Table 3.
Morphometric Studies Implicating the Amygdala in Unipolar Depression.
| Study | Sample | Age | Method | Age of Onset | Duration of Illness/# Episodes | Family History of Illness | Clinical Status at Testing | Medication Status | Comorbidity | Findings |
|---|---|---|---|---|---|---|---|---|---|---|
| (Sheline et al 1998) | 20 MDD 20 HC |
54±18 53±17 |
1.5T 1.25mm |
NR | NR | NR | Largely euthymic | 14 patients on AD | No comorbid conditions | No group differences in overall amygdala volumes but BL reduction in core nuclei volumes in MDD. |
| (Bremner et al 2000) | 16 MDD 16 HC |
43±8 45±10 |
ROI | NR | 2±3 (episodes) | NR | Remitted | AD | No PTSD. 5 patients with history of substance abuse/dependence. 1 PD. | No between group differences |
| (von Gunten et al 2000) | 14 MDD (with memory complaints) 14 HC |
57.6 58.1 |
1.5T 5mm |
NR | ±6.5 | NR | Depressed | 7 AD, 2 BZ | No neurological disorders, substance abuse | Smaller L amygdala volume in MDD. |
| (Caetano et al 2004) | 31 MDD 31 HC |
39.2±11.9 36.7±10.7 |
1.5T 1.5mm ROI |
30.5±12.5 (remitted) 26.7±11.4 (depressed) |
12.3±8.4 (remitted) 11.0±11.7 (depressed) |
NR | 21 depressed; 10 remitted. | All patients off psychotropics for 2+ weeks. | No comorbid disorders except substance abuse in remission for 6+ months. | Trend towards smaller L amygdala volume in MDD |
| (Frodl et al 2004) | 30 MDD 30 HC |
48.4±13.4 45.7±12.9 |
1.5T 1.5mm ROI |
39.3±13.4 | 9.1±10.2 | NR | Depressed | AD + lithium | No co-morbid disorders | No differences in amygdala volumes |
| (Inagaki et al 2004) | 17 MDD 51 HC |
47.1±6 48.6±5 |
1.5T 1.5mm |
NR | 1.1±1.0 (episodes) | No | Remitted | No psychotropic medication for 1+ month but 29 on tamoxifen which may have anti-manic properties (Zarate et al 2007) | No substance abuse | No amygdala volume differences in cancer survivors |
| (Lange and Irle 2004) | 17 female MDD 17 female HC |
34±10 34±6 |
1.5T 1.3mm ROI |
29±10 | 5±5 | Yes – in 7 cases but no history of BD | Depressed | No history of psychosis. No PTSD, borderline PD | AD | Enlarged amygdala in MDD |
| (Hickie et al 2006) | 45 MDD 16 HC |
52.0±12.8 55.8±10.3 |
1.5T 1.5mm |
36.1±17.2 | 15.6±16.1 6.9±9.8 episodes |
NR | Depressed | 29/45 AD | No substance abuse but comorbid axis II disorders. No head injury, neurological illness, stroke, dementia | Smaller amygdala volume in MDD |
| (Frodl et al 2007) | 60 MDD 60 HC |
44.2±11.8 41.6±12.3 |
1.5T 1mm ROI |
37.7±11.7 | 6.7±8.7 | NR | Depressed | AD | No head injury, neurological disorders, substance abuse, and personality disorders, | No group differences |
| (Macmaster et al 2007) | 32 MDD 35 HC |
14.08±2.08 14.51±2.72 |
1.5T 1.5mm ROI |
11.77±2.92 | 27.70±27.68 months | Yes | Depressed | Medication naive | No psychosis, BD, OCD, PTSD, eating disorders, substance abuse, autism, LD, medical or neurological conditions | No group differences |
| (Tang et al 2007) | 14 MDD 13 HC |
29.5±6.84 29.46±6.86 |
1.5T 1.6mm ROI |
1st episode | 5.44±5.22 months | NR | Depressed | Medication naive | No medical or neurological disorder, head injury, substance abuse. 4 with GAD | Decreased volume of R amygdala in MDD. 22; 0; −16 |
| (Keller et al 2008) | 23 MDD (with psychosis) 19 MDD (without psychosis 22 HC |
36.5±13.2 36.6±11.9 32.2±11.5 |
3T 1.5mm ROI |
27.6±11.7 27.0±14.0 |
2.9±4.4 4.0±9.3 (episodes) |
NR | Depressed | AD, MS, AP, 4 no med 8 no med, 8 AD, 3 other |
No major medical illness, seizures, head trauma, unstable cerebrovascular, endocrine conditions. No treatment with steroids, hormone replacement therapy. No substance abuse within last 6 months | Smaller BL amygdala in psychotic but not non-psychotic MDD |