Table 2.
Demographic and clinical characteristics across clusters of cases
| Variable | Cluster membership | Statistic | p‐Value | ||
|---|---|---|---|---|---|
|
Cluster 1 Simple TTM n = 63 |
Cluster 2 Depressive TTM N = 49 |
Cluster 3 Complex TTM n = 192 |
|||
| Sex | |||||
| Male | 3 | 1 | 13 | Chi‐square: 1.76 | .42 |
| Female | 60 | 48 | 179 | ||
| Mean age (in years) | 32.73 (SD 12.95) | 33.37 (SD 11.77) | 32.6 (SD 11.99) | F = 0.08 | .93 |
| Age of onset of TTM (in years) | 12.92 (SD 5.45) | 12.82 (SD 5.96) | 13.65 (SD 5.92) | F = 0.61 | .54 |
| Age of onset of comorbid MDDa (in years) | (no MDD) | 23.4 (SD 10.5) | 21.3 (SD 10.4) | F = 0.18 | .50 |
| Duration of illness (in years) | 19.81 (SD 13.25) | 20.55 (SD13.14) | 18.87 (SD 12.17) | F = 0.4 | .67 |
| MGHHPS total score | 13.38 (SD 4.28) | 14.82 (SD 5.56) | 15.27 (SD 4.65) | F = 3.75 | .02* |
| BDI total score | 3.7 (SD 3.16) | 12.8 (SD 5.81) | 12.4 (SD 8.76) | F = 5.07 | .01** |
Abbreviations: BDI, Beck Depression Inventory; MDD, major depressive disorder; MGHHPS, Massachusetts General Hospital Hair Pulling Scale; TTM, trichotillomania.
a
Of the 168 cases with lifetime MDD, only 46 (27.4%) had age of onset of MDD data available.
*
Cluster 3 cases had significantly worse hair‐pulling than those in Cluster 1 (p = .02).
**
Clusters 2 (p = .04) and 3 (p = .003) both had significantly more severe depressive symptomatology than Cluster 1 cases.