Problematic assumptions have slowed down depression research: Why symptoms, not syndromes are the way forward

Frontiers in Psychology

Volumn 6, Issue MAR, 2015, Pages

  Fried, Eiko I ^a  

^a UNIVERSITY OF LEUVEN   (Belgium)

Author keywords

Depression symptoms; DSM; Essentialism; Major depression; Networks; Nosology

Indexed keywords

EID: 84926643596     PISSN: None     EISSN: 16641078     Source Type: Journal    
DOI: 10.3389/fpsyg.2015.00309     Document Type: Review

References (120)

1. Adriaens, P. R., and De Block, A. (2013). Why we essentialize mental disorders. J. Med. Philos. 38, 107-127. doi: 10.1093/jmp/jht008
2. Aggen, S. H., Neale, M. C., and Kendler, K. S. (2005). DSM criteria for major depression: evaluating symptom patterns using latent-trait item response models. Psychol. Med. 35, 475-487. doi: 10.1017/S0033291704003563
3. Allport, G. (1954). The Nature of Prejudice . Reaeding, MA: Addison-Wesley.
4. Andreasen, N. (2001). Brave New Brain: Conquering Mental Illness in the Era of the Genome . New York, NY: Oxford University Press.
5. APA. (1980). Diagnostic and Statistical Manual of Mental Disorders , 3rd Edn. Washington, DC: American Psychiatric Association.
6. APA. (1994). The Diagnostic and Statistical Manual of Mental Disorders , 4th Edn. Washington, DC: American Psychiatric Association.
7. APA. (2013). Diagnostic and Statistical Manual of Mental Disorders , 5th Edn. Washington, DC: American Psychiatric Association.
8. Barlow, D. H., Allen, L. B., and Choate, M. L. (2004). Toward a unified treatment for emotional disorders. Behav. Ther. 35, 205-230. doi: 10.1016/S0005-7894(04)80036-4
9. Beck, A., Brown, G., and Berchick, R. (1990). Relationship between hopelessness and ultimate suicide: a replication with psychiatric outpatients. Am. J. Psychiatry 147, 190-195. doi: 10.1176/ajp.147.2.190
10. Beck, A., Rush, A. J., Shaw, F. S., and Emery, G. (1979). Cognitive Therapy of Depression . New York, NY: Guilford Press.
11. Beck, A. T., Ward, C. H., Mendelson, M., Mock, J., and Erbaugh, J. (1961). An inventory for measuring depression. Arch. Gen. Psychiatry 4, 561-571. doi: 10.1001/archpsyc.1961.01710120031004
12. Bollen, K. A. (1989). Structural Equations with Latent Variables . New York, NY: Wiley. doi: 10.1002/9781118619179
13. Borsboom, D., and Cramer, A. O. J. (2013). Network analysis: an integrative approach to the structure of psychopathology. Annu. Rev. Clin. Psychol. 9, 91-121. doi: 10.1146/annurev-clinpsy-050212-185608
14. Borsboom, D., Cramer, A. O. J., Schmittmann, V. D., Epskamp, S., and Waldorp, L. J. (2011). The small world of psychopathology. PLoS ONE 6:e27407. doi: 10.1371/journal.pone.0027407
15. Boyd, R. (1991). Realism, anti-foundationalism and the enthusiasm for natural kinds. Philos. Stud. 61, 127-148. doi: 10.1007/BF00385837
16. Boyd, R. (1999). "Homeostasis, species, and higher taxa," in Species: New Interdisciplinary Essays , ed. R. A. Wilson (Cambridge, MA: A Bradford Book/The MIT Press), 141-185.
17. Bringmann, L. F., Lemmens, L. H. J. M., Huibers, M. J. H., Borsboom, D., and Tuerlinckx, F. (2014). Revealing the dynamic network structure of the Beck Depression Inventory-II. Psychol. Med . 45, 747-757. doi: 10.1017/S0033291714001809
18. Bringmann, L. F., Vissers, N., Wichers, M. C., Geschwind, N., Kuppens, P., Peeters, F.,et al. (2013). A network approach to psychopathology: new insights into clinical longitudinal data. PLoS ONE 8:e60188. doi: 10.1371/journal.pone.0060188
19. Brooks, D. (2013). Heroes of uncertainty. New York Times . Available at: http://www.nytimes.com/2013/05/28/opinion/brooks-heroes-of-uncertainty.html?_r=3D2&
20. Brown, G. K., Beck, A., Steer, R. A., and Grisham, J. R. (2000). Risk factors for suicide in psychiatric outpatients: a 20-year prospective study. J. Consult. Clin. Psychol. 68, 371-377. doi: 10.1037/0022-006X.68.3.371
21. Costello, C. (1993). "The advantages of the symptom approach to depression," in Symptoms of Depression , ed. C. Costello (New York, NY: John Wiley and Sons), 1-21.
22. Cramer, A. O. J., Borsboom, D., Aggen, S. H., and Kendler, K. S. (2013). The pathoplasticity of dysphoric episodes: differential impact of stressful life events on the pattern of depressive symptom inter-correlations. Psychol. Med. 42, 957-965. doi: 10.1017/S003329171100211X
23. Cramer, A. O. J., Waldorp, L. J., van der Maas, H. L. J., and Borsboom, D. (2010). Comorbidity: a network perspective. Behav. Brain Sci. 33, 137-150. doi: 10.1017/S0140525X09991567
24. Daly, J., Ripke, S., Lewis, C. M., Lin, D., Wray, N. R., Neale, B.,et al. (2013). A mega-analysis of genome-wide association studies for major depressive disorder. Mol. Psychiatry 18, 497-511. doi: 10.1038/mp.2012.21.A
25. de Wild-Hartmann, J. A., Wichers, M. C., van Bemmel, A. L., Derom, C., Thiery, E., Jacobs, N.,et al. (2013). Day-to-day associations between subjective sleep and affect in regard to future depression in a female population-based sample. Br. J. Psychiatry 202, 407-412. doi: 10.1192/bjp.bp.112.123794
26. Dombrovski, A. Y., Mulsant, B. H., Houck, P. R., Mazumdar, S., Lenze, E. J., Andreescu, C.,et al. (2007). Residual symptoms and recurrence during maintenance treatment of late-life depression. J. Affect. Disord. 103, 77-82. doi: 10.1016/j.jad.2007.01.020
27. Durmer, J., and Dinges, D. (2005). Neurocognitive consequences of sleep deprivation. Semin. Neurol. 25, 117-129. doi: 10.1055/s-2005-867080
28. Ereshefsky, M. (2007). "Species," in The Stanford Encyclopedia of Philosophy (Summer 2007 Edition), ed. E. N. Zalte (Standford, CA: Stanford Encyclopedia of Philosophy). Available at: http://plato.stanford.edu/entries/species/
29. Fairclough, S. H., and Graham, R. (1999). Impairment of driving performance caused by sleep deprivation or alcohol: a comparative study. Hum. Factors 41, 118-128. doi: 10.1518/001872099779577336
30. Faravelli, C., Servi, P., Arends, J., and Strik, W. (1996). Number of symptoms, quantification, and qualification of depression. Compr. Psychiatry 37, 307-315. doi: 10.1016/S0010-440X(96)90011-5
31. Fawcett, J., Scheftner, W. A., Fogg, L., Clark, D. C., Young, M. A., Hedeker, D.,et al. (1990). Time-related predictors of suicide in major affective disorder. Am. J. Psychiatry 147, 1189-1194. doi: 10.1176/ajp.147.9.1189
32. Ferentinos, P., Kontaxakis, V., Havaki-Kontaxaki, B., Paparrigopoulos, T., Dikeos, D., Ktonas, P.,et al. (2009). Sleep disturbances in relation to fatigue in major depression. J. Psychosom. Res. 66, 37-42. doi: 10.1016/j.jpsychores.2008. 07.009
33. Fine, A. (1984). "The natural ontological attitude," in Scientific Realism , ed. J. Leplin (Berkeley, CA: University of California Press), 83-107.
34. Frewen, P. A., Allen, S. L., Lanius, R. A., and Neufeld, R. W. J. (2012). Perceived causal relations: novel methodology for assessing client attributions about causal associations between variables including symptoms and functional impairment. Assessment 19, 480-93. doi: 10.1177/1073191111418297
35. Frewen, P. A., Schmittmann, V. D., Bringmann, L. F., and Borsboom, D. (2013). Perceived causal relations between anxiety, posttraumatic stress and depression: extension to moderation, mediation, and network analysis. Eur. J. Psychotraumatol. 4, 1-14. doi: 10.3402/ejpt.v4i0.20656
36. Fried, E. I., Bockting, C., Arjadi, R., Borsboom, D., Tuerlinckx, F., Cramer, A.,et al. (2015). From loss to loneliness: the relationship between bereavement and depressive symptoms. J. Abnorm. Psychol. 1-10. doi: 10.1037/abn0000028 [Epub ahead of print].
37. Fried, E. I., and Nesse, R. M. (2014). The impact of individual depressive symptoms on impairment of psychosocial functioning. PLoS ONE 9:e90311. doi: 10.1371/journal.pone.0090311
38. Fried, E. I., and Nesse, R. M. (2015). Depression is not a consistent syndrome: an investigation of unique symptom patterns in the STAR*D study. J. Affect. Disord. 96-102. doi: 10.1016/j.jad.2014.10.010 [Epub ahead of print].
39. Fried, E. I., Nesse, R. M., Zivin, K., Guille, C., and Sen, S. (2014). Depression is more than the sum score of its parts: individual DSM symptoms have different risk factors. Psychol. Med . 44, 2067-2076. doi: 10.1017/S0033291713002900
40. Gelman, S. A. (2009). Learning from others: children's construction of concepts. Annu. Rev. Psychol. 60, 115-140. doi: 10.1146/annurev.psych.59.103006.093659
41. Goekoop, R., and Goekoop, J. G. (2014). A network view on psychiatric disorders: network clusters of symptoms as elementary syndromes of psychopathology. PLoS ONE 9:e112734. doi: 10.1371/journal.pone.0112734
42. Grados, M. A., Specht, M. W., Sung, H. -M., and Fortune, D. (2013). Glutamate drugs and pharmacogenetics of OCD: a pathway-based exploratory approach. Expert Opin. Drug Discov. 8, 1515-1527. doi: 10.1517/17460441.2013.845553
43. Grebb, J. A., and Carlsen, A. (2009). "Introduction and considerations for a brain-based diagnostic system in psychiatry," in Comprehensive Textbook of Psychiatry , eds. B. Sadock, V. Sadock, P. Ruiz, and H. Kaplan (Philadelphia: Wolters Kluwer Health/Lippincott Williams), 1-4.
44. Guze, S. (1992). Why Psychiatry Is a Branch of Medicine . Oxford: Oxford University Press.
45. Hamilton, M. (1960). A rating scale for depression. J. Neurol. Neurosurg. Psychiatry 23, 56-62. doi: 10.1136/jnnp.23.1.56
46. Haslam, N., and Ernst, D. (2002). Essentialist beliefs about mental disorders. J. Soc. Clin. Psychol. 21, 628-644. doi: 10.1521/jscp.21.6.628.22793
47. Haslam, N., Rothschild, L., and Ernst, D. (2000). Essentialist beliefs about social categories. Br. J. Soc. Psychol. 39(Pt 1), 113-127. doi: 10.1348/014466600164363
48. Hasler, G., Drevets, W. C., Manji, H. K., and Charney, D. S. (2004). Discovering endophenotypes for major depression. Neuropsychopharmacology 29, 1765-1781. doi: 10.1038/sj.npp.1300506
49. Hek, K., Demirkan, A., Lahti, J., and Terracciano, A. (2013). A genome-wide association study of depressive symptoms. Biol. Psychiatry 73, 667-678. doi: 10.1016/j.biopsych.2012.09.033
50. Hofmann, S. G. (2014). Toward a cognitive-behavioral classification system for mental disorders. Behav. Ther. 45, 576-587. doi: 10.1016/j.beth.2014. 03.001
51. Holland, P., and Rosenbaum, P. (1986). Conditional association and unidimensionality in monotone latent variable models. Ann. Statist. 14, 1523-1543. doi: 10.1214/aos/1176350174
52. Hooper, D., Coughlan, J., and Mullen, M. (2008). Structural equation modeling: guidelines for determining model fit. Electron. J. Bus. Res. Methods 6, 53-60.
53. Hyland, M. E. (2011). The Origins of Health and Disease . Cambridge: Cambridge University Press. doi: 10.1017/CBO9780511976216
54. Insel, T. R. (2013). Transforming Diagnosis. The National Institute of Mental Health . Available at: http://www.nimh.nih.gov/about/director/2013/transforming-diagnosis.shtmlabout/director/
55. Kapur, S., Phillips, A. G., and Insel, T. R. (2012). Why has it taken so long for biological psychiatry to develop clinical tests and what to do about it? Mol. Psychiatry 17, 1174-1179. doi: 10.1038/mp.2012.105
56. Keller, M. C., Neale, M. C., and Kendler, K. S. (2007). Association of different adverse life events with distinct patterns of depressive symptoms. Am. J. Psychiatry 164, 1521-1529. doi: 10.1176/appi.ajp.2007.06091564
57. Keller, M. C., and Nesse, R. M. (2006). The evolutionary significance of depressive symptoms: different adverse situations lead to different depressive symptom patterns. J. Pers. Soc. Psychol. 91, 316-330. doi: 10.1037/0022-3514.91. 2.316
58. Kendell, R., and Jablensky, A. (2003). Distinguishing between the validity and utility of psychiatric diagnoses. Am. J. Psychiatry 160. 4-12. doi: 10.1176/appi.ajp.160.1.4
59. Kendler, K. S. (2005). "A gene for...": the nature of gene action in psychiatric disorders. Am. J. Psychiatry 162, 1243-1252. doi: 10.1176/appi.ajp.162.7.1243
60. Kendler, K. S., Aggen, S. H., and Neale, M. C. (2013). Evidence for multiple genetic factors underlying DSM-IV criteria for major depression. Am. J. Psychiatry 70, 599-607. doi: 10.1001/jamapsychiatry.2013.751
61. Kendler, K. S., and Baker, J. H. (2007). Genetic influences on measures of the environment: a systematic review. Psychol. Med. 37, 615-626. doi: 10.1017/S0033291706009524
62. Kendler, K. S., Zachar, P., and Craver, C. (2010). What kinds of things are psychiatric disorders? Psychol. Med. 41, 1143-1150. doi: 10.1017/S0033291710001844
63. Kessler, R. C., Berglund, P., Demler, O., Jin, R., Koretz, D., Merikangas, K. R.,et al. (2003). The epidemiology of major depressive disorder: results from the National Comorbidity Survey Replication (NCS-R). JAMA 289, 3095-3105. doi: 10.1001/jama.289.23.3095
64. Kessler, R. C., Chiu, W. T., Demler, O., Merikangas, K. R., and Walters, E. E. (2005). Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the National Comorbidity Survey Replication. Arch. Gen. Psychiatry 62, 617-627. doi: 10.1001/archpsyc.62.6.617
65. Khan, A., Khan, S., and Brown, W. A. (2002). Are placebo controls necessary to test new antidepressants and anxiolytics? Int. J. Neuropsychopharmacol. 5, 193-197. doi: 10.1017/S1461145702002912
66. Kirsch, I., Deacon, B. J., Huedo-Medina, T. B., Scoboria, A., Moore, T. J., and Johnson, B. T. (2008). Initial severity and antidepressant benefits: a meta-analysis of data submitted to the Food and Drug Administration. PLoS Med . 5:e45. doi: 10.1371/journal.pmed.0050045
67. Klerman, G. (1978). "The evolution of a scientific nosology," in Schizophrenia: science and practice , ed. J. Shershow (Cambridge, MA: Harvard University Press), 99-121.
68. Kramer, I., Simons, C., Hartmann, J. A., Menne-Lothmann, C., Viechtbauer, W., Peeters, F.,et al. (2014). A therapeutic application of the experience sampling method in the treatment of depression: a randomized controlled trial. World Psychiatry 13, 68-77. doi: 10.1002/wps.20090
69. Kuo, W.-H., Gallo, J. J., and Eaton, W. W. (2004). Hopelessness, depression, substance disorder, and suicidality-a 13-year community-based study. Soc. Psychiatry Psychiatr. Epidemiol. 39, 497-501. doi: 10.1007/s00127-004-0775-z
70. Kupfer, D. J. (2013). Field Trial Results Guide DSM Recommendations. Huffingt. Post . Available at: http://www.huffingtonpost.com/david-j-kupfer-md/dsm-5_b_2083092.html
71. Kupfer, D. J., First, M. B., and Regier, D. A. (2002). A Research Agenda for DSM V . Washington, DC: American Psychiatric Association.
72. Lee, S. H., Ripke, S., Neale, B. M., Faraone, S. V., Purcell, S. M., Perlis, R. H.,et al. (2013). Genetic relationship between five psychiatric disorders estimated from genome-wide SNPs. Nat. Genet. 45, 984-994. doi: 10.1038/ng.2711
73. Lewis, C. M., Ng, M. Y., Butler, A. W., Cohen-Woods, S., Uher, R., Pirlo, K.,et al. (2010). Genome-wide association study of major recurrent depression in the U.K. population. Am. J. Psychiatry 167, 949-957. doi: 10.1176/appi.ajp.2010.09091380
74. Lieberman, J. (2013). Nothing to be defensive about. Psychiatry News . doi: 10.1176/appi.pn.2013.7b19
75. Lilienfeld, S. O. (2014). DSM-5: Centripetal scientific and centrifugal. Clin. Psychol. Sci. Pract. 21, 269-279 doi: 10.1111/cpsp.12075
76. Lux, V., and Kendler, K. S. (2010). Deconstructing major depression: a validation study of the DSM-IV symptomatic criteria. Psychol. Med. 40, 1679-1690. doi: 10.1017/S0033291709992157
77. Ma, S. H., and Teasdale, J. D. (2004). Mindfulness-based cognitive therapy for depression: replication and exploration of differential relapse prevention effects. J. Consult. Clin. Psychol. 72, 31-40. doi: 10.1037/0022-006X.72.1.31
78. Markon, K. E., Chmielewski, M., and Miller, C. J. (2011). The reliability and validity of discrete and continuous measures of psychopathology: a quantitative review. Psychol. Bull. 137, 856-879. doi: 10.1037/a0023678
79. McClintock, S. M., Husain, M. M., Greer, T. L., and Cullum, C. M. (2010). Association between depression severity and neurocognitive function in major depressive disorder: a review and synthesis. Neuropsychology 24, 9-34. doi: 10.1037/a0017336
80. Mineka, S., Watson, D., and Clark, L. A. (1998). Comorbidity of anxiety and unipolar mood disorders. Annu. Rev. Psychol. 49, 377-412. doi: 10.1146/annurev.psych.49.1.377
81. Myung, W., Song, J., Lim, S.-W., Won, H.-H., Kim, S., Lee, Y.,et al. (2012). Genetic association study of individual symptoms in depression. Psychiatry Res. 198, 400-406. doi: 10.1016/j.psychres.2011.12.037
82. Olbert, C. M., Gala, G. J., and Tupler, L. A. (2014). Quantifying heterogeneity attributable to polythetic diagnostic criteria: theoretical framework and empirical application. J. Abnorm. Psychol. 123, 452-462. doi: 10.1037/a0036068
83. Opsahl, T., Agneessens, F., and Skvoretz, J. (2010). Node centrality in weighted networks: Generalizing degree and shortest paths. Soc. Networks 32, 245-251. doi: 10.1016/j.socnet.2010.03.006
84. Parker, G. (2005). Beyond major depression. Psychol. Med. 35, 467-474. doi: 10.1017/S0033291704004210
85. Pe, M. L., Kircanski, K., Thompson, R. J., Bringmann, L. F., Tuerlinckx, F., Mestdagh, M.,et al. (2014). Emotion-Network density in major depressive disorder. Clin. Psychol. Sci. 3, 292-300. doi: 10.1177/2167702614540645
86. Persons, J. B. (1986). The advantages of studying psychological phenomena rather than psychiatric diagnoses. Am. Psychol. 41, 1252-1260. doi: 10.1037/0003-066X.41.11.1252
87. Pigott, H. E., Leventhal, A. M., Alter, G. S., and Boren, J. J. (2010). Efficacy and effectiveness of antidepressants: current status of research. Psychother. Psychosom. 79, 267-279. doi: 10.1159/000318293
88. Pilcher, J. J., and Huffcutt, A. I. (1996). Effects of sleep deprivation on performance: a meta-analysis. Sleep 19, 318-326
89. Pincus, H. A., Davis, W. W., and McQueen, L. E. (1999). "Subthreshold" mental disorders. a review and synthesis of studies on minor depression and other "brand names".Br. J. Psychiatry 174, 288-296. doi: 10.1192/bjp.174.4.288
90. Prentice, D. A., and Miller, D. T. (2007). Psychological essentialism of human categories. Curr. Dir. Psychol. Sci. 16, 202-206. doi: 10.1111/j.1467-8721.2007.00504.x
91. Purcell, S. M., Wray, N. R., Stone, J. L., Visscher, P. M., O'Donovan, M. C., Sullivan, P. F.,et al. (2009). Common polygenic variation contributes to risk of schizophrenia and bipolar disorder. Nature 460, 748-752. doi: 10.1038/nature08185
92. Reardon, S. (2014). NIH rethinks psychiatry trials. Nature 507, 288. doi: 10.1038/507288a
93. Regier, D. A., Narrow, W. E., Clarke, D. E., Kraemer, H. C., Kuramoto, S. J., Kuhl, E. A.,et al. (2013). DSM-5 field trials in the United States and Canada, Part II: test-retest reliability of selected categorical diagnoses. Am. J. Psychiatry 170, 59-70. doi: 10.1176/appi.ajp.2012.12070999
94. Riaza Bermudo-Soriano, C., Perez-Rodriguez, M. M., Vaquero-Lorenzo, C., and Baca-Garcia, E. (2012). New perspectives in glutamate and anxiety. Pharmacol. Biochem. Behav. 100, 752-774. doi: 10.1016/j.pbb.2011.04.010
95. Robinaugh, D. J., Leblanc, N. J., Vuletich, H. A., and McNally, R. J. (2014). Network analysis of persistent complex bereavement disorder in conjugally bereaved adults. J. Abnorm. Psychol. 123, 510-522. doi: 10.1037/abn0000002
96. Rosmalen, J. G. M., Wenting, A. M. G., Roest, A. M., de Jonge, P., and Bos, E. H. (2012). Revealing causal heterogeneity using time series analysis of ambulatory assessments: application to the association between depression and physical activity after myocardial infarction. Psychosom. Med. 74, 377-386. doi: 10.1097/PSY.0b013e3182545d47
97. Roth, M. (2001). Unitary or binary nature of classification of depressive illness and its implications for the scope of manic depressive disorder. J. Affect. Disord. 64, 1-18. doi: 10.1016/S0165-0327(00)00237-8
98. Ruscio, J., Zimmerman, M., McGlinchey, J. B., Chelminski, I., and Young, D. (2007). Diagnosing major depressive disorder XI: a taxometric investigation of the structure underlying DSM-IV symptoms. J. Nerv. Ment. Dis. 195, 10-19. doi: 10.1097/01.nmd.0000252025.12014.c4
99. Sanacora, G., Treccani, G., and Popoli, M. (2012). Towards a glutamate hypothesis of depression: an emerging frontier of neuropsychopharmacology for mood disorders. Neuropharmacology 62, 63-77. doi: 10.1016/j.neuropharm.2011.07.036
100. Sass, H. (2007). Anthology of German Psychiatric Texts . Chĉne-Bourg, World Psychiatric Association. doi: 10.1002/9780470684351
101. Schmittmann, V. D., Cramer, A. O. J., Waldorp, L. J., Epskamp, S., Kievit, R. A., and Borsboom, D. (2013). Deconstructing the construct: a network perspective on psychological phenomena. New Ideas Psychol. 31, 43-53. doi: 10.1016/j.newideapsych.2011.02.007
102. Schwartz, T. L., Sachdeva, S., and Stahl, S. M. (2012). Glutamate neurocircuitry: theoretical underpinnings in schizophrenia. Front. Pharmacol. 3:195. doi: 10.3389/fphar.2012.00195
103. Shi, J., Potash, J. B., Knowles, J. A., Weissman, M. M., Coryell, W., Scheftner, W. A.,et al. (2011). Genome-wide association study of recurrent early-onset major depressive disorder. Mol. Psychiatry 16, 193-201. doi: 10.1038/mp.2009.124
104. Slade, T., and Andrews, G. (2005). Latent structure of depression in a community sample: a taxometric analysis. Psychol. Med. 35, 489-497. doi: 10.1017/S0033291704003708
105. Smeets, F., Lataster, T., Viechtbauer, W., and Delespaul, P. (2014). Evidence that environmental and genetic risks for psychotic disorder may operate by impacting on connections between core symptoms of perceptual alteration and delusional ideation. Schizophr. Bull. 1-11. doi: 10.1093/schbul/sbu122 [Epub ahead of print].
106. Solomon, A., Haaga, D. A., and Arnow, B. A. (2001). Is clinical depression distinct from subthreshold depressive symptoms? A review of the continuity issue in depression research. J. Nerv. Ment. Dis. 189, 498-506. doi: 10.1097/00005053-200108000-00002
107. Solomon, D. A., Keller, M. B., Leon, A. C., Mueller, T. I., Lavori, P. W., Shea, M. T.,et al. (2000). Multiple recurrences of major depressive disorder. Am. J. Psychiatry 157, 229-233. doi: 10.1176/appi.ajp.157.2.229
108. Szasz, T. (1974). The Myth of Mental Illness: Foundations of a Theory of Personal Conduct . New York, NY: Harper & Row.
109. Tansey, K. E., Guipponi, M., Perroud, N., Bondolfi, G., Domenici, E., Evans, D.,et al. (2012). Genetic predictors of response to serotonergic and noradrenergic antidepressants in major depressive disorder: a genome-wide analysis of individual-level data and a meta-analysis. PLoS Med. 9:e1001326. doi: 10.1371/journal.pmed.1001326
110. Tweed, D. L. (1993). Depression-related impairment: estimating concurrent and lingering effects. Psychol. Med . 23, 373-386. doi: 10.1017/S00332917000 28476
111. van Borkulo, C. D., Borsboom, D., Epskamp, S., Blanken, T. F., Boschloo, L., Schoevers, R. A.,et al. (2014). A new method for constructing networks from binary data. Sci. Rep. 4, 1-10. doi: 10.1038/srep05918
112. van de Leemput, I. A., Wichers, M. C., Cramer, A. O. J., Borsboom, D., Tuerlinckx, F., Kuppens, P.,et al. (2014). Critical slowing down as early warning for the onset and termination of depression. Proc. Natl. Acad. Sci. U.S.A. 111, 87-92. doi: 10.1073/pnas.1312114110
113. Wichers, M. C. (2013). The dynamic nature of depression: a new micro-level perspective of mental disorder that meets current challenges. Psychol. Med. 616, 1-12. doi: 10.1017/S0033291713001979
114. Wilson, R., Barker, M., and Brigandt, I. (2007). When traditional essentialism fails: biological natural kinds. Philos. Top. 35, 189-215. doi: 10.5840/philtopics2007351/29
115. Wray, N. R., Pergadia, M. L., Blackwood, D. H. R., Penninx, B. W. J. H., Gordon, S. D., Nyholt, D. R.,et al. (2012). Genome-wide association study of major depressive disorder: new results, meta-analysis, and lessons learned. Mol. Psychiatry 17, 36-48. doi: 10.1038/mp.2010.109
116. Zachar, P. (2002). The Practical Kinds Model as a Pragmatist Theory of Classification. Philos. Psychiatr. Psychol. 9, 219-227. doi: 10.1353/ppp.2003.0051
117. Zachar, P., and Bartlett, S. (2002). Basic emotions and their biological substrates: a nominalistic interpretation. Conscious. Emot. 2, 189-221. doi: 10.1075/ce.2.2.02zac
118. Zachar, P., and Kendler, K. S. (2007). Psychiatric disorders: a conceptual taxonomy. Am. J. Psychiatry 164, 557-565. doi: 10.1176/ajp.2007.164.4.557
119. Zimmerman, M., Ellison, W., Young, D., Chelminski, I., and Dalrymple, K. (2014). How many different ways do patients meet the diagnostic criteria for major depressive disorder? Compr. Psychiatry. 56, 29-34. doi: 10.1016/j.comppsych.2014.09.007
120. Zuk, O., Hechter, E., Sunyaev, S. R., and Lander, E. S. (2012). The mystery of missing heritability: genetic interactions create phantom heritability. Proc. Natl. Acad. Sci. U.S.A . 109, 1193-1198. doi: 10.1073/pnas.1119675109