Clinical Phenotypes of Anorexia Nervosa: Mathematical Models Based on Latent Class Analysis of Psychopathological...

Anorexia nervosa (AN) is characterized by heterogeneous clinical manifestations, which complicates diagnosis and treatment. It is important to define the clinical variants and therapeutic targets for AN.

To identify empirical patient phenotypes within the AN diagnostic category using Latent Class Analysis (LCA) of clinically assessed psychopathological symptoms.

Psychiatrists clinically assessed psychopathological symptoms of AN using an original checklist (57 symptoms in total) and the Mini-International Neuropsychiatric Interview (M.I.N.I.) was used to identify mental disorders. Patients completed the Symptom Check List-90-Revised questionnaire (SCL-90-R) to self-assess psychopathological symptoms and distress. Clinically homogeneous patient subgroups were identified using LCA.

A total of 115 patients with AN were examined. Based on the LCA, four patient groups (C1-C4) were identified, with high classification certainty (R²=0.908), model significance (p<0.001), and clear separation of the latent groups (class separation index = 0.957). ED-related symptoms were key determinants of class formation only in 68 patients (59%) - those in C1 and C3. No statistically significant differences were found between classes on any SCL-90-R subscales or most M.I.N.I. diagnoses. In C1 (n=41), core ED symptoms dominated: dysmorphophobia, fears related to eating, weight gain, loss of control. In C2 (n=39), low frequencies are observed for core ED symptoms; this group was characterized by a high incidence of sleep disturbances, anxiety, apathy, melancholy, and anhedonia. C3 (n=27) represents a polymorphic clinical profile with a combination of core ED symptoms, affective symptoms, thought disorders, cognitive impairments, and sleep disturbances. C4 (n=8) was defined by the presence of hypochondriacal concerns, somatoform autonomic symptoms, and apathy; none of the core ED symptoms were typical for C4.

Four empirically derived clinical phenotypes of AN were identified, each characterized by a distinct symptomatic profile. Each phenotype was defined by specific combinations of core ED symptoms and general psychopathological manifestations.