The effects of stress-tension on depression and anxiety symptoms: evidence from a novel twin modelling analysis.
Negative mood states are composed of symptoms of depression and anxiety, and by a third factor related to stress, tension and irritability. We sought to clarify the nature of the relationships between the factors by studying twin pairs.



A total of 503 monozygotic twin pairs completed the Depression Anxiety Stress Scales (DASS), an instrument that assesses symptoms of depression, anxiety and stress-tension. We applied a recently developed twin regression methodology - Inference about Causation from Examination of FAmiliaL CONfounding (ICE FALCON) - to test for evidence consistent with the existence of 'causal' influences between the DASS factors.



There was evidence consistent with the stress-tension factor having a causal influence on both the depression (p < 0.0001) and anxiety factors (p = 0.001), and for the depression factor having a causal influence on the anxiety factor (p < 0.001).



Our findings suggest a critical role for stress-tension in the structure of negative mood states, and that interventions that target it may be particularly effective in reducing depression and anxiety symptoms.
Orygen, The National Centre of Excellence in Youth Mental Health,Melbourne,Australia.
C G
CG
Davey
Adult Mental Health Unit,Parc Taulí University Hospital,Sabadell,Spain.
C
C
López-Solà
Centre for Epidemiology and Biostatistics, Melbourne School of Population Health, The University of Melbourne,Melbourne,Australia.
M
M
Bui
Centre for Epidemiology and Biostatistics, Melbourne School of Population Health, The University of Melbourne,Melbourne,Australia.
J L
JL
Hopper
Department of Psychiatry,Melbourne Neuropsychiatry Centre, The University of Melbourne,Melbourne,Australia.
C
C
Pantelis
Programa de Transtornos Obsessivo-Compulsivos e de Ansiedade,Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro (UFRJ),Rio de Janeiro,Brazil.
L F
LF
Fontenelle
Department of Psychiatry,Melbourne Neuropsychiatry Centre, The University of Melbourne,Melbourne,Australia.
B J
BJ
Harrison
D000328:Adult; D001007:Anxiety / Q000523:psychology*; D015984:Causality; D003863:Depression / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D013315:Stress, Psychological / Q000523:psychology*; D014430:Twins, Monozygotic
Anxiety; depression; stress; temperament; twin studies