Clinical subtypes of severe bipolar mixed states.
OBJECTIVE
The aim of the present study was to identify different clinical subtypes in severe, treatment resistant bipolar mixed state (MS).


METHODS
The sample comprised 202 Bipolar I patients currently in MS referred for an Electro-convulsive Therapy (ECT) trial and evaluated in the first week of hospitalization and one week after the ECT course. Principal component factor analysis (PCA) followed by Varimax rotation was performed on 21 non-overlapping items selected from Hamilton rating-scale for depression (HAMD) and from Young mania rating-scale (YMRS) at baseline evaluation. Cluster subtypes derived from the factor scores were compared in clinical variables and final HAMD, YMRS, Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression (CGI) scores.


RESULTS
The principal-component analysis extracted 6 interpretable factors explaining 55.9% of the total variance. Cluster analysis identified four groups, including respectively 63 (31.2%) subjects with Agitated-Irritable Mixed-Depression, 59 (29.2%) with Psychotic Mixed-Mania, 17 (8.5%) with Anxious-Irritable-Psychotic Mixed-Mania, and 63 (31.2%) with Retarded-Psychotic Mixed-Depression. The four clusters were statistically distinct and did not show significant overlap in the main symptomatological presentation. Cluster subtypes reported differences in number of past mood episodes, duration of the current episode, suicide attempts, lifetime comorbidity with panic and eating disorders, baseline and final rating-scale scores and rate of remission after ECT trial.


CONCLUSIONS
Our study indicates that, at least in severe treatment resistant MS, multiple depressive and manic subtypes can be observed with substantial differences in terms of clinical presentation, course, associated comorbidities and treatment response.
Clinica Psichiatrica, Dipartmento di Medicina Sperimentale, University of Pisa, Pisa, Italy. Electronic address: gperugi@med.unipi.it.
Giulio
G
Perugi
Pierpaolo
P
Medda
João
J
Reis
Salvatore
S
Rizzato
Michela
M
Giorgi Mariani
Mauro
M
Mauri
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000523:psychology; D001714:Bipolar Disorder / Q000145:classification* / Q000523:psychology / Q000628:therapy; D003863:Depression / Q000523:psychology; D004565:Electroconvulsive Therapy; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D016896:Treatment Outcome; D055815:Young Adult
Bipolar disorder; Cluster analysis; Electro-convulsive therapy; HAMD; Mixed state; YMRS