Despite a long psychological discussion on the inconsistency and fragmentation in self-appraisals as factors of neuroses and personality disorders (Horney, 1991, Lynch, 2014) classical psychodiagnostic considers response inconsistency as an indicator of protocol invalidity only.

Using MMPI-2 True and Variable Response Inconsistency scales (TRIN, VRIN), we suggest that the inconsistency (within normative range) is related to poorer psychological well-being in the normative sample and is higher in affective disorders.

To study the relationship between response inconsistency and psychological well-being.

In total, 1443 healthy controls and 190 patients with mental illnesses (50 with affective disorders, 21 with addictions, 73 with schizophrenia and schizotypal disorder, 46 with adjustment disorder) who scored within normative range on all the validity scales of the Russian version of MMPI-2 participated in the study.

In the normative sample, TRIN and VRIN correlated with social and emotional alienation as well as conative lack of ego mastery (r = .27–.33) and were higher in affective disorders (P < .05) and in patients having symptoms of personality disorders (as appraised by their doctors). In patients with affective disorders and adjustment disorders, they were related to higher likelihood of invalidity due to mental illness.

Response incoherence within normative range is a sign of poorer well-being in the normative sample (in the form of fatigue, apathy, feelings of excessive strain, lack of understanding from others and injustice). In line with psychological theories of self-fragmentation, incoherence is related to affective disorders (and poorer adjustment to them) and symptoms of personality disorders.

The authors have not supplied their declaration of competing interest.