of the study restrictions and completed the study without protocol violation.

TSQM is a 14-item questionnaire with 4 sub-scales: effectiveness of the medication; treatment side effects; convenience of the medication; global satisfaction with the medication. Scale range 0-100 for each sub-scale, higher=greater satisfaction/milder side effects/greater convenience/greater overall satisfaction.

There are 2 measurement, (after the start of taking study drug) one at end of period 1 and one at end of period 2. That is one measurement per patient per treatment. The mean of all the patients is presented, one mean value per treatment group.

Full Analysis Set (FAS)used for efficacy analysis included all patients who in both study periods, received at least 1 dose of investigational product and for whom post-dose efficacy data was available.

International Shopping List Task (ISLT): measures reasoning and problem solving. Min=minus infinity, max=plus infinity, higher score=better performance. Groton Maze Learning Test (GMLT): measures reasoning and problem solving. Min=minus infinity, max=plus infinity, lower score=better performance. Lower=better performance. One Back memory task (ONB: measures working memory, min=minus infinity, max=plus infinity, lower score=better performance.

Per Protocol (PPS), subset of the FAS consisting of patients who fulfilled all of inclusion but none of exclusion criteria, complied with study medication dosing, did not violate any of the restrictions and completed the study without protocol violation.

The modified Bond-Lader VAS: The degree of sedation was marked by the patient on a 100 mm VAS ranging between Alert (=0 mm) and Drowsy (=100 mm). The marked length in millimetres.

There are 3 assessments made in each period (post 1, 2 and 3 for each period). That is three measurements per patient per treatment. The mean is an overall mean of all the recordings in all patients, one mean value per treatment group.

The full analysis set (FAS) used for analysis of efficacy included all patients who, in both study periods, received at least one dose of investigational product and for whom post-dose efficacy data are available in both periods.

Stanford Sleepiness Scale: The sleepiness was assessed by the patient on a 7 item rating scale ranging from 1 (Feeling active and vital) to 7 (Almost in reverie).

There are 3 assessments made in each period (post 1, 2 and 3 for each period). That is three measurements per patient per treatment. The mean is an overall mean of all the recordings in all patients, one mean value per treatment group.

The full analysis set (FAS) used for analysis of efficacy included all patients who, in both study periods, received at least one dose of investigational product and for whom post-dose efficacy data are available in both periods.

The number of patients who dropped out was counted.

The Safety analysis set was used, that is all patients who received at least one dose of study medication and for whom any post-dose safety data are available were included in the safety set.

The ratio was derived as individual plasma concentration of quetiapine divided by the plasma concentration of nor-quetiapine. The mean ratio was derived for each treatment, XR and IR, respectively.

21 patients for the FAS were analysed. This outcome measure was introduced as a protocol amendment after study start and plasma concentration was not measured in all patients. FAS is all patients who, in both study periods, received at least one dose of investigational product and for whom post-dose efficacy data are available in both periods.